By: Jessica Moore

“Heart failure (HF) is a big problem, especially for African Americans. If you’re African American, you’re more likely than people in other ethnic groups to get HF at a younger age, and you’re more likely than others to be hospitalized. Unfortunately, African Americans are also more likely to die earlier than are other people with HF” (1). This quotation comes directly from the website of BiDil, a heart failure medication marketed specifically for African Americans, based on supposed genetic markers. This current drug, which insinuates that ‘race’ can influence someone’s health, and therefore that certain races require different healthcare treatment from others, is a recent example of the constant involvement of the concept of race in science. However, this concept seems to be losing any holding it once had. New genomic advancements have taught us that race, as a concept, and race-based treatments like BiDil, have little to no place in modern scientific thought.

The concept of race, in modern understanding, began in the Americas with the first race-based slave system in the 1600s (2). Before this, language, religion, and class were the primary determinants of a person’s position within society. It wasn’t until the founding of the American colonies that race was utilized to determine social class.

THE SCIENCE OF PHYSICAL DIFFERENCES

However, ideas of physical differences are much older. Scientific observations on the physical differences between people date back to 400 BC, with Hippocrates (3). Hippocrates advocated that environmental factors determined the differences in human populations. He stated, “The forms and dispositions of mankind correspond with the nature of the country” (4). This thought, though scientifically sound at the time, was followed by his equal belief that geographic factors not only influenced physical appearance, but behavioral characteristics as well. This represents the first notions of prejudice based on geographic stereotyping alone. This was further enhanced by the Middle Ages belief in “black sin,” that Africans were descendants of Ham, who was depicted as a sinful man, and “his progeny as degenerates” (5).

Moving into the 17th century, there was a distinct increase in the scientific study of humans, and a push for naturalists to classify humans and their differences (6). This was the result of a sweeping scientific effort at taxonomy by naturalists and their desire to categorize all living systems. Skin color, stature, and food habits were all considered in classifications, but it was ultimately decided that geographic origin was the best determinant of human differences. However, the concept of “race” was yet to be defined (6)

The concept of a “country of origin” was arguably a positive direction in classifying human differences, as it simply focused on heritage and its impacts on physical stature. However, moving into the 18th century, the development of the Americas was marked by a dramatic increase in the slave trade, leading to a degenerate approach to this classification (4). Cultural and political notions favoring the concepts of racial superiority tainted early scientific discoveries (7). This century was marked by the inclusion of behavioral and psychological observations of human differences, retroactively reflecting the “scientific” views of the Middle Ages (7). This concept led people to believe that race, and its subsequent behavioral traits, were innate and unchangeable.

With the rise of taxonomy in science, scientists began to believe that humans could be categorized into subgroups of Homo sapien (4). This is where the concept of race truly arose, along with the suggestion of a hierarchy of races, each with distinct physical, and supposedly behavioral, traits. Johann Friedrich Blumenbach is credited with defining race in 1779 with his division of humanity into five distinct racial groups: the Caucasian race, the Mongoloid race, the Malay race, the Negroid race, and the American race.8 His findings were widely based on cranial research (wherein he evaluated differences in the circumference of the head). Interestingly, he held the unpopular view of the time that races were equal and that, “there is no so-called savage nation known under the sun which has so much distinguished itself by such examples of perfectibility and original capacity for scientific culture, and thereby attached itself so closely to the most civilized nations of the earth, as the Negro” (3). However, his works would sadly be misinterpreted, and his definition of race later used to enforce the concept of innate differences among man (8).

FLAWED RACIAL JUSTIFICATIONS

In the 19th century, there was a movement to shift understanding of race from a mere taxonomic use to a biological one. This was where racial conflict became particularly rooted in scientific thought (9). Using Blumenbach’s methods, scientists Francis Galton and Alphonse Bertillon measured shapes and sizes of skulls in order to determine differences in races, ultimately relating these findings to markers of intelligence (10). This represented the conceptualization of the idea that one’s race could also reflect group differences in intelligence and character. Many scientists began to assert that these differences were obvious, and the concept of race was used to dramatically divide groups by culture and physical appearance. It is important here to remember that this ‘scientific’ belief was widely supported by the political agenda of the 19th and 20th centuries, which needed a socially acceptable justification for actions such as the Eugenics Movement and wide campaigns of oppression and genocide (11).

During the late 20th century and early 21st century, tensions rose between individuals who believed race generated a hierarchy of mankind and those who believed in human equality. Further understanding of DNA and the human genome led scientists to believe that while race, which had been socially accepted as the general classification term for differences between groups of people, was an inherited characteristic, most behavioral attributes were primarily determined by factors such as environment and culture (11). However, the social construct of race was so deeply ingrained that re-evaluating the concept of race as one with a truly sound scientific basis took much time and convincing (12). In 1978 UNESCO released a “Declaration on Race and Racial Prejudice,” which declared this important ideal: “Any theory which involves the claim that racial or ethnic groups are inherently superior or inferior, thus implying that some would be entitled to dominate and eliminate others, presumed to be inferior, or which bases value judgments on racial differentiation, has no scientific foundation and is contrary to the moral and ethical principles of humanity” (3).

Reflecting this ideal, the early 21st century has been marked by a period of increased research in how environment and culture impact behavior over race. The Human Genome Project showed that the concept of race has limited basis in genetics. Francis Collins, former head of the National Human Genome Research Institute, called race a “flawed” and “weak” concept that scientists need to move beyond.12 Racism and the concept that it has a basis in inherited characteristics produces bad science, bad healthcare, and furthermore, bad human relations (13).

As we head into the next decades of scientific development, it is important for us to look back on how race has evolved in science over time, and to recognize that it may not have a place in the sciences any longer. We must evolve past the concept of race in society, and accept what scientists have coined “geographic ancestry” instead as a definer of the physical differences present in the human population. As genetic research has come to show us, the basis for which we have justified so much prejudice and violence needs to be left in history as we take our next steps as scientists and influencers into the future. The concept of race and its prejudices, though a relatively modern construct, has no place in modern scientific society.

Jessica Moore ’21 is a freshman in Greenough Hall.

WORKS CITED

[1] Arbor Pharmaceuticals. BiDil. https://www.bidil.com/ (accessed Oct. 2, 2017).

[2] Gossett, T. Race: The History of an Idea in America; Oxford University Press: Oxford, UK, 1963.

[3] Brace, C. “Race” is a Four-Letter Word: the Genesis of the Concept; Oxford University Press: New York, 2005.

[4] Augstein, H., Ed. Race: The Origins of an Idea, 1760–1850; Thoemmes Press: Bristol, England, 1996.

[5] Snowden, F. Before color prejudice: the ancient view of blacks; Harvard University Press: Cambridge, MA, 1983.

[6] Stanton, W. The leopard’s spots: scientific attitudes toward race in America, 1815–1859; University of Chicago Press: Chicago, IL, 1960.

[7] Shipman, P. The Evolution of Racism: Human Differences and the Use and Abuse of Science; Harvard University Press: Cambridge, MA, 1994.

[8] Gould, S. The Mismeasure of Man; Norton: New York, 1996.

[9] Dain, B. A Hideous Monster of the Mind: American Race Theory in the Early Republic; Harvard University Press: Cambridge, MA, 2002.

[10] Banton, M. Racial Theories, 2nd ed; Cambridge University Press: Cambridge, UK, 1998.

[11] Hoover, D. Conspectus of History. 1981, 1.7, 82-100.

[12] Koenig, B. et al. Revisiting Race in a Genomic Age; Rutgers University Press: Piscataway, NJ, 2008.

[13] Malik, K. The Meaning of Race; New York University Press: New York, 1996.

[14] Sarich, V.; Frank, M.. Race: the Reality of Human Differences; Westview Press: Boulder, CO, 2004.

By: Jeongmin Lee

We are walking works of art. From the delicate brain to the flow of blood in our veins, the human body is a dense complex system. The surgeon is expected to cautiously open this living system to mend his or her patient before patching the patient up so that the machination of the body can resume its work. This delicate task has been handled quite differently over the ages, and currently, we are in yet another period of change due to technological advancements. Visiting previous procedures can elicit an appreciation of the surgical methods that we have in this present day.

Even in prehistoric times, people have recognized that there are situations when one must intrude a patient’s body to treat them. Archaeologists have found evidence of trephination, the practice of drilling a hole into the skull in hopes of treating mental diseases, in remains of humans dating back to 6500 BCE (1). Evidence suggests that trephination was practiced throughout the world. The people who were treated with trephination appear to have survived the procedure, as many of the skulls seem to have started healing after the perforation. A possible reason behind this procedure may be related to humoralism from ancient Western medicine.

As time passed, records describe more detailed procedures that revolve around the idea of humors. Hippocrates initiated historical medicine in ancient Greece, according to his disciples who made records under him. A common theme in his lectures was humors, four types of liquids that can affect one’s personality and well-being: blood, phlegm, yellow bile, and black bile (2). It was believed that when the humors were imbalanced, the patient was ill, so medicine was diagnosed to balance the liquids by letting out one of them. Trephination, according to Galen from the Roman Empire, had many risks. So instead, those civilizations practiced bloodletting where a hot patient with too much blood had to lose some blood to balance his or her humors. This practice remained popular throughout the Middle Ages as people believed that diseases could be washed out of the body if the blood containing the disease was drained (3). There were other surgical procedures by the sixteenth century such as amputations, which removed infected parts of the body before the infection spread. However, patients would die in pain or from further complications if the amputations were not quick enough.

Before the advent of anesthetics, amputations and other surgeries could cause the patient to die in pain, and sooner than if the patient had been left unoperated. “Time me, gentlemen” is the most recognized quote by Robert Liston, who practiced completing surgeries in record time (4). However, the quick job often left patients dying on the table or soon after. It took until 1846 before William Morton from America demonstrated how the anesthetic properties of ether can be used to complete a dental procedure painlessly.5 Anesthetics allowed surgeons to take their time when operating, greatly increasing survival rate. Anesthesia is commonly used in surgeries today.

The evolution of surgery continues as surgeons use cutting edge technology to make their incisions. To reduce exposing the body’s interiors as much as possible, some medical centers are employing technology to aid the surgeon’s accuracy and efficiency. The Robotic Surgery Center in New York has a machine that magnifies the point of interest and allows the surgeon to control a small but accurate knife to make the least invasive maneuvers.6 Overall, the history of surgery depicts stories of how procedures become overturned with new discoveries. Akin to how Liston’s quick sutures were not as important once anesthetics increased the time a surgeon could spend operating or how trephination discontinued once Western civilizations reasoned different alternatives, automated machines can find and make ideal cuts that a skilled human hand would not reliably accomplish. Currently, the machines are yet another tool a surgeon can use to minimize risks for the patient. Surgery’s history of constant innovation is what many fields strive to have.

Jeongmin Lee ’19 is a junior in Lowell House concentrating in Chemistry.

WORKS CITED

[1] Irving, J. Trephination. https://www. ancient.eu/Trephination/ (accessed Sept. 23, 2017).

[2] Osborn, D. The Four Humors. http:// http://www.greekmedicine.net/b_p/Four_ Humors.html (accessed Oct. 15, 2017).

[3] Clunie, A. Surgery…a Violent Profession. https://www.hartfordstage.org/ stagenotes/ether-dome/history-of-surgery (accessed Sept. 4, 2017).

[4] Jones, A. et al. Time me, gentlemen! The bravado and bravery of Robert Liston. https://www.facs.org/~/media/files/archives/05_liston.ashx (accessed Sept. 23, 2017).

[5] Markel, H. The painful story behind modern anesthesia. PBS [Online], http://www.pbs.org/newshour/rundown/the-painful-story-behind-modern-anesthesia/ (accessed Oct. 15, 2017).

[6] NYU Langone Health. What is Robotic Surgery? https://med.nyu.edu/robotic-surgery/physicians/what-robotic-surgery (accessed Sept. 23, 2017).

By: Michael Xie

Dr. John P. Holdren is the Teresa and John Heinz Professor of Environmental Policy at the Harvard Kennedy School of Government and Professor of Environmental Science and Policy at Harvard University. During the Obama administration, he served as the Director of the Office of Science and Technology Policy and the President’s Science Advisor, becoming the longest-serving advisor since its creation. Among numerous honors, Dr. Holdren was awarded one of the first MacArthur Prizes in 1981 and gave the acceptance speech for the Nobel Peace Prize on behalf of the Pugwash Conferences on Science and World Affairs, as the chair of the executive committee. HSR sat down with Dr. Holdren to get his take on the ever-evolving relationship between the scientific world and public policy.

MX: When and why did you first get involved in science?

JPH: I was interested in science from the time I was in grade school, and so I decided early on that I wanted to work on issues at the intersection of science and public policy—big issues such as population resources, environment development, and international security. I was interested in those issues already in high school. I went to MIT to get a technical education and majored in aeronautics and astronautics with a minor in physics. Then I did a PhD in theoretical plasma physics and worked in the fusion energy program as a physicist at the Livermore Lab, with a deal with the head of the fusion energy division that I could spend one day a week working on the wider societal implications of fusion: What was this niche in the overall energy picture? Why did we need it? What characteristics would it need to have in order to be an attractive energy resource for society in the long run? I was appointed to my first National Academy of Science committee advising the government in 1970, the same year I got my PhD. I was an early advisor in the Council of Environmental Quality. I was a member of the Energy Research Advisory board of the Department of Energy toward the end of the 1970s. I basically spent my whole life at the boundary of science and public policy but most of it with my day job as an academic.

MX: What made you decide to get involved in public policy in addition to your scientific interests?

JPH: If you really want to change the world, it’s not enough to understand the world better. Science is about increasing our understanding of ourselves and our world and our universe and how it all works, but if you want to fix what’s wrong in terms of afflictions of the human condition—poverty, disease, conflict, and inequity—then you have to be prepared to apply those insights about how the world works and how technology works, and you have to get into the policy debate. You have to be prepared to engage with the different sectors of society rather than staying in your academic Ivory Tower. You need to engage with business, with government, and with civil society to get things done, and I was always interested in getting things done.

MX: What do you see as the major differences or disparities in government work and university work?

JPH: The wonderful thing about an academic setting is you have a tremendous amount of freedom, not only to choose what you work on but to spend whatever fraction of your time you want on a relatively small number of issues, whereas in government you don’t have a lot of choice. If you’re in the position that I was in, which was the Science and Technology Advisor to the President of the United States and the Director of the White House Office of Science and Technology Policy, you have to be engaged in everything that relates to policy issues the President is focused on—that means the relation of science and technology with the economy; with biotechnology and public health; with energy, environment, climate change; with national and homeland security; with environmental conservation and protecting the oceans—and so you don’t have the luxury of spending as much time as you might like on one or two or three things.

You also have to deal, much more than in academic life, with emergencies. Emergencies like the H1N1 flu that materialized early in the first term or even before that with the economic recession, which the Obama administration inherited and needed very quickly to figure out how science and technology could be applied to economic recovery. Then, the Macondo oil spill, the Fukushima nuclear accident, the Ebola outbreak. These emergencies come along when you’re in government, and they always tax your ability to do everything else you were supposed to be doing and deal with the emergency at the same time. Another big difference is, in academic life, you have the fun of having students, teaching classes, advising masters and doctoral dissertations, and working with postdocs. The closest thing to that in government is when you have fellows and interns in offices. You have some interaction with younger people who are in the process of learning new things and applying them to try to influence things for the better, but there’s a lot less of that because your other duties take up so much time. One of the principal functions of the university is teaching and mentoring, whereas that’s a very secondary function in government.

MX: How have you seen science and policy traditionally interact and how has that evolved over the years?

JPH: The interaction of science and policy goes back a very long way—certainly, to the administration of Abraham Lincoln when the National Academy of Sciences was founded. The two-way street between science and technology for policy—that is, how can insights from science and technology assist in the policy process, and, the other side of that coin, how can government choices and investments advance the state of science and technology in society— goes back 150 years.

It underwent a major transformation during WWII when Franklin D. Roosevelt appointed distinguished MIT engineer and technical entrepreneur Vannevar Bush as director of the new Office of Scientific Research and Development in the White House. Bush became the first full time science and technology advisor to a US President. Most of that advice was on matters related to the war, and because science and technology for the military had a transformative effect during the war, Bush had the idea that similarly applying science and technology to civilian needs could have a transformative effect on the whole society. He wrote a book at the end of WWII called Science the Endless Frontier. It led ultimately to the creation of the National Science Foundation in 1950. There really emerged a symbiosis of government academia and industry, which was responsible for a large part of economic progress made by the United States over the ensuing decades. The symbiosis involved government paying for fundamental and early stage applied research in the universities and national laboratories, then the private sector picking up the most promising ideas that had emerged from that effort and converting those ideas into practice. Eric Lander, who was my co-chair of the President’s Council of Advisors on Science and Technology and Eric Schmidt, who was the executive chairman of Google, wrote an op-ed piece called the “Miracle Machine” about how this symbiosis worked and arguing that it was very important that we not dismantle the “Miracle Machine” by reducing the government’s investments in research and development.

Initially after the war, most of the science and technology advice Presidents needed from their advisors related to issues such as nuclear weapons, early warning systems, bombers, and missiles, but over time as the effects of this “Miracle Machine” became more apparent, the advice that Presidents wanted expanded. In the Clinton administration the OSTP had a maximum of 66 people. That was bigger than in the previous administration, which was bigger than in the administration before that. The reason it kept growing is that domains in which Presidents needed to be paying attention in science and technology kept getting broader.

In the Obama administration, we ultimately had 135 people in the OSTP. I think the Obama administration was probably, of all modern presidencies, the administration most engaged with science and technology issues. President Obama understood how and why science and technology mattered, and so he was very interested in how we could use science and technology to advance society’s interest. We in the Obama administration launched a very wide variety of initiatives in biomedicine and public health, a whole set of initiatives on science and technology for the economy, initiatives on open data, and a whole set of initiatives on energy and climate change.

President Obama was seized with the proposition that our challenges and opportunities were so big and our resources so limited that partnership was essential, and virtually every one of the initiatives was constructed as a partnership with engagement of the government with the private sector, universities, and civil society. The other thing, which has grown over the years, has been international collaboration in science and technology. Some of the earliest collaborations internationally were on fusion energy in the late 1950s. The areas of collaboration expanded subsequently to include space, and the International Space Station today is a terrific example. One of the instructions that President Obama gave me at the beginning of the administration is to build up further our science and technology collaborations with China, Russia, India, Japan, the European Union, Brazil, Korea, and we did that. This dimension of science technology and policy being an issue that is international has become very pervasive.

MX: How has the changing political climate and transition to the Trump administration affected the scientific world? How much does governmental change affect scientific thought?

JPH: The choice of who is going to be the President potentially has quite a lot of impact on what the role of science and technology in government is going to be and what the role of government in supporting science and technology is going to be. So far, President Trump has appointed a number of people to positions of great responsibility who don’t appear to be interested in scientific or technological facts. You’ve got people who deny the reality of climate change running the EPA and the Office of Management and Budget in the White House, and people who are at least skeptical about the reality of climate change running the Department of Interior and the Department of Energy. This is absolutely extraordinary in terms of a lack of interest in the relevance of science to the government decision-making. A lot of the science and technology appointments are still vacant many many months into the administration. You have to assume either the administration has been incredibly distracted by other things or that they’re just not very interested in the role of science and technology in these departments and agencies. I have no successor. There is no one that has been nominated to be the Director of the OSTP, no one who is serving as the Assistant to the President for Science and Technology.

In addition, the Trump administration has proposed budgets that would severely cut government investments in research and development. One has to hope that the Congress, which ultimately appropriates the money, will not accept the Trump administration’s proposals. Trump’s proposals would cut research on energy technology by about 50 percent. This is after we committed in Paris with 19 other countries— now 21 other countries have joined—to double the government’s investments in clean energy research and development in five years, and now President Trump proposes to cut it in half in one year. President Trump proposed to cut the National Institutes of Health by 20 percent. The Congress does not seem inclined to do it, fortunately, but cuts at the National Science Foundation and cuts at the National Oceanic and Atmospheric Administration indicate a lack of understanding about the role of government investments in science.

President Trump and others around him have said, “If research is worth doing, the private sector will do it.” This is not actually realistic. The private sector will never invest in very basic research to the extent that societies need and require because the uncertainty is too great, the risks of failure too high for the private sector to do it. That’s why we’ve had and needed this symbiosis between government making investments in basic research, taking those risks on behalf of all of society because what we know from history is that you can’t predict which basic research project is going to yield big gains. We know when you look at the whole portfolio that some of them are transformative. Think about the laser, which emerged from absolutely fundamental research. The people who figured out the laser had no idea that 50 years later that lasers would be the way we do eye surgery, the way we cut metal, the way we copy documents, the way we play videos. No private enterprise would have invested in all the research needed to do that. Even more recently: the fracking revolution and all the natural gas that has enabled us to displace a lot of coal and electricity with much cleaner natural gas. The discoveries that enabled that were all funded by the federal government. They weren’t funded by the energy companies. There’s a lot of reason to worry about what the current administration is doing. Now, we will have to some extent, the private sector, states, cities, civil society organizations, picking up some of the things that the government drops, but the government’s role is too important and too costly for all of this to be picked up.

MX: Do you think we have enough scientists involved with policy at the current time?

JPH: I have said for a long time that it would be a good thing if more scientists devoted some of their time to thinking about the implications of their science, the implications of technology for society—if they spent some of their time explaining to a wider audience what they do, why they do it, how they know what they know, what the implications are for society. In 2007, when I was the president of the AAAS, I said that I thought scientists and engineers should tithe 10 percent of their time, no matter what their main focus was, to thinking, talking, and writing about the wider implications of what they do because we have a society now where virtually every issue is infused with science and technology. We need our scientists and technologists to do a better job communicating with everybody else about what those connections are. So, the short answer is, we don’t yet have enough scientists and technologists engaged with public policy. We have a lot— literally thousands—of scientists participate in the studies of the National Academies of Science and Engineering and Medicine, advising the government on different topics. The numbers aren’t small but it’s not as big as we need it to be. Additionally, we need to get better at STEM education, so that we have not just assurance that the next generation of Nobel Prize winners will be educated and trained but that we will have the tech-savvy workforce the jobs the twenty-first century increasingly require and the science-savvy citizenry that democracy requires if it’s going to work in an era where science and technology are infusing virtually every public policy issue.

MX: What areas of science will be the most important for policy and what areas of policy will be the most important for science in the next few years?

JPH: Many people say that the end of the 20th century was the start of the age of information technology and the 21st century is going to be the age of biotechnology. I think increasingly it’s all of the above. I think we’re seeing more and more interactions between biotechnology, information technology, nanotechnology, robotics, and other fields. We need to have ways to regulate these very rapidly moving technologies that protect public safety but at the same time not stifle innovation. That’s an enormous challenge for policy. A whole array of defense technology is going to continue to be important: autonomous vehicles, robots of various kinds. Information warfare and cyber security has obviously become very important. We have to figure out what we’re going to do to protect privacy in an era when all kinds of information can be put together to learn things about people’s “private business.”

There’s also a great challenge around employment. If we have self-driving cars and trucks, a lot of people are going to become unemployed. What are those people going to do? In the past, we’ve largely succeeded in inventing new jobs just about as fast as old kinds of jobs were made obsolete, and so we don’t have a huge unemployment rate in this country. But the unemployment rate is too high in too many places, and we need to worry about technological unemployment, where technologies replace jobs faster than jobs are created. Artificial intelligence is also becoming more important. There’s lots of specialized artificial intelligence out there already. There are people thinking it will become possible, over the next several decades, to have a more generalized artificial intelligence. How is that going to be used? How are we going to benefit from its upside while protecting ourselves from its downside? These are going to be huge policy issues.

Michael Xie ’20 is a sophomore in Leverett House concentrating in Chemistry and Physics.

WORKS CITED

[1] J. P. Holdren, personal interview, Oct. 16, 2017.

By: Priya Amin

What is the distal limb pattern of tetrapod forelimbs? The tetrapod distal limb pattern consists of three segments: the stylopod (the first segment of the limb including the humerus), the zeugopod (the second segment of the limb including the radius and ulna), and the autopod (the hand) (1).

What is the basic phylogenetic breakdown of the fin to limb evolution? The vertebrate group Osteichthyes diverges into Sarcopterygii (lobe-finned fish) and Actinopterygii (ray-finned fish) according to several physical characteristics. Most importantly, Sarcopterygii develop lobe fins, which include a central axis and radial fin rays. Within Sarcopterygii, a group named tetrapodomorpha develop a partial distal limb pattern which lacks digits but includes a humerus, radius, and ulna. Early tetrapods like Acanthostega and other amphibians develop digits, and the full distal limb pattern seen in humans is born! Diverging groups of derived tetrapods specialize and adapt this ancestral pattern of a stylopod, zeugopod, and autopod, which define the distal limb pattern.

COELACANTH (Middle Devonian—Present)

This sarcopterygian (“lobe-finned” fish) showcases the ancestral fin model for tetrapods. Accordingly, the lobed fin of coelacanths has a central axis with fin radials. Because radials deviate on both sides of the axis, the fin is considered to be biserial (2).

In addition, because the species Latimeria is considered a ‘living fossil,’ we can study the movement and morphology of the musculature of this lobe-finned fish (3). Accordingly, a study by Miyake et al. revealed that the musculature in the ‘shoulder’ and ‘elbow’ joints of living coelacanths shows an ancestral condition of movement with the human stylopod (humerus) (4). In particular, the stylopods of Latimeria and Homo sapiens both have paired musculature that is necessary for maintaining stable posture and achieving weight-bearing positions. The presence of this musculature in Latimeria suggests that the basic muscle arrangement needed for terrestrial life may have existed at the earlier stages of tetrapod evolution.

EUSTHENOPTERON (Late Devonian)

Eusthenopteron, a tetrapodamorph, features some of the earliest evidence of a distinct humerus, ulna and radius, which evolved from the ancestral sarcopterygian lobe-fin. Research has shown that its humerus has growth patterns similar to those of tetrapods (5). However, its tetrapod-like humeral characteristics are not terrestrial adaptations. A study by Meunier and Laurin revealed that the long bones of Eusthenopteron are very similar to tetrapod long bones (6). Furthermore, the long bones of Eusthenopteron seem to have been capable of supporting more mechanical stress than the fins of extant acintinistians like Latimeria, which has implications for enhanced movement.

PANDERICHTHYS (Late Middle Devonian)

The flat, L-shaped humerus of Panderichthys represents a key early adaptation for tetrapod evolution: the limb would now be able to prop a large head and support limited front-to-rear movement needed for walking (7,8). The blade-like radius and ridge-and-groove surface of the ulna of both Panderichthys and Tiktaalik represent another ancestral condition of the tetrapod forelimb. In addition, in a study by Boisvert et al., a CT scan revealed previously undiscovered distal radials (9). Before this discovery, the prevailing notion was that tetrapod digits were newly evolved structures. Consequently, the distal radials of Panderichthys (as well as the distal radials of Tiktaalik) have been identified as the possible ancestral condition for digits and human fingers.

TIKTAALIK (Late Devonian)

The pectoral fin of Tiktaalik represents the key functional and morphological transition state between fins and limbs. Like other tetrapodomorphs, Tiktaalik has retained dermal fin rods. Like early tetrapods, its partial distal limb morphology includes a humerus, radius, and ulna; however, it lacks digits. The fin is relatively narrower and stouter than the fins of other tetrapodamorphs. In addition, the fin of Tiktaalik differs significantly from other tetrapodomorphs due to its expanded endoskeleton and reduced dermal exoskeleton. This limb morphology suggests a specialized adaptation for locomotion in shallow floodplains, including the capability for flexion and extension (10).

ACANTHOSTEGA (Late Devonian)

Possessing eight digits, Acanthostega was a primarily aquatic, early tetrapod with limited limb movement (1). Its relatively flat articular surfaces suggest limited flexibility at the wrist and elbow; as a result, the limb most likely acted more as a swim paddle than a more derived tetrapod limb. With the presence of digits, the digital arch of Acanthostega is noticeably more curved (2). Furthermore, in comparison to primitive tetrapod fins, the limb of Acanthostega is distinctly broad and flattened (7). Acanthostega demonstrates the full distal limb pattern ancestral to all derived tetrapods, including a stylopod, zeugopod, and autopod.

HOMO SAPIENS (Present)

Much further derived than Acanthostega, we have evolved a very specialized form of the distal limb pattern. The stylopod includes the humerus, the zeugopod includes an elongated radius and ulna, and the autopod consists of carpals, metacarpals, and phalanges (11). Capable of full flexion and extension, the human limb has fully adapted for movement on land.

From lobe-finned fish to humans, the evolution of the distal limb pattern can be traced along the phylogenetic tree. This pattern defines the three segments of the tetrapod forelimb. By studying this transition, we can see how our arms and legs have evolved for movement on land. And, we can appreciate our fish ancestors!

Priya Amin ’19 is a junior in Pforzheimer House concentrating in Integrative Biology.

WORKS CITED

[1] Laurin, M. How Vertebrates Left the Water; University of California Press: Berkeley, CA, 2010.

[2] Mednikov, D. N. Paleontol. J. 2014, 48(10), 1092-1103.

[3] Cloutier, R.; Forey, P. L. Environ. Biol. Fish. 1991, 32(1-4), 59-74.

[4] Miyake, T. et al. Anat. Rec. 2016, 299(9), 1203-1223.

[5] Sanchez, S. et al. Proc. R. Soc. Lond. Biol. 2014, 281(1782), 20140299.

[6] Meunier, F. J.; Laurin, M. Acta Zool. 2010, 93(1), 88-97.

[7] Shubin, N. H. Science. 2004, 304(5667), 90-93.

[8] Clack, J. Science. 2004, 304(5667): 57-58.

[9] Boisvert, C. A. et al. Nature. 2008, 456(7222), 636-638.

[10] Shubin N. H. et al. Nature. 2006, 440, 764-771.

[11] Mariani, F. V.; Martin, G. R. Nature. 2003, 423(6937), 319-25.

By: Will Bryk

Without realizing it, you and everyone you know have been desensitized to the biggest questions of existence.

Every human gradually accumulates consciousness and awareness of his or her existence from the time of birth up through the teenage years. A baby simply does not have the means to contemplate its own existence, while a child does a bit more, and a teenager does. To see why this decade-long process desensitizes us, imagine instead that evolution had gone another way. Imagine that, somehow, only once our bodies and brain were fully grown and ready would we “turn on” and open our senses to the world. Being born would feel like popping into the universe with a fully capable brain and body, but without any knowledge of the universe.

Suppose you were just born this way. A second ago, you emerged from non-existence to full existence instantly. What would your first thoughts be? You would probably not casually start living as you do now. You would probably look around frantically, limbs flailing in all directions, blood pumping, brain racing, knees weakening, collapsing to the floor, and screaming out of sheer bewilderment, “WHAT IS THIS? WHERE DID THIS COME FROM?” The urge to know those answers would be so strong that it would fully encapsulate your being for many years. This “awakening” to the mystery of existence would be the most significant moment of your life, and the sheer memory of it would stir the most powerful of emotions. It is plausible that many people in such a hypothetical world would frame their entire life mission around answering these fundamental questions about existence.

We do not live in this hypothetical world. In our world, we are desensitized to the mystery of existence. Despite how essential, how fundamental, how relevant these questions are to our short existence in this place, most people do not think about these questions. You do not often see people walking around in the street with their arms out in shock, wondering what anything is or where everything came from. But sometimes late at night, with the right music playing and not much else distracting your mind, these questions about existence reappear. They become as obvious as daylight, as important as anything in your life could possibly be. In such moments, we yearn for answers.

Many in today’s age look to science as a beacon of hope to figure out the answers to these deep questions. After so much recent scientific progress, it is natural to expect the trend to continue until even such questions are answered. However, these fundamental questions about existence are precisely the questions that science cannot answer. This great mystery is precisely the one that science can never uncover. It is not just that science has not found answers to these questions yet; it is that science will never find answers to these questions. What follows is an argument in support of the position that science is fundamentally limited in that it cannot answer the deepest, and in some sense, most important questions.

HOW FAR WE’VE COME

There is no dispute that the scientific enterprise has become a beaming torch lighting the path forward toward our understanding of the cosmos and our place in it. The past 500 years of scientific progress is a testament to the power of this enterprise. Consider the world in 1500 AD. The universe consisted of the Earth, moon, sun, and the stars, which were visible to the naked eye. Stars were just a name for strange dots in the night sky. The origin of these celestial objects was either some mystical force or some complete unknown, depending on whom you asked. We also had no clue where people came from, or where any living beings came from for that matter. There was no knowledge of a microscopic realm. People fell ill and died without explanation. The fastest mode of communication was horseback or boat.

Compare this to the world of 2017. We now know we live in a universe with hundreds of billions of galaxies, each with hundreds of billions of stars, many of which have their own planets. Stars are gigantic balls of nuclear fusion. We understand how the planets and stars formed from disks of dust. Evolution tells us the wonderfully detailed story of where humans and all living organisms come from. We have discovered a breathtaking microscopic world no less detailed than our own. We’ve even discovered underlying physical laws that explain the motion of matter. With all this new understanding, we have invented technologies that probe unseen worlds from the molecules of life bouncing around in your finger to the planets of stars thousands of light years away. We now understand the causes of most illness. We can communicate by video with anyone on the globe. The totality of human knowledge is at one’s fingertips at any second. We routinely fly in giant birdlike machines we call airplanes. There are human footprints on the moon.

The mark of science on the advancement of mankind is undeniable. If a visitor were brought to 2017 from the 1500s, they might attribute this unbelievable advancement to some sort of sorcery, but it is instead due, in large part, to a very meticulous method of learning about the world—the scientific method. The scientific method has been instrumental in forming our understanding of nature. It acts like a truth sieve allowing false theories to pass through, leaving only the truth behind. Equipped merely with hypotheses, and physical experiments that test the hypotheses, practitioners of the scientific method were able to uncover general laws that the universe follows. That such a simple method can be so successful is somewhat astounding. Nevertheless, humans are interested in more than just finding the laws of nature. Many will not be satisfied until we know not only the laws, but also the explanations behind the laws.

TURTLES ALL THE WAY DOWN

Unfortunately, though the scientific method might be a fantastic tool for discovering fundamental laws of nature, it is simply incapable of providing the explanations for these fundamental laws. For instance, Newton pieced together many observations and hypothesized the law of gravity (Fg = Gm1 m2 /r2 ) in the late 1600s. The theory matched observed orbital data and revolutionized our understanding of the universe. Yet Newton also wrote, “Hitherto we have explained the phenomena of the heavens and of our sea by the power of gravity, but have not yet assigned the cause of this power.”1 Newton admitted that the gravitational cause, or explanation, for the motion of the heavens lacks its own explanation. Einstein in fact came along and discovered an explanation. He found that Newton’s law of gravity was an approximation of a deeper truth, namely that gravity was due to curvatures in space-time. However, we now find ourselves in the same problem. If you ask the natural question why space-time has such properties, then you are back in Newton’s shoes a little bit wiser but no more satisfied. The fundamental law changed from Newton’s equation to Einstein’s, but the explanation for the fundamental law still escapes us. Newton’s quote could very well have been attributed to Einstein.

Take another example of unsatisfied explanation. The electromagnetic force is a fundamental force of nature described by Coulomb’s law. The strength of this force is dependent on a certain constant that we call Coulomb’s constant, or k for short. We have a large body of observations that indicate that the value of k is roughly 9 × 109 Nm^2 C^-2. Because of that value, the sun continues to shine, buildings do not collapse, and you can get up in the morning. But why does k equal that particular value? Is it possible that k could have instead equaled 8 × 10^9 , for example? If it is not impossible to imagine a universe in which k equaled 8 × 10^9 , then there must be an explanation for why our universe is governed specifically by k = 9 × 10^9 . Yet the scientific method provides no explanation for this particular value. Thinking in this way, there are all sorts of constants and laws whose fundamental explanations science does not currently provide. Why these constant values, and not others? Why this physical law, and not another? These are the more fundamental questions, the ones we must answer in order to really understand the universe, and yet they are precisely the ones for which science does not have answers.

A physicist might respond that there could be a physics-based explanation for fundamental laws, or for the strengths of constants, but that we have not discovered it yet. It may very well be true that in 100 years, the next Einstein is able to explain the value of Coulomb’s constant. The problem is that this physics-based explanation would itself rely on some assumed axiom, whose explanation would be unknown. At any point in the history or future of science, there will be a set of fundamental laws whose explanations are unknown. Any time an explanation for a fundamental law is discovered, that explanation will itself rely on deeper fundamental laws whose explanations are unknown. Maybe a physicist would instead respond that there are an infinite number of universes, and that we just happen to live in the universe where the laws are the way they are and the constants are the values that they are. Again, we now could ask what is the explanation for the infinite number of universes and why does each one have its particular properties. No matter the explanation, there will always necessarily be a deeper explanation that escapes our grasp.

This central limitation of science is humorously represented by the archetypal curious child. The child asks “Why is the sky blue?” The father, who in this example happens to be a scientist, responds, “Because molecules in the air scatter blue light more than red.” “But why?” “Because of quantum mechanical phenomena.” “Why?” “Because that is how the world works on the quantum level” “Why?” “Because that’s just how things are.” “Why?” Exhausted, the father pauses, considers the big questions for a few seconds, and then responds, “Because I said so!” The moral of the story is that we can always seek a deeper explanation. The child recognizes this. We adults come to recognize this too when annoyed by the child. We then realize that our foundational explanations of the world are mere assumptions based on observation, not pillars of self-explaining truth.

DISSATISFACTION GUARANTEED

A scientist might now note that if we keep making progress and keep finding deeper and deeper explanations, then we are making progress toward a more fu

ndamental understanding, even though, by the arguments above, we cannot reach fully satisfactory answers. We may come up with a singular theory that explains the physical laws and the strength of physical constants—say the conservation of some quantity X, for example. Of course one can ask for the explanation why the conservation of X must hold. But at least we have reduced two questions to a singular, more fundamental one. Science has done this for 500 years. At first we had unlimited numbers of questions about how everything worked. Now we have an understanding of physics that reduces physical phenomena to a small set of laws that can be written on a T-shirt. We might not yet know the full nature of these laws, but in a very real sense, we have come to deeper understanding. So maybe it is true that while science cannot find the explanations for the most fundamental laws, we can be satisfied in our advancement toward those explanations.

This viewpoint is satisfying for many questions. A computer scientist does not need to know how computer chips work in order to code up a website. Similarly, when a father wants to know why the sky is blue, he does not keep asking “Why?” until he arrives at the fundamental laws of the universe. The father is satisfied at some explanatory depth, maybe that atoms scatter blue light more than red, and does not keep asking “Why?” Both the computer scientist and the father recognize their ignorance of the deeper explanations, but at some point, they do not continue to ask for practical reasons. They are satisfied not knowing the deepest explanation.

But there are certain questions that require an explanation which itself needs no further explanation in order to be satisfied. Questions like, “WHAT IS THIS? WHERE DID THIS COME FROM?” are examples of such questions. Unlike the father or the computer scientist, an explanation that X answered these questions would only be satisfying if X needed no further explanation. Right after popping into existence in the “awakening” scenario described earlier, if someone told you that there was a being that created everything, you would not be satisfied. Even though the two questions were reduced to one—“Where did the being come from?”—you would feel unsatisfied until you knew the explanation behind this being, and the explanation behind that explanation, and so on. You would only be satisfied once you somehow had a self-explained explanation, an explanation that needed no further explanation.

Because science is an observational discipline, it always relies on some assumptions whose explanations are unknown. But we cannot have deeper unknowns if we want satisfying answers to the most essential questions. Science therefore cannot answer the most essential questions. At some depth, the torch burns out.

LIGHT AT THE END OF THE TUNNEL

So far, we have concluded that some questions are unanswerable by science. All this argument implies is that our prized scientific method of arriving at truth is limited. It does not imply that the truth itself is limited. The scientific method cannot answer the deepest of questions, but that does not imply that the answers themselves do not exist. The torch burns out at some depth, but there very well could be more to explore down the tunnel. In fact, there are strong arguments in favor of the position that there must exist answers to these questions. One of the best arguments is simply that the alternative is too absurd to be taken seriously. Though it is certainly possible that answers to recursive questions, such as where the universe comes from, do not exist, it just seems too absurd. It hurts the brain to think that the universe could exist without having an explanation for existing, because we can imagine it being another way and it is not, which warrants an explanation. But this argument is not a proof. It could be a quirk in our brains that we require explanations for all things. One way, still, to get around the potential quirk is to say that even if there is no explanation for the universe’s existence, then that in itself is the deepest answer. In other words, if it is true that there is no fundamental explanation, then that truth becomes the deepest answer, and if you understood that truth you would understand how it could be that there is no fundamental explanation.

We have now come to the conclusion that the scientific method cannot find the answers to the deepest questions, and yet we think these answers must exist. In that case, what do we do if we want to reach those answers? Unfortunately, it may not be possible for human brains to discover these answers. Just because the answers exist does not mean that humans can reach them. For example, we know a fish will never understand general relativity no matter how many millions of years we try to teach it, so we might be like the fish and general relativity like the deepest answers.

Actually, if you think about it, the previous statement was incorrect. There is in fact hope for the fish—because the fish can evolve! The fish and its whole species may not currently be able to understand general relativity, but we know that after a few hundred million years, fish evolved into humans who were indeed able to understand general relativity just 100 years ago. Humans are like the fish. Though the human species doesn’t even have the correct tools to search for the deepest answers, like a fish lacking the tools to understand general relativity, we do currently have the ability to change ourselves until we have the correct tools, like a fish realizing that it could evolve until it has the correct tools.

It seems likely that we would need to enhance our brains in order to comprehend a self-explaining explanation, because such a concept is currently incomprehensible. Artificial intelligence is one example of a technology that presents a realistic opportunity for rapid brain enhancement. For example, we may in the near future be able to mentally connect to a machine with astronomical intelligence at a level we currently cannot grasp. Maybe once we can achieve a certain level of extreme intelligence we would then have the tools to find the deepest answers. If we cannot prove absolutely that this scenario is impossible, then, by definition, it is possible that this artificial intelligence opportunity, or some other brain enhancement opportunity, may arrive within our lifetimes.

It is therefore unlikely but possible that we will discover the answers to the deepest questions within our lifetimes. This is not a conclusion to take lightly. In our lifetimes, it’s possible that we can learn the answer to the totality of existence. From the perspective of someone who went through the “awakening” scenario, it is obvious that there is no greater goal. Maybe it should be obvious to us as well.

William Bryk ’19 is a junior in Quincy House concentrating in Physics and Computer Science.

WORKS CITED

[1] Newton, I.; Frost, P. Principia; Macmillan and Co.: Cambridge and London, 1863.

By: Kelvin Li

INTRODUCTION

Sight, if not the most brainpower hungry sense, is certainly the one we use the most. Think about it, our lives are inundated with visual stimulation from intellectual processes like reading text, watching videos, and interpreting body language and facial expressions to more simple tasks such as walking in a straight line and anything that requires hand-eye coordination. Simply put, being alive depends a great deal upon the power of eyesight.

And yet it’s startling to think about all the things that are invisible to human eyes, the tiny invisible things that power the whole world. After all, eyes are only cameras (albeit extremely versatile ones), and like all cameras, they have a limit to how much they can zoom in. The desire to view the things beyond the ability of the eye has long captivated humans. Only in relatively recent history (compared with the entirety of human existence) have they succeeded in beating the eye in viewing power. An entire field of science has been created to delve into the depths of the physical world; its name is microscopy and here is its history.

SIMPLE AND COMPOUND LIGHT MICROSCOPY

As early as the thirteenth century, there is record of lenses in the form of water-filled glass spheres being used as magnifying glasses by jewelers to cut gems. Even before that, Euclid in the third century BCE had elucidated the mechanics of image formation with mirrors and Ptolemy in the second century CE had posited a description of refraction (1,2). Interest in lenses initially stemmed from the desire to correct vision dysfunctions and indeed, accurate corrections for nearsightedness and farsightedness with concave and convex lenses respectively were described by mid-sixteenth century Italian scientists (2).

At its simplest, a microscope is just an extremely strong magnifying glass. The technical distinction between vision correction lenses and a microscope is just the degree of magnification. Our eyes can at best see differences of about 0.1 mm. Anything that has a resolving power stronger than that, anything that can clearly show images finer than 0.1 mm, is thus considered a microscope (3). It’s rather difficult to pin down who created the first lenses that had this sort of magnifying power because the 0.1 mm threshold was not a specification that opticians recorded. However, we do know that by the mid-seventeenth century, Antonie van Leeuwenhoek, an amateur Dutch biologist, had essentially perfected the art of crafting single lens microscopes.

Van Leeuwenhoek was not particularly skilled at using the microscope, rather it was his expert craftmanship of the instrument itself that secured his place in the history of microscopy. Leeuwenhoek’s ability to grind lenses to minute focal lengths and mount them securely in the instrument resulted in the best single lens (as opposed to compound or even non optical) microscopy work.1 His best microscope could resolve close to one micron (10-6 meters) or a magnification of about 300 times. He is credited with discovering sperm cells and blood cells, producing the first detailed drawings of rotifera and infusoria, and obtaining the first images of bacteria (1,3). The clarity of van Leeuwenhoek’s simple microscope images would not be surpassed until over a century later, a testament to the quality of his microscopes.

Simple microscopes, though, are not the microscopes that most people first encounter in their high school biology classes. Those would be compound microscopes, and allegedly the first was invented by the father and son team of Hans and Zacharias Jansen near the end of the sixteenth century (3).

Compound microscopes, from a mechanical standpoint, are equivalent to an inverted telescope. They consist of two lenses with the second magnifying the image produced by the first lens both affixed to a tube that can move relative to the specimen (4). The system of lenses used in compound microscopes affords them tremendous range in magnification and some of the earliest work was done by Robert Hooke, an English scientist who produced stunning images of small animals and plant cells that showed off the power of the microscope.

ABERRATIONS

Despite the quality of Hooke’s drawings, compound microscopes lagged behind simple microscopes in image clarity. This was due to optical aberrations that emerge when light is passed through multiple lenses, namely, chromatic and spherical aberrations. As the name chromatic aberration implies, compound microscopes had trouble with accurately transmitting color. As Newton showed with his famous experiment with the prism, white light is comprised of all the different colors of light, each having a different wavelength. This difference in wavelength is what causes problems for a compound microscope. Light is bent different amounts depending on its wavelength with shorter wavelengths refracting the greatest and this results in each color focusing at a different point. Obviously, this is not ideal since the retina is fixed and cannot separate to accommodate different focal points. What results is an image that is ringed in colored halos (3).

The solution to this distortion came from two people, Chester Hall and John Dolland. Hall discovered that different types of glass dispersed colors different amounts (3). Dolland took that discovery and by experimenting, found that by combining two glass types and lens powers, he could bring the outlying colors of red and blue into focus and reducing the blur by a factor of ten (2). This set up is called an achromatic doublet—achromatic because it reduces chromatic aberrations and doublet because the lens is comprised of two pieces of glass. Though they were at first used only in telescopes because the large sized lenses were easier to craft, microscopes eventually caught up in the nineteenth century and the images produced were no longer color distorted.

The second major kind of distortion associated with compound microscopes was spherical aberration, which arose from the curved nature of small lenses. Light that strikes the edges of the lens is refracted significantly more than light striking near the center of the lens, resulting in a difference of focal length and a blurry image (5). Before the nineteenth century, there were two imperfect solutions to spherical aberrations. One approach was to use a lens with less curvature and consequently a smaller difference in refracting power between the edges and the center of the lens; however, this resulted in a lower magnifying power (3). The second approach was to limit the amount of light that could strike the lens to a narrow angle around the center, but this limited the resolution of the microscope.3 Both of these approaches did not allow for greater enlargement power. It wasn’t until the 1830s that the work of Joseph Lister managed to fix the problem.

Lister demonstrated that by lining up a series of lenses each with a small degree of magnification, only the first lens contributed to the spherical aberration (3). This resulted in high levels of magnification with minimal aberrations. Though the hassle of positioning and fixing the lenses limited its ease of use, compound microscopy’s stronger resolving power eventually won over scientists. To this day, compound microscopy is used commonly in all sorts of settings from high school biology classes to laboratory settings and is powerful enough to view bacteria in clarity.

SHIFT AWAY FROM OPTICAL MICROSCOPY

Optical microscopy is wonderfully convenient when viewing objects at the wavelength of visible light (approximately 400-700 nanometers), but with advances in theory in the early twentieth century, there was a need for better resolution in microscopy. Around this time, the French physicist Louis de Broglie theorized that electron beams could behave like waves and calculated that they would have a wavelength of about 5 picometers, or about 100,000 times smaller than visible light (6). This prediction paved the way for a new era of microscopy. Electron microscopes operated by shooting a beam of electrons rather than photons at a specimen and quickly surpassed optical microscopy in magnification.

Before diving into the advances in electron microscopes, it makes sense to reason out why electron microscopy returns such stunning results. It turns out the reason is that shorter wavelengths increase microscope resolution. Long waves have large spaces between successive peaks, and thus will pass over small specimens returning no signature and thus no image. Short waves, on the other hand, have peaks spaced much closer together and thus will hit the target and leave a detectable shadow or bounce back signature much in the same way that light leaves shadows when it hits an object. Though humans can’t see electrons like they can see photons, a fluorescent plate placed near the specimen is able to translate the invisible electrons into a visible image.

Electron microscopes, as one can imagine, are much more advanced than light microscopes. For starters, electrons cannot travel far in the atmosphere so electron microscopy must take place inside a vacuum (6). This increased difficulty in set up is balanced, however, by the fact that magnification is controlled not by accurately positioning the lenses and specimen, but by focusing the beam of electron to different degrees.6 Additionally, the microscope must also include a fluorescent plate to translate the scattered electrons into visible data, and as a result of all of the intricacies of electron microscopy, these microscopes tend to be bulky and finnicky in operation.

TRANSMISSION ELECTRON MICROSCOPY

In 1931, two German electrical engineers, Max Knoll and Ernst Ruska, succeeded in creating the first transmission electron microscope (TEM) (6). The instrument had essentially three components: a source of electrons, a series of lenses that directed the electrons through the specimen and to the detector, and equipment to interpret the electron signature (7). Similar to the way a light microscope displays a shadow where light could not pass through the specimen, the image produced via TEM shows relative levels of transmission of electrons throughout the specimen. “Darker” areas are more electron opaque while “lighter” areas are less so.

Unlike visible light which has a longer wavelength and is thus less energetic, electron beams tend to shred up lighter weight atoms resulting in large levels of scatter and a less contrasted image (3). To work around that, scientists must “stain” the specimen with heavier elements such as uranium, lead, and/or osmium (3). Though this allows for higher quality images, the staining process only adds to the list of difficulties of using TEMs. The microscopes are large, expensive, and difficult to operate and maintain. Suitable specimens must be able to withstand the complicated preparation process and vacuum imaging chamber, and the images produced are colorless. And finally, the stains result in a residue contaminated by heavy metal toxins that are difficult to dispose of properly.

SCANNING ELECTRON MICROSCOPY

As an alternative to the TEM, another German physicist, Manfred von Ardenne, described and produced the first images using a scanning electron microscope (SEM) in 1940 (6). The microscope was smaller than the TEM because it recorded electrons that bounced off the surface (secondary electrons) of the specimen with detectors placed closer to the source than the target (8). This is also what makes SEM images look three dimensional because rather than projecting the electron signature onto a single flat surface, the SEM measures electrons that travel at all angles and combines it to form an image with variable depth (3).

SEMs are also more amenable to researchers because the specimen preparation process is less involved. While specimens for TEM require extremely thin slicing and treatment with stains, SEM specimens only need a thin layer of conductive coating such as a gold film before being placed in the vacuum container, a process not even necessary if the electron beams are strong enough.8 The elimination of destructive preparation techniques has allowed researchers to image larger objects such as insects or small mechanical parts (3). The images produced show such fine details of everyday objects in new ways that they at times seem alien. The microscope is still expensive and needs to be precisely configured for optimal results, but overall, SEMs are easier to use compared to other forms of electron microscopy.

ATOMIC LEVEL MICROSCOPY

As if intracellular imaging weren’t impressive enough, the 1980’s brought the invention of the scanning tunneling microscope (STM), which has the ability to view individual molecules and atoms. This level of magnification grew out of a desire to describe the inner workings of the atom. Like electron microscopy, it relies on the wave nature of electrons (9). The first STM was built in 1981 by Swiss physicists Gerd Binnig and Heinrich Rohrer and was used to study the topography of a gold surface; it worked by measuring the level of electron tunneling at different points along the surface (9). STM relies on tunneling, a quantum mechanical phenomenon in which electrons have some probability of traveling through an impermeable surface, something unexplainable by classical mechanics. What’s useful about tunneling is that it is highly sensitive to distance, specifically, atomic level distances.

The STM operates with an extremely fine pointed probe positioned extremely close to the sample surface (3). Voltage applied to the tip allows for electrons to tunnel to the surface and the number of electrons that make it across the gap is correlated with the distance between the tip and the surface (9). The image produced by all the data is a topographical map of relative “heights,” which is useful because it can determine the atomic structure of the surfaces of different substances. STM has been used to investigate the arrangement of atoms of different metals and crystals and the details of absorption and diffusion of various gases on metal surfaces (9). The advantage of STM over other forms of electron microscopy, beyond its resolution, is that tunneling can take place in a variety of environments and does not need an external source of electrons or lens to focus the beam (3,9). This eliminates much of the specificity involved in undertaking electron microscopy and vastly opens up the domain of imageable surfaces. In fact, STM has been performed in water, ionic solutions, and even insulating fluids that wouldn’t allow electrons to travel conventionally (9).

As with any technology, there are complications that come with using STM. First, the STM setup is still rather complicated since the probe is extremely sensitive. A series of springs and magnets are used to counteract outside disturbances, and the movement of the probe is controlled via the piezoelectric effect where applied current generates compression or expansion of a material (3). The construction of the tip is also problematic because it is only one atom in width. This is accomplished by precisely manipulating extremely strong electric fields to shave off excess atoms. Despite the intricate nature of the STM equipment, the versatility of the probe makes it one of the most powerful imaging tools for modern scientists.

CONCLUSION

Microscopy has come a long way from its humble optical beginnings. Though born out of human curiosity and the desire to view the invisible world lurking all around us, microscopy has been instrumental for scientific and societal advancement. Being able to view bacteria and other pathogens validated germ theory allowing for the development of antibiotics and other therapies that have vastly improved the quality of life over the last century. Being able to view chemical reactions at the atomic level has advanced the efficiency of the chemical industry. And the recently awarded 2017 Nobel Prize in Chemistry was for biomolecular imaging techniques that have allowed for real time observation of biochemical processes.10 Microscopy will always be integral to scientific discovery, and the future of imaging techniques will undoubtedly have far reaching benefits for all humanity.

Kelvin Li ’21 is a freshman in Wigglesworth Hall.

WORKS CITED

[1] Singer, C. J. R. Soc. Med. 1914, 7, 247- 268.

[2] Walker, B. H. In Optical Engineering Fundamentals, 2nd ed.; SPIE Press: Bellingham, Wash, 2008; pp 5-11, 113-116.

[3] Croft, W. J. In Under the Microscope: A Brief History of Microscopy; Weiss, R. J., Ed.; Series in Popular Science; World Scientific Publishing Co.: Singapore, SG, 2006; 5, pp. 5-13, 57-81, 105-112.

[4] In A Dictionary of Physics; Oxford University Press: Oxford, UK, 2014; 7.

[5] Optical Abberations. https://www. olympus-lifescience.com/en/microscope-resource/primer/anatomy/ aberrations/ (accessed Sept. 9, 2017).

[6] Bradbury, S. et al. Electron Microscope. Britannica Academic [Online], Aug. 13, 2017. http://academic. eb.com (accessed Sept. 9, 2017).

[7] Bradbury, S. et al. Transmission Electron Microscope (TEM). Britannica Academic [Online], July 22, 2011. http://academic.eb.com (accessed Sept. 9, 2017).

[8] Bradbury, S. et al. Scanning Electron Microscope (SEM). Britannica Academic [Online], May 17, 2016. http:// academic.eb.com (accessed Sept. 9, 2017).

[9] Quate, C. F. Scanning Tunneling Microscope (STM). Britannica Academic [Online], Aug. 13, 2017. http:// academic.eb.com (accessed Sept. 9, 2017).

[10] Press Release: The Nobel Prize in Chemistry 2017. https://www.nobelprize.org/nobel_prizes/chemistry/ laureates/2017/press.html (accessed Oct. 8, 2017).

By: Connie Cai 

Since 2004, there have been 67 anti-evolution education bills introduced by local governments in the United States (1). Three of those bills have been approved in Mississippi, Louisiana, and Tennessee. These laws make it legal for public school teachers to criticize the theory of evolution—as well as other politicized topics like climate change—and teach alternative explanations to evolution. The most popular of these alternate explanations is intelligent design, or the belief that natural selection cannot by itself create as complex animals as we observe. The success of this legislation hinges upon the fact that today’s debate about evolution in schools is not so much that creationism should be taught over evolution, but rather, that teachers should be allowed to provide alternatives.

This shift in argument has allowed anti-evolution legislation to successfully gain a hold in our education system. The introduction of these regulations and the way they frame the evolution debate are part of a movement that Nick Matzke, former Public Information Project Director at the National Center for Science education, dubs “stealth creationism” (1). The proposed bills, he says, attempt to distance themselves from any potential religious motivations or undertones; instead, they frame their argument as providing critical analysis of contentious science topics (1). At its core, the stealth creationism movement argues that evolution is just a theory and that students should be allowed to debate its merits.

However, treating evolution as “just a theory” undermines the validity of American science education by challenging one of the fundamental and overwhelmingly evidence-supported tenets of biology. Moreover, it compromises students’ understanding of the scientific process—how evidence is collected, synthesized, and used to create the basic theories through which we understand our world. As James Williams, a science instruction educator, states, “Theories such as gravity [or] evolution are not hypotheses in want of further evidence, but rather the sturdiest truths and descriptions of how the material world works that science has to offer” (2). How the kids of today learn and understand science is crucial for our society’s scientific progress; teaching them alternatives to a theory as well-developed as evolution demonstrates to kids that even facts can be challenged by opinion.

EVOLUTION IN CLASSROOMS

The stealth creationism movement is the most recent development in the long history of evolution in the classroom. In the 1920s, the teaching of evolution was banned in most states. During the infamous 1925 Scopes Monkey Trial with Clarence Darrow and William Jennings Bryan, the American Civil Liberties Union (ACLU) attempted to challenge the bans. Though the trial did bring the topic of science education to the nation’s attention, the ACLU was unsuccessful. It was not until 1968 that the Supreme Court ruled that bans on teaching evolution in the classroom were unconstitutional. More recently, a United States federal court ruled in the 2004 Kitzmiller v. Dover Area School District case that teaching intelligent design was unconstitutional because intelligent design could not be separated from its creationist and religious precedents (3). In that court case, the Dover Area School District required high school teachers to teach intelligent design through a textbook called Of Pandas and People alongside evolution. In contrast, the aforementioned laws in Tennessee, Louisiana, and Mississippi do not require teachers to teach intelligent design, but rather protect their right to do so in the classroom.

The support for intelligent design and other evolution alternatives has had a largely religious base. For many fundamental Christians that grow up in communities where the line between church and state is often hazy, it is no wonder that the topic of evolution—which is taught in the last years of high school after years of deeply ingrained religious teachings—does not settle well. While these communities form the basis of voter support for anti-evolution regulation, political groups and think tanks like the Discovery Institute take that support and lobby on behalf of the stealth creationism movement. The Discovery Institute is a secular think tank, but in their mission statement, the Institute writes that it supports the “role of faith-based institutions in a pluralistic society” (4). The Institute funds intelligent design research and educational programs; for them, protecting intelligent design is a question of academic freedom and free speech. The logic of anti-evolution legislation follows similar premises—stealth creationism’s success relies on framing the argument as one of academic freedom. However, a debate on the validity of evolution is not truly academic freedom. Academic freedom applies to the realm of what is true or of seeking what is true; academic freedom is not a space for unsubstantiated data.

SCIENCE AND SOCIETY

Allowing a debate on evolution under the misguided assumption of academic freedom has dangerous consequences. In a study conducted by Technical University Dortmund, researchers found a strong correlation between “acceptance of science” and “acceptance of evolution” (2). This illustrates the strong tie between what we teach and how we understand the world; additionally, the research stresses the importance of having a well-developed and accurate science curriculum if we want a society that trusts science again. In addition, the debate surrounding evolution fits into a much larger cultural context and the growing alternative facts movement. Recently, more politicians have been vocal about their distrust of the scientific community. Current political dynamics seem to be moving away from evidence and data-based policies; a clear example of this is persistent climate change denial and the refusal to enact legislation regulating fossil fuel consumption. In these times, how we teach science and how we encourage scientifically literate citizens are becoming ever more pertinent questions. Moreover, the mounting skepticism from politicians and the public has mobilized the scientific community. In April 2017, the first March for Science was held to address these issues; over one million people across the world participated in the rallies that sought to celebrate science and the role that science has in our society, as well as to call for more evidence-based policymaking and science funding.

The March for Science, while a prominent rallying symbol for the scientific community, also demonstrates how politically charged science has become. Based solely on evidence, evolution is undebatable; politically, evolution is a hotly contested and controversial topic. Because it has become politicized, addressing the issue of evolution is not one that can easily be fixed by presenting the multitude of supporting data for evolution.

Yet fixing our current science curriculum and confronting the recently passed legislation are extremely important tasks to undertake. Allowing the laws to stand as is will have potentially dangerous consequences for the role of scientific truth in our society; as of now, the success of the bills in certain states has inspired copycat bills elsewhere.

SHAPING EDUCATION

Though it will be difficult to have an immediate effect on the current political climate, certain proposed changes may increase the acceptance of evolution and other contested science topics. First among those changes is teaching evolution at a younger age. Currently, evolution is not formally taught until high school, and in the eyes of many researchers and science instructors, that is too late. Kids learn about other aspects of biology, but evolution is, for myriad reasons, postponed. Williams, a science education instructor, states that “To me, [to hold off on teaching evolution] is odd—it’s like trying to teach chemistry but not putting atoms at the center (2). The argument for teaching evolution sooner is that it helps introduce the concept in students’ minds and prevents them from forming misconceptions about evolution. After all, most of the students who come in not believing in evolution have never been formally taught it; what they know about evolution is given to them by their parents or religious communities. As Dittmar Graf, a researcher at the Technical University, explains, “When somebody has a misconception in science, if it’s embedded, it’s incredibly difficult to change” (2).

Secondly, it is important to recognize stealth creationism for what it is and understand that intelligent design supporters are relying less on religious arguments. It is crucial, in this case, to make clear the distinction between science and nonscience in the classroom: true science must be rigorous, widely accepted, and evidence-based. In a statement made by the InterAcademy Panel (a global organization that represents numerous national science organizations), countries agreed to make “decision-makers, teachers, and parents educate all children about the methods and discoveries of science” and that there were clear “evidence-based facts about the origins and evolution of the Earth and of life on this planet” (2).

Building up trust at the intersection of politics, science, and society is a difficult but paramount task for our nation’s progress. It all begins with a solid foundation in the classroom—controlling what is taught in the classroom shapes the minds of future generations. Though the debate surrounding evolution has always been seen as a contest between science and religion, in our current times it is shaping into a debate about what constitutes scientific truth and the collective societal understanding of science. Change may be slow, but the truth matters—and everyone deserves to know the truth. Connie Cai ’21 is a freshman in Grays Hall.

WORKS CITED

[1] Jaffe, E. The Evolution of Teaching Creationism in Public Schools. The Atlantic [Online], Dec. 20, 2015. https://www.theatlantic.com/education/archive/2015/12/the-evolutionof-teaching-creationism-in-publicschools/421197/ (accessed Sept. 4, 2017).

[2] Harmon, K. Evolution Abroad: Creationism Evolves in Science Classrooms around the Globe. Scientific American [Online], Mar. 3, 2011. https://www.scientificamerican.com/article/evolution-education-abroad/ (accessed Sept. 4, 2017).

[3] National Center for Science Education. Kitzmiller v. Dover: Intelligent Design on Trial. https://ncse.com/ library-resource/kitzmiller-v-dover-intelligent-design-trial (accessed Sept. 20, 2017).

[4] Discovery Institute. https://discovery.org/id/ (accessed Sept. 20, 2017).

[5] Matzke, N. Science. 2016, 351(6268), 28-30.

(The following notes relate to the images in the print copy of the article.)

Fig 1. These are embryo drawings of Ernst Haeckl, one of the first developmental biologists. The similarities he notices between the embryos of different species was used to support the theory of evolution, as it demonstrated shared ancestry between different species and a common evolutionary theory. (Image from Wikimedia Commons)

Fig 2. Proponents of intelligent design often use the watchmaker analogy. A watch (a working system) must be designed by a watchmaker; similarly, nature (a working system) implies a designer. (Image from Wikimedia Commons)

By: Michelle Koh

What is a cyborg? One might imagine Terminator-esqe half-human, half-machine hybrids or other creatures with fantastic mechanical augmentations, but we must direct our attention down to the cellular level—to cyborgian beings that are far smaller. Despite these cyborgs’ underwhelming size, UC Berkeley researcher Kelsey Sakimoto and his fellow researchers of Professor Pei-dong Yang’s lab have engineered a new biohybrid bacteria that may make a formidable impact on the solar fuel industry.1 These originally non-photosynthetic organisms are able to grow their own tiny semiconductor “solar panels” to harness solar energy and store it in the chemical bonds of acetate, an essential natural and industrial building block (1).

WHAT IS SOLAR FUEL?

According to the Royal Society of Chemistry, more energy is delivered to Earth in one hour by the sun than all the energy that we consume through fossil fuels, nuclear energy, and other renewable sources of energy in a year (2). Plants and other photosynthetic organisms have mastered the process of capturing and storing this solar energy in chemical fuels or “solar fuels” (2). Since the 1950s, scientists have strived to mimic these processes to create more sustainable alternatives to traditional energy sources such as fossil fuels (2). Unlike the energy generated by other sources of renewable energy, like photovoltaic cells and wind turbines, the physical nature of solar fuels means that they can be much more easily stored and transported through existing distribution networks and methods.

Acetate and other carbon-based solar fuels can be used as feedstock, or raw material, for the production of many products such as fertilizers, pharmaceuticals, and plastics (2). Currently, the petrochemical industry produces much of the feedstock for these industries. However, solar fuel-derived feedstock, in addition to being more renewable, reduces the harmful greenhouse gas emissions.

PHOTOSYNTHETIC BIOHYBRID SYSTEMS

Humans have developed incredible scientific and technological capabilities so far as to not only replicate some of the most complicated biological and chemical systems in nature but also surpass them in efficiency. Nevertheless, some processes, like the conversion of CO2 and other small atmospheric molecules to more complex organic molecules, have been more difficult to mimic (3).

The reduction of, or the addition of electrons to, CO2 is surprisingly difficult. Electrons must be transferred from some catalyst, or an electron carrier, to CO2 , and new carbon-to-carbon bonds must form (3). Furthermore, as each process and chemical reaction in the biological world is highly specific in its reactants and products, scientists also have to replicate the high-accuracy selection of a single product (3). Attempts to reproduce these processes in the lab have often ended in tangles of chemical problems that seem to contradict one another, yet biological organisms have evolved so that the cell is able to incubate and facilitate a vast number of diverse reactions through a delicately-regulated chemical environment.

As a result researchers have developed photosynthetic biohybrid systems (PBSs) to take advantage of the existing biological systems that have been developed so elegantly through evolution (3). By combining these systems with high-efficiency inorganic light harvesters, they are able to enhance or induce photosynthetic capabilities in organisms (3). The key challenge of this field has been smoothly integrating the biotic and abiotic components of the PBSs. Some PBSs feed electrons collected by an inorganic light harvester to the biological part of the system, though engineering and producing nanowire arrays and intricate carbon cloths to do so can be costly (4). Other researchers have developed PBSs by isolating specific enzymes, such as hydrogenases, and combining them with semiconductor nanoparticles (4). However, whole-cell PBSs are favored due to their self-replication and self-repair capabilities (4).

Sakimoto et al., on the other hand, have been able to engineer microorganisms that not only facilitate CO2 reduction, but also synthesize their own inorganic light harvester materials (3). Sakimoto’s team discovered that the introduction of Cd2+ (cadmium) ions to initially non-photosynthetic Moorella thermoacetica bacteria can induce the bio-precipitation of cadmium-sulfide (CdS) nanoparticles on the cell surface (4). The growth of these semiconductor light harvesters is able to transform the M. thermoacetica bacteria into highly efficient photosynthetic systems, producing products that are 90% acetic acid and 10% biomass (4).

Since the bacteria are able to produce their own inorganic semiconductor light harvester particles, Sakimoto et al.’s new PBS is cost-effective (4). The complex micro-fabrication techniques, high-purity reagents, and high-temperature processes are essential in synthesizing the semiconductor components in PBSs, but they are incredibly energy and resource intensive (4). Aside from the initial set-up of the system, Sakimoto et al.’s system requires very low maintenance, as the bacteria are able to remake the CdS particles even after the particles degrade (4).

CYBORGIAN EVOLUTION

Sakimoto and colleagues aim to experiment with other semiconductor particles and bacterial species in order to optimize the efficiency of their PBS (4). Since cadmium sulfide is highly toxic, they hope to replace these nanoparticles with other less toxic semiconductor materials such as silicon (4). As other researchers strive to develop PBSs that not only reduce CO2 but also complete other crucial biological processes such as N2 fixation, Sakimoto et al.’s discovery may signify the advent of a new cyborgian evolution (3).

Michele Koh ’21 is a freshman in Holworthy Hall.

WORKS CITED

[1] Cottingham, K. Cyborg Bacteria Outperform Plants When Turning Sunlight into Useful Compounds. https://www. acs.org/content/acs/en/pressroom/ newsreleases/2017/august/cyborg-bacteria-outperform-plants-when-turning-sunlight-into-useful-compounds-video.html (accessed Oct. 1, 2017).

[2] Royal Society of Chemistry. Solar Fuels and Artificial Photosynthesis: Science and Innovation to change our Future Energy Options; Royal Society of Chemistry: Cambridge, U.K., 2012; 4-11.

[3] Sakimoto, K., Acc. Chem. Res. 2017, 50, 476-481.

[4] Sakimoto, K. Science. 2016, 6268, 74- 77.

By: Julia Canick

In a world that places a high premium on happiness, the prospect of coping with a mental illness as debilitating as depression can be frightening. Scarier still, general practitioners diagnose only about half of major depressive disorder (MDD) cases (1). In an effort to raise this unacceptably low rate of success, Andrew Reece and Christopher Danforth (of Harvard University and University of Vermont, respectively) turned their attention to an unlikely source of information: social media.

In a recent study, the two researchers combined different computational methods, including color analysis, metadata components, and face detection technology, to analyze 43,950 Instagram photos from 166 participants (2). While previous predictive screening methods had successfully analyzed online content to detect some health conditions, they had all relied on text, not visual posts. This study was different: the analysis identified hallmarks of depression not through the content itself, but through a few key qualities about what was posted.

Some of the results were not shocking: Reece and Danforth found that depressed individuals were more likely to post photos that were bluer, grayer, and darker than those posted by their non-depressed counterparts (2). Furthermore, depressed posters were more likely to use a black-and-white filter (like Inkwell) on their photos, while people not afflicted with the disorder were more likely to use filters that gave their photos a warmer tone (like Valencia) (3). This is certainly a reasonable finding; previous studies had pointed to a general perception that darker and grayer colors were associated with a negative mood (4).

Another finding was more unforeseen: depressed Instagrammers were more likely than non-depressed ones to post photos with faces—with the caveat that they had, on average, fewer faces per photo (2). Depression is strongly associated with lowered social activity, so the higher frequency of posts that featured faces is counterintuitive (5).

These findings are fascinating on their own, but the most astounding part is, perhaps, the marked increase in the percentage of successful depression diagnoses made: the computer model correctly identified 70% of the cases of depression in the study, a marked increase from the 47.3% success rate of general practitioners (1,2). The system was even able to recognize markers of depression before the date of the first diagnosis, an advance that suggests that further refinement of this algorithm may lead to better preventative measures for major depressive disorder (2).

The implications for the success of a photo analysis model like this one are staggering. The generation of information using entirely quantitative means, instead of human participation, eliminates subjective opinion, and, with it, the natural propensity for observer bias. Furthermore, the speed and automation of the diagnosis process can accelerate the search for treatment, and could give rise to future programs where doctors would, with patients’ permission, receive notifications if their patients’ Instagram posts raise red flags.

This data model isn’t perfect—for example, a major concern is that patients who are officially diagnosed with MDD may identify with the label, and therefore post content in accordance with their self-image (6). This presents the potential issue of patients perpetuating stereotypes associated with their diagnoses because they tell themselves they “must act” in a manner in keeping with the general image of MDD, instead of taking steps to break the stigma accompanying their illnesses. However, the benefits of this algorithm far outweigh the possible downfalls; Instagram garners nearly 100 million posts per day, and the utilization of these photographs as data points for analysis of mental health would be revolutionary for the advancements of both diagnostic tools and therapeutic accessibility (7)

Gray days often call for gray photos—and, now, there’s a way to harness that observation to make MDD diagnosis and treatment more accurate and accessible for those who are struggling.

Julia Canick ’18 is a senior in Adams House concentrating in Molecular and Cellular Biology.

WORKS CITED

[1] Mitchell, A. J. et al. The Lancet. 2009, 374(9690), 609-619.

[2] Reece, A. G.; Danforth, C. M. EPJ Data Science. 2017, 6(1), 15.

[3] Brown, J. When You’re Blue, So Are Your Instagram Photos. EurekAlert! [Online], Aug. 7, 2017. https://www. eurekalert.org/pub_releases/2017-08/ uov-wyb072717.php (accessed Sept. 24, 2017).

[4] Carruthers, H. R. et al. BMC Med. Res. Methodol. 2010, 10(1), 12.

[5] Bruce, M. L.; Hoff, R. A. Soc. Psychiatry Psychiatr. Epidemiol. 1994, 29(4), 165- 171.

[6] Cornford, C. S. et al. Fam. Pract. 2007, 24(4), 358-364.

[7] Instagram. https://instagram-press.com (accessed Sept. 24, 2017).

By: Alex Zapién

It has been over a year since the New Horizons spacecraft approached Pluto in July 2015. Now, New Horizons continues its path into space much like New Frontier, the project responsible for New Horizons, continues its progress. New Frontier is also responsible for Juno, the space probe that successfully entered Jupiter’s orbit in July of 2016, and for OSIRIS-REx (1). The OSIRIS-REx (The Origins, Spectral Interpretation, Resource Identification, and Security- Regolith Explorer) spacecraft was sent by the National Aeronautics and Space Administration (NASA) to the asteroid Bennu this fall in order to obtain and return asteroid samples for analysis back here on Earth (2).

The OSIRIS-REx spacecraft was launched on September 8, 2016 from Cape Canaveral, Florida and is scheduled to reach Bennu in 2018 (2). The mission’s objective is to retrieve, analyze, and return a carbonaceous asteroid sample in order to gain a deeper understanding of the minerals and organic material found in Bennu and other Near Earth Objects (NEOs) (2). Analysis of the collected data will allow scientists to precisely map the asteroid’s orbit and measure the orbit deviation caused by non-gravitational forces out in space, otherwise known as the Yarkovsky effect (3).

Bennu was chosen out of an initial pool of 500,000 known asteroids and 7,000 NEOs. Researchers narrowed down the pool based on the object’s proximity to Earth, size, and composition (3). The distance from the object to Earth had to be between 0.8 astronomical units (AU) (about 75 million miles/120 million km) and 1.6 AU (about 150 million miles/240 million km) and would ideally have an Earth-like orbit with inclination and eccentricity to make the journey to the object more accessible. In addition, the size of the asteroid was also highly considered. The smaller the asteroid’s diameter, the more rapidly it rotates. Asteroids with diameters less than 200 meters rotate so rapidly they eject loose material from the surface, which would pose a serious hazard for the OSIRIS-REx spacecraft upon contact (3). The ideal asteroid would have a diameter of about 500 meters, which is exactly the size of Bennu’s diameter. Finally, the ideal asteroid needed to have the properties of a primitive, yet extremely old asteroid. This meant having a carbon-rich composition that had not been significantly changed in nearly 4 billion years. The composition of the asteroid is determined based on how the asteroid reflects the Sun’s light. Asteroids that fit this description usually contain amino acids and original material of gas and dust from solar nebula that collapsed to form the solar system, which can tell us about the building blocks of life on Earth as well as the conditions at the solar system’s birth (1, 3).

With the criteria, the choice was narrowed down to five candidates with Bennu ultimately being chosen. Interestingly, Bennu satisfied every criterion but one: distance. Researchers decided choosing Bennu would be more appropriate, as it comes within only 0.002 AU (about 186,000 miles/300,000 km) from the Earth every six years, much closer than the ideal range of 0.8 and 1.6 AU (3). This proximity gives Bennu a high probability of impacting the Earth within the next 200 years. Indeed, NASA scientists have calculated that the odds of Bennu starting an orbit (in the early to mid-2100s) that would lead to a collision with the Earth in the late 22nd century is 1 in 2,700, making it a fascinating NEO (4).

Ultimately, it was Bennu’s composition, size, and hazardous orbit that made it a perfect and accessible NEO.3 If successful, the OSIRIS-REx spacecraft will return a sample to Earth in 2023. The OSIRIS-REx mission will improve our understanding of both the formation of the solar system and the quality and trajectories of asteroids that could collide with Earth (2). We will be able to devise future strategies to mitigate possible Earth impacts from celestial objects, and, more importantly, we will gain a greater understanding of our planet and our solar system. There is no doubt that we will reach a new frontier in science.

Alex Zapién ‘19 is a sophomore in Cabot House, concentrating in physics.

WORKS CITED

[1] New Frontiers Program. https://discoverynewfrontiers.nasa.gov/index.cfml (accessed Sept. 26, 2016).

[2] OSIRIS-REx. https://www.nasa.gov/osiris-rex (accessed Sept. 26, 2015).

[3] OSIRIS-REx: Asteroid Sample Return Mission. http://www.asteroidmission.org/why-bennu/ (accessed Sept. 27, 2016).

[4] Wall, Mark. http://www.space.com/33616-asteroid-bennu-will-not-destroy-earth.html (accessed Sept 27, 2016)

By: Alex Zapién

On September 1, 2016, the Space Exploration Technologies Corporation (better known as SpaceX) lost one of its 70-meter (229-foot-tall) Falcon 9 rockets when it unexpectedly exploded during a simulated countdown on a launch pad in Cape Canaveral, Florida (1). The incident occurred two days before its intended launch, and eyewitness testimonies described the event as “a series of explosions that could be felt for miles” (2).

While the cause of the explosion is unknown, SpaceX Founder, CEO, and Lead Designer Elon Musk believes “an anomaly on the pad” may have occurred when the rocket was being filled with propellant (1). Industry officials say it could take several months to determine the exact cause and even more to take remedial action (2). The rock-
et was unmanned, so there thankfully were no injuries; however, the aftermath of the explosion has worsened the backlog of delayed commercial launches and will likely complicate the company’s pursuit of future government contracts (2). The mishap has also raised questions about the reliability of the Falcon 9 booster, which was slated to haul cargo and astronauts to the International Space Station in the future (3).

SpaceX had been trying to go beyond its mission of solely building revolutionary space technology by also directly aiding in the transportation of Facebook’s six-ton satellite AMOS-6. However, the satellite was also lost in the incident (2). AMOS-6, valued at approximately $200 million, was part of a project led by Facebook, Eutelsat, and Spacecom. Not only would AMOS-6 have been the first satellite Facebook put in orbit, but it would have also provided direct internet access to people in sub-Saharan Africa (4). Following the incident, Facebook Founder and CEO Mark Zuckerberg expressed his frustration, saying he was “deeply disappointed to hear that SpaceX’s launch failure destroyed [the] satellite that would have provided connectivity to so many entrepreneurs and everyone else across the continent” (4). Despite the catastrophic results, Facebook has remained committed to connect everyone worldwide and they are currently developing other technologies that will provide the people of Africa with the same opportunities AMOS-6 would have provided (4).

The explosion of the rocket and its commercial interest also deeply frustrated Elon Musk, sparking him to work for an investigation. On September 9, 2016, more than a week after the incident, Musk openly asked the public and directly asked the National Aeronautics and Space Administration and the Federal Aviation Administration for help (5). Public responses have proven helpful. Responses include videos of the Falcon 9 rocket explosion, some of which appear to show an object hitting the rocket; however, there is no further evidence to corroborate this. Preliminary results from an investigation have also pointed to a rupture in the cryogenic helium system (6). Overall, the case has proven to be rather perplexing and besides the video evidence, there are no further leads. Musk claims that “this is turning out to be the most difficult and complex failure we [SpaceX] have ever had in 14 years.”

As of October 1, 2016, the Falcon 9 investigation has not concluded, but SpaceX has hopes for another launch, a resupply mission to the International Space Station. Dates are tentative, but SpaceX Chief Operating Officer Gwynne Shotwell mentioned the “November timeframe” as time to return to space.6 Although focused on addressing the issues behind the anomaly, SpaceX remains committed to its mission of revolutionizing space technology and serving the world.

Alex Zapién ‘19 is a sophomore in Cabot House, concentrating in physics.

WORKS CITED

[1] Malik, Tariq. Scientific American. http://www.scientificamerican.com/article/spacex-falcon-9-rocket-explodes-on-launch-pad-in-florida/ (accessed Sep. 29, 2016).

[2] Pasztor, Andy. The Wall Street Journal. http://www.wsj.com/articles/spacex-rocket-test-hit-by-explosion-1472738051 (accessed Sep. 29, 2016).

[3] Chang, Kenneth et al. The New York Times Science. http://www.nytimes.com/2016/09/02/science/spacex-rocket-explosion.html?_r=0 (accessed Sep. 30, 2016).

[4] Letzter, Rafi. Business Insider: Science. http://www.businessinsider.com/spacex-falcon9-explosion-facebook-satellite-amos6-2016-9 (accessed Sep. 30, 2016).

[5] Cofield, Calla. Space. http://www.space.com/34029-elonmusk-seeks-help-solving-rocket-explosion.html (accessed Sep. 30, 2016).

[6] Mack, Erick. News Atlas. http://newatlas.com/spacex-falcon-9-explosion-tentative-launch-date/45704/ (accessed Oct. 1, 2016).

By: Kristine Falck

The state of the globe today puts the world’s future in question. We have a burgeoning population heading on 7.4 billion people, an 80% reliance on fossil fuels, and an imminent fresh-water shortage. By 2035, current estimates predict world energy consumption to increase by 50% as well as world water consumption by over 85% (1). What is also of concern, is the fact that over 90% of current energy producing methods are classified as water intense (1). This is alarming, especially in light of the highly interdependent relation between water and energy. In other words, the world is headed for crisis due to these pinnacle challenges. There is immediate need for a shift towards the renewable-energy sector, in addition to a feasible solution to looming water scarcity.

With both an impending fresh water shortage and energy availability predicament, harnessing the world’s ocean tidal power as a source of both power and water for desalination could prove to be of immense value in the near future. With thousands of miles of shoreline around the world that have constant exposure to unharnessed wave energy, the ocean is an untapped source of clean energy. The total estimated ocean power is about 10,480,000 MW, yet only very small amounts of this estimated power are used (about 8000 MW, mainly in France, Canada, Australia, and the US) (2). Capturing this tidal energy could significantly augment global energy production, and diminish reliance on harmful fossil fuels. Since already some 2.8 billion people—a number that is expected to grow to 3.5 billion in the next decade— worldwide suffer from water scarcity, production of clean water is an imminent problem the world must address (1).

THE FOSSIL FUEL STATUS QUO

Not only are fossil fuels leading our demise in climate change, but they also comprise the largest consumption of the fresh water sector. Currently, the US derives 90% of its electricity from thermoelectric power generation plants (1). This in turn account for a staggering 45% of the U.S.’s total water withdrawals including freshwater sources like lakes and rivers, and saline sources, such as oceans and estuaries (3). The majority of these plants rely on what is called “once-through” cooling technology. Essentially, millions of gallons of water are withdrawn daily, before being dumped back at a higher temperature into whatever body of water they were withdrawn from. In addition, the production and refining process of oil requires lots of water (estimated that the US withdraws 2 billion gallons of water each day to refine nearly 800 million gallons of petroleum products like gasoline) (3). Unfortunately, corn-based ethanol, touted as an eco-friendly alternative fuel, is not water-friendly either; 324 gallons of water use are attributed to the production of a single gallon of ethanol, meaning it uses more than gasoline (which requires 3-6 gallons) (4). In essence, the production of both clean water and energy is an increasingly urgent problem.

The large use of water is particularly concerning because fresh water only comprises a mere 2% of the world’s water supply. These concerns have grown because of recent high profile droughts: California experienced its fifth straight drought year, and even British Columbia, Canada, a region blessed with a natural abundance of fresh water, was confronted with a stage 3 drought, drawing attention to the severity of the issue at hand. What can we do to save our dwindling fresh water supply?

TIDAL POWER

With both an impending fresh water shortage and energy availability predicament, harnessing the world’s ocean tidal power as a source of both power and water for desalination, could prove to be of immense value in the near future. Capturing tidal energy could serve to significantly augment global energy production, and diminish reliance on harmful fossil fuels. Despite its availability, tidal power technology is only currently in usage in Perth, Australia. Yet, it is capable of being installed in other highly turbulent tidal coastlines such as Alaska, Washington, California, British Columbia, Scotland, and the Chilean coast.⁵ The ocean is at our disposal as an untapped beacon of energy, and will serve as an important component to our strategy in addressing our global energy crunch.

DESALINATION

Since 98% of the world’s water supply is saltwater, it is evident that the desalination of seawater will become instrumental to fulfilling the world’s water needs (9). As John Lienhard, director of the Center for Clean Water and Clean Energy at MIT said, “As coastal cities grow, the value of seawater desalination is going to increase rapidly, and we will see widespread adoption” (6).

DUAL PURPOSE PLANTS

Combining desalination and tidal power solves these problems, and as like everything else in life, it comes down to its economics. By developing a single integrated facility comprising of both a desalination plant and an energy generation facility, significant monetary benefits could be achieved through integrated planning, shared optimized infrastructure, and lower capital costs. Utilizing the high pressurized water already present in tidal energy plants to desalinate water through reverse osmosis, the costs of desalinating water would drop significantly, as nearly 60% of desalination’s high operating costs is due to the creation of the highly pressurized water (7).

Ocean power generators, which capture the energy of waves and tidal motion, have the potential to produce a significant amount of electricity. Carnegie Wave Energy in Australia has designed a technology called CETO, which is able to capture nearly 70% of transmitted tidal energy (7). A coal power plant in comparison is a mere 42% efficient (7). This means these combined plants will also be extremely efficient in their energy conversion– another benefit. The leading edge 3MW CETO 5 technology employs three 36-foot wide steel buoys tethered to the ocean floor (7). When a wave crashes and the buoys bob, the seabed pumps are activated, and water is thrust at high pressure through a subterranean pipe to a power station on land (8). The surging water, in turn, spins hydroelectric turbines that activate a generator, and then undergo desalination through reverse osmosis once leaving the generator (8). Because the water is being forced into the power station at such high pressures, it is also able to be desalinated through reverse osmosis, passing through membranes after leaving the generator (8). The efficiency of this system in converting wave energy to electrical energy can reach over 50 percent and is capable of desalinating 50 billion liters of water each year. Other benefits of CETO’s technology includes the fact that buoys can power themselves at a remote location and support a flexible suite of sensors and equipment for maritime security and monitoring off the grid (7).

Carnegie Wave Energy’s CETO 5 technology is a leader of tidal-desalination combined facilities. Their technology is currently in usage in Perth, Australia, and would be capable of being installed in other highly turbulent tidal coastlines (such as Alaska, Washington, California in the United States; British Columbia, Canada; Scotland, and the Chilean coast) (11). These dual-purpose facilities, which utilize tidal power to create energy as well as desalinate water, will prove to be important facilities in the future. By converting ocean wave energy into zero-emission electricity and desalinated water, this integrated facility will indisputably become an economical solution to the world’s imminent water and renewable energy cruses.

Kristine Falck ’20 is a freshman in Straus Hall.

WORKS CITED

[1] United Nations Department of Economic and Social Affairs. http://www. un.org/waterforlifedecade/water_and_ energy.shtml. (accessed Oct. 17, 2016).

[2] United States Geological Survey. http:// water.usgs.gov/watuse/wupt.html. (accessed Oct. 17, 2016).

[3] James E. McMahon and Sarah K. Price. Water and Energy Interactions. https:// publications.lbl.gov/islandora/object/ ir%3A158840/datastream/PDF/view. (accessed Oct. 17, 2016).

[4] Environmental Protection Agency. https://www.epa.gov/sites/production/ files/2015-08/documents/420r10006. pdf. (accessed Oct. 17, 2016).

[5] Harnessing the Power of Waves – Hemispheres Inflight Magazine. (2015). http://www.hemispheresmagazine. com/2015/06/01/harnessing-the-power-of-waves/ (accessed Oct. 17, 2016).

[6] California Turns to the Pacific Ocean for Water – MIT Technology Review. (2014). http://www.technologyreview. com/featuredstory/533446/desalination-out-of-desperation/. (accessed Oct. 17, 2016).

[7] Carnegie Wave Energy – CETO Overview. http://www.carnegiewave.com/ ceto-technology/ceto-overview.html. (accessed Oct. 17, 2016).

[8] Carnegie’s CETO 5 Operational. http:// http://www.wavehub.co.uk/latest-news/carnegies-ceto-5-operational. (accessed Oct. 17, 2016).

[9] Desalination using renewable energy sources. Retrieved August 2, 2015, from http://www.sciencedirect.com/science/ article/pii/0011916494000980

[10] How The Power Of Ocean Waves Could Yield Freshwater With Zero Carbon Emissions. (2013). http://thinkprogress.org/climate/2013/08/30/2554091/ ocean-waves-freshwater/. (accessed Oct. 17, 2016).

[11] Wave-powered desalination pump permitted in Gulf – CNET. http://www. cnet.com/news/wave-powered-desalination-pump-permitted-in-gulf/. (accessed Oct. 17, 2016).

By: Eric Sun

Artificial intelligence (AI) is a hot commodity in the modern world. Machines are now capable of reading and transcribing books, recognizing speech, analyzing big data, playing chess and Go at superhuman levels, and identifying objects through computer vision. Corporate giants like Google, Intel, and Amazon have poured hundreds of millions of dollars into AI research. Research centers and universities have made their own contributions to developing AI. However, some concerns still loom large: Is AI ethical? What are the dangers associated with “intelligent” machines? What kind of trajectory is the research following? I discuss these concerns alongside general artificial intelligence with two members of the Harvard University faculty: Dr. Venkatesh Murthy, a neuroscientist, and Dr. Barbara Grosz, a computer scientist.

Dr. Venkatesh Murthy is a professor of Molecular and Cellular Biology at Harvard. He specializes in neuroscience with an emphasis on information processing and adaptation in neural circuits. He has made significant contributions to the understanding of neural pathways in the olfactory system. Murthy is also interested in artificial intelligence research and teaches a freshman seminar on artificial and natural intelligence.

Dr. Barbara Grosz is the Higgins Professor of Natural Sciences at Harvard. She has made significant contributions to research in natural language processing and multi-agent systems and is currently conducting research in teamwork and collaboration. She teaches the course Intelligent Systems: Design and Ethical Challenges.

What was your path to academia like?

MURTHY: I started out as an engineering undergraduate student in India, but became interested in combining physical sciences and biology for my graduate work in the US. I learned about neural network research and AI during the end of my master’s degree in bioengineering and decided to pursue a PhD in neuroscience with some tangential work on neural networks. For my postdoctoral and early faculty work, I ended up doing purely experimental neuroscience, but recently I’ve rekindled my interest in computational neuroscience.

GROSZ: It was an unusual path. I started out as an undergraduate studying mathematics: there were no undergraduate computer science majors. I was, though, able to take a few courses in computer science, and then went to graduate school in computer science. In graduate school, I focused initially on numerical analysis and then I did some work in theoretical computer science.

Then, thanks to a part-time job at Xerox PARC and a conversation with Alan Kay, I began working in natural-language processing.

At the time, there were many people working on syntax and some on semantics. I was young, brave, and foolish and took on the challenge of building the first computational model of discourse as part of a speech processing project at SRI International. Later, I co-founded the Center on the Study of Language and Information at Stanford, and subsequently went to an academic position at Harvard. I always tell undergraduate students that you don’t need to know what you want to do in your first years of college, but can change paths many times.

What are your research interests?

MURTHY: I work in neuroscience and have an interest in artificial intelligence, but I’m not sure if I would pursue the mathematical, theoretical research in artificial intelligence. But I am very interested in understanding neural pathways in animals through neural networks and seeing if any similarities [to AI systems] exist.

GROSZ: Currently, my research focuses on modeling teamwork and collaboration in computer systems. Prior to this, I worked [for] many years on problems in dialogue processing. Dialogue participation requires more than simply understanding words and sentences; you need to understand the purposes and intentions of the people communicating with one another. This insight led to my working on modeling teamwork and collaboration. In the late 1980s and 1990s, I developed, with some colleagues, the first computational model of collaborative planning. While dialogue is between two people, teamwork often involves a larger number of people. It is much simpler to model the plans of an individual than to model the plans of a group, because teamwork and collaboration are not simply the sum of individual plans. The challenges teamwork raises include such questions as, what information has to be shared for teamwork to succeed? What compels individuals to participate in teamwork? How do you know what each component part is doing? Now, the focus of my research is on using these models of teamwork to build computer systems that improve healthcare coordination, which requires handling what we call loosely coupled teamwork. This work can be applied generally to many situations, including physician-physician networks.

How did you become interested in AI?

MURTHY: As I said, I was studying engineering but, for me, it was not very interesting… I read the books [on artificial intelligence] that everyone reads—Minsky’s Society of Mind and a few others. They presented lots of different ideas about artificial intelligence that were fascinating at that time.

GROSZ: When I was looking for a thesis topic, Alan Kay, the person who invented Small Talk, suggested that I [try] taking a children’s story and retelling it from the viewpoint of a side character. It turns out that this is a very difficult task. Instead, I did some work with Alan Kay on Small Talk and then went to SRI International to work on speech understanding research in the 1970s. For years, I worked with dialogue research and from there, I got interested in collaboration and teamwork, which is a subject that I have pursued for some time now.

What is AI?

MURTHY: That is a very good question. For me, AI has a very different meaning than it might have for some others. I feel that if you have one machine that is very good at one intelligent task, then that is artificial intelligence. For example, if a program can recognize faces very well or better than humans, than that would be artificial intelligence. Or if it could predict behaviors, or if it could discern sounds… Artificial intelligence can just be one very intelligent feature instead of a unit with lots of different complex functions.

GROSZ: AI was, until very recently, purely an academic field of study, which had two complementary goals. People in the field generally chose one of two different kinds of goals: using AI/scientific approaches to model intelligent behavior in humans or developing methods to make computer systems more “intelligent”. Recently, the field has evolved from a purely academic discipline and we are beginning to see increasingly many real-world applications through corporate efforts. It is no longer purely academic, which is great.

Which aspects of AI do you find to be the most promising?

MURTHY: I find the application of artificial intelligence to predicting behaviors in consumer markets very fascinating. Companies like Facebook, Google, and Amazon have amazing capabilities in predicting what a person may be interested in next… Even the behavior of a quirky person, or at least a person who thinks that they are quirky, may be predicted by artificial intelligence sometime in the future. I feel that this is a real possibility. “Even the behavior of a quirky person, or at least a person who thinks that they are quirky, may be predicted by artificial intelligence sometime in the future.”

GROSZ: I think that almost every aspect of AI has promise—promise for changing our lives, promise for affecting what we can do in the world. This ranges all the way from sensory processing—sensing for security, robotics, helping people with hearing disabilities — to complex tasks. Language processing has the potential to help people around the world to communicate through translation, and enables increasing web access. Multi-agent systems methods support teamwork and help people in many ways, from planning and plan recognition to coaching victims of stroke and protecting wildlife areas from poaching. Machine learning is currently big in the news with advances especially in the area of sensory processing. It’s an exciting time for AI.

What are the most important challenges that face AI today?

MURTHY: Right now, we have a lot of data and most people are interested in performing some form of statistical or mathematical analysis of the data—clustering, finding patterns. I’m not sure if we will be able to evolve from that framework… We might become very good at analyzing data but it may take a very long time before we are able to create real intelligence that understands the underlying causes of the observed data.

GROSZ: Two major challenges. One is how to incorporate artificial intelligence into computer systems in a way that they work well with people. Contrary to science fiction, where computer systems are portrayed to be exact replicas of human intelligence, machines don’t need to be replicate exact replicas of human intelligence, but can complement it. Instead, we need to assess where human intelligence falls short and develop computer systems that fill in those gaps and work closely with humans. The other challenge is to build systems that are capable of explaining their decisions to humans. This is not a simple challenge. For example, it is [difficult] for systems using deep neural networks to explain their results. These issues will need to be addressed in the future.

Where do you envision AI to be in 20 years?

MURTHY: Predictions are always very difficult to make and not very accurate. I would imagine that much would be the same as today but more advanced… Machine learning would still be used in research and there would likely be more advanced pattern recognition in artificial intelligence for recognizing items (visual, auditory or other) and predicting consumer behavior.

GROSZ: There is a project at Stanford called the One Hundred Year Study on Artificial Intelligence, colloquially known as AI100, which started about two years ago. Every five years, the Standing Committee for this project, which I currently chair, brings together a group of 15-20 experts in AI along with people who are social scientists or policymakers to assess the field (in light of prior reports) and predict where the field will be in 10-15 years. Our first study panel just issued a report on AI and life in 2030, which I highly recommend. (Access this report at https://ai100.stanford.edu/).

Any closing remarks?

MURTHY: Artificial intelligence is a very interesting field… I would recommend that more people become involved or learn more about AI because it is one of the technologies that is driving our future.

GROSZ: I teach a course about intelligent systems, design, and ethical challenges. I think that anyone interested in artificial intelligence or design should also be aware of the limitations of the technology and the ethical questions and design challenges that these limitations lead to.

Eric Sun ‘20 is a freshman in Hollis Hall.

By: Priya Amin

Imagine diving into the Gulf of California and reaching a 120 °C hydrothermal vent located deep on the seafloor. Rich in hot hydrogen and carbon dioxide gas, these vents seem to spell death for any creature that dares to swim by. But if you look closely, you’ll notice an organism that not only survives but also thrives in this seemingly toxic environment. How could anything live in such adverse conditions?

HYPERTHERMOPHILES: DON’T SWEAT THE HEAT

Meet Methanopyrus kandleri, Earth’s record-holder for hot temperature growth. Capable of reproducing at 122 °C, M. kandleri is a hyperthermophile, an organism that likes intense heat (1). Hyperthermophiles comprise some of the world’s most extreme life forms and were only discovered a few decades ago in 1965 when Thomas D. Brock isolated them from hot springs at Yellowstone National Park (2). Since then, we’ve been able to learn much more about these resilient organisms.

How have hyperthermophiles adapted to live in such extreme conditions? Normally, under extraordinary heat, a cell membrane disintegrates, allowing toxic chemicals into the cell. However, hyperthermophiles combat this by using high levels of saturated fatty acids to line their membranes (3). This type of structure is quite strong and stable, and it helps the cell stay intact. Another issue is that at such high temperatures, ordinary proteins denature, lose their shape, and cease to function. Hyperthermophiles have evolved to have hyperthermostable proteins that are compact and wound up in spiral-like helixes (4). These proteins can maintain their structure and function even in harsh environments. In fact, they use the high temperature to their advantage: the abundant heat energy makes chemical reactions proceed faster than usual, spurring on the processes that allow cells to proliferate and grow.

To survive, M. kandleri must use unique metabolic pathways tailored to the molecules in its environment. Interestingly, in addition to being a hyperthermophile, M. kandleri is also a methanogen, which means it gets its energy by producing methane in environments where oxygen is absent.5 Its metabolic process looks a little like this: CO2 + 4 H2 → CH4 + 2H2O. M. kandleri is remarkably resourceful. It consumes hydrogen and carbon dioxide, making it a perfect match for deep-sea hydrothermal vents! In addition, the metabolic process is anaerobic, with no need of oxygen! The result is energy in the form of ATP, a special molecule that can be later used to fuel the cell’s basic functions (5). Most hyperthermophiles have similar chemical reactions that use carbon dioxide, iron, or sulfur to anaerobically produce energy. This allows them to live in a vast array of hot environments, like deep-sea vents, hot springs, and terrestrial volcanoes.

M. kandleri’s habitat is characteristic of Earth’s early conditions. Therefore, many scientists claim that the Last Universal Common Ancestor (LUCA), the most recent ancestor of all organisms on Earth, was closely related to M. kandleri (6). Extraordinarily, by studying hyperthermophiles, we’ve been able to open a window into our evolutionary past.

CRYOPHILES: PLAYING IN THE COLD

Now, after taking a dive to visit the scorching hot hydrothermal vents in the Gulf of California, why don’t we cool down a bit? Let’s travel 3800 miles to Ellesmere Island in Antarctica to meet another extreme organism, Planococcus halocryophilus.

If you take a step into the permafrost on Ellesmere Island, you would probably get frostbite pretty quickly. The permafrost contains a lot of salt, which keeps it freezing over even at temperatures as cold as -25 °C. This is the environment in which the cold temperature growth record holder P. halocryophilus lives. At -16 °C it can reproduce, and at -25 °C it is still able to remain active (7). Discovered a century earlier than hyperthermophiles, cryophiles were first described by J. Forster in 1887 upon examining a sample of cold-preserved fish (8).

To adapt to below-freezing temperatures, cryophiles have developed unique structures and molecules. Unlike hyperthermophiles, cryophiles have high levels of polyunsaturated fatty acids, which form malleable and fluid structures that keep their cell membranes from freezing (9). They also have two special types of cold-active proteins: cold shock proteins and antifreeze proteins. Cold shock proteins ‘turn on’ once the temperature falls below a certain threshold. Because they’re designed for flexibility, they are able to help other proteins, such as those needed for DNA replication, function at less ideal temperatures (9). Antifreeze proteins help the cell avoid the harmful effects of thawing and freezing. They release chemicals outside the cell that effectively lower the freezing point of water (5). In this way, cryophiles manipulate the environment around them to survive.

While the exact metabolic pathway for P. halocryophilus is still being researched, it likely derives ATP energy from molecules in its environment in a process similar to that of M. kandleri. Given the low temperatures and thus low amount of energy in the environment, ATP’s role as an energy source becomes even more important than usual. Incredibly, the microbe can still synthesize and break down the molecules it needs at temperatures as low as -25 °C!

This cold temperature organism holds insights about the possibility of similar microbial life on other planets in our solar system. For instance, cryophiles have the ability to live in between ice crystals on Earth; similar environments are found on other celestial bodies, such as on Mars or on Saturn’s moon, Enceladus (10). Scientists are currently racing to discover the secrets these organisms hold about our world and the universe.

EXTREMOPHILES EVERYWHERE

M. kandleri and P. halocryophilus are just two examples of countless extremophiles. Thriving in harsh, adverse environments, extremophiles are like the daredevils of biology—wherever life has an opportunity to develop, extremophiles make a home. This group of organisms consists of life from two broad classifications: Archaea, like M. kandleri, and Bacteria, like P. halocryophilus. Extremophilic creatures from these domains can live in seemingly impossible environments, such as acidic pools, salty lakes, freezing brine water, or extremely hot hydrothermal vents! What makes archaea and bacteria best suited to handle extreme conditions?

The answer is quite simple: they are single-celled organisms. Archaea and Bacteria are the two great branches of life that encompass all prokaryotes. (Eukarya is the third domain, consisting of plants and animals.) When you think of single-celled prokaryotes, which do not have a nucleus, you might only picture a bacterium, like the E. coli that live in your gut. Scientists used to think in the same way, classifying all prokaryotic organisms as bacteria. That is until 1977, when RNA analysis revealed that many single-celled organisms were actually in a separate domain, namely Archaea (11).

But what does being a prokaryote have to do with being more likely to be an extremophile? How does being single-celled allow the possibility for an organism to survive harsh environments? The first reason is that these organisms are able to reproduce much more quickly than complex, multicellular organisms such as plants and animals. They are time and energy efficient. This proves especially advantageous for hyperthermophiles that need to rapidly proliferate across a large surface to capture more nutrients from a deep-sea vent before it collapses. Another reason is that archaea and bacteria do not have a membrane-bounded nucleus, which means that they are able to replicate DNA and create proteins in less time. In cold environments, for example, the cell would be able to efficiently make antifreeze proteins, which are crucial to the survival of cryophiles. It’s also important to note that the ability to quickly reproduce creates opportunities for rapid adaptations to environmental changes.

By studying these amazingly simple yet resourceful organisms, we’ve found the most disparate forms of life. Hyperthermophiles withstand the blistering heat of hydrothermal vents, similar to the environment when life was developing on Earth. Cryophiles survive the freezing cold of Antarctica, similar to environments out in our solar system. We have much to learn from extremophiles both as we seek to understand our evolutionary past and as we look to the future for life beyond Earth.

Priya Amin ’19 is a sophomore in Pforzheimer House concentrating in Integrative Biology.

WORKS CITED

[1] Morris, J. et al. Biology: How Life Works, 2nd ed.; Macmillian Learning: New York, 2016; p 545.

[2] Stetter, K. Extremophiles. 2006, 10, 357-62.

[3] Carablleira, N. J. Bacteriol. 1997, 179, 2766-768. [4] Sterner, R.; Liebl, W. Crit. Rev. Biochem. Mol. Biol. 2001, 36, 39-106.

[5] Methane-Producing Archaea: Methanogens. Boundless Microbiology [Online], May 26, 2016. https:// http://www.boundless.com/microbiology/textbooks/boundless-microbiology-textbook/microbial-evolution-phylogeny-and-diversity-8/ euryarchaeota-111/methane-producing-archaea-methanogens-576-10785/ (accessed Oct. 10, 2016).

[6] Yu, Z. et al. J. Mol. Evol. 2009, 69, 386- 394.

[7] Zimmer, C. Comfortable in the Cold: Life Below Freezing in an Antarctic Lake. NOVA Next [Online], June 11, 2013. http://www.pbs.org/wgbh/ nova/next/nature/seeking-psychrophiles-in-antarctica/ (accessed Oct. 10, 2016).

[8] Ingraham, J. L. J. Bacteriol. 1958, 76, 75-80.

[9] Darling, D. Psychrophile. Encyclopedia of Science: The Worlds of David Darling [Online]. http://www.daviddarling.info/encyclopedia/P/psychrophile.html (accessed Oct. 13, 2016).

[10] Bacterium Planococcus Halocryophilus Offers Clues about Microbial Life on Enceladus, Mars. Science News [Online], May 27, 2013. http://www. sci-news.com/space/article01105-planococcus-halocryophilus-bacterium. html (accessed Oct. 10, 2016).

[11] Archaea. New Mexico Museum of Natural History and Science, http:// treeoflife.nmnaturalhistory.org/archaea.html (accessed Oct. 9, 2016).