The Evolution of Facial Diversity: Why do we Look so Different From One Another?

Have you ever looked at a group of animals of the same species and wondered why they appeared so similar? While humans have distinct features, allowing us to identify specific people, it is difficult for us to tell most members of an animal species apart. Unlike us, their faces usually appear so similar that they can't be distinguished. So why do human faces look so different from each other? 

Facial features among different people vary in length, placement, size, and more

First of all, the main reason we don't all appear the same is because of genetic variation. Through the processes of recombination and independent assortment, the combinations of genes you get from your parents will usually look completely different from that of your siblings. So everybody's genes are unique. That being said, it's important to note that humans aren't nearly as genetically diverse as most other species. If your DNA were compared with another random human's, there would only be around 1 difference per 1,000 base pairs. Animals also use the same processes during meiosis to create genetic variation, yet within the same species they look nearly identical. So if we're so genetically similar to each other, why do we all look so different? There is a new hypothesis:

The evolution of facial uniqueness may have arisen through a type of selection called intersexual selection. This type of selection occurs when an individual of a species has an advantage in finding a mate because their characteristics are more desirable, like a male peacock's colorful feathers attracting females. A more unique facial trait may have been found more attractive, leading to offspring with more distinctive facial features. The reason that other animals didn't evolve the same amount of facial variation as humans is because they don't need to rely on their vision nearly as much as people do. For humans, vision is an incredibly important part of our lives. One study shows that we might perceive up to 80% of our stimuli just from our sight. Meanwhile, animals typically make much more use of their other senses. Some species like dogs and cats evolved to have a particularly strong sense of smell, so they can use that to recognize each other. Birds can recognize each other through their calls. Dolphins can recognize each other through a combination of hearing and taste. When compared with other animals, human senses are generally weaker. So with humans' dependence on their vision, it makes sense that we would evolve in a way that compliments our needs. Humans need to look different from one another because we wouldn't be able to tell each other apart through any sense other than vision.

Bats evolved as nocturnal organisms and typically reside in dark areas. They are able to distinguish each other's voices through echolocation rather than vision, so they don't need to look different from one another.

Genes that code for facial features often have much more variation than genes encoding for other parts of the body. Researchers investigating these genes found that they are much less likely to be linked to each other than genes not encoding for facial features. This means that something like nose shape wouldn't influence eye shape, while, on the other hand, many other traits of the body are encoded by genes that are inherited together. This allows there to be much more diversity in the combination of facial traits that each human acquires. There are also far more genes encoding for facial features than features of any other part of the body. Thousands of genes are actively involved in sculpting your face. The image below shows the results of a study examining how different genes affect different facial features:

More than 130 regions in your DNA encode for you face's traits

This study revealed many interesting findings that show how important facial genes are. Although genes encoding for different parts of the face are usually not linked to each other, they can help influence other parts of the body. Facial features are important indicators of health. Parents can sometimes identify genetic disorders in their children early on because of distinctive facial features. Most interestingly, there appears to be a link between certain facial features and cancer, which implies that some of the genes coding for parts of your face also hold some sway over the likelihood that you will develop this disease. 

Although there are many different options for how facial diversity arose, it is nevertheless an important part of human life that has provided us with many advantages compared to other species. Many animals have to also rely on other senses to identify other members of their species, while us humans are able to recognize each other based on facial features alone. This adaptation is incredibly important to humans, especially recently, with new creations such as facial recognition software, which helps us to identify criminals, missing people, or can just be used for our convenience. Facial diversity allows us to recognize acquaintances and makes each person appear as a completely distinct individual. Whether or not a person likes their appearance, having an exclusive set of features is undeniably an important aspect of each of our unique identities.

Can Capybaras Help Fight Cancer?

Last summer, I vacationed in the amazing city of San Diego. Along with reveling in the beautiful beaches and historical parks, my family made a point to visit the most famous zoo in the US - the San Diego Zoo. With 100 acres of land and hundreds of different species, the San Diego Zoo was certainly an exhilarating place. While most people likely look forward to seeing the majestic lions or cuddly koalas, I was most excited to see the capybaras. 

A capybara with its two capybara pups - how cute!!

I'm sure you've seen capybaras on TikTok, Instagram Reels, or anywhere else you get your fill of social media. From the viral capybara song to videos that make you go "aww" - capybaras are everywhere now - and rightfully so! Capybaras are undeniably adorable animals. Just look at their tiny legs and shaggy fur! As the biggest living rodents on Earth, capybaras can grow to be over 4 ft in length and weigh over 150 pounds, a far cry from other rodents (guinea pigs, mice, hamsters, etc.). Yet despite their size, they truly are gentle giants. They can be found to have birds, monkeys, or their own pups riding on their backs as they walk around or wade through water, as capybaras are excellent swimmers. In Japan, zoos often let them enjoy relaxing in hot springs - tell me that's not absolutely precious. 

Capybaras enjoying a hot spring bath 

In addition to being endearing, capybaras are truly fascinating creatures from a biological standpoint. With capybaras being so drastically different in size compared to their rodent relatives, the question to ask is - how did they evolve? Small size has proved to be an advantage for most rodents as it protects them from predators - especially since most rodents (including capybaras) are herbivores, and carnivorous rodents are equally as unthreatening, sticking to insects and other small organisms. Scientists have hypothesized that capybaras were able to grow in size due to the lack of predators in their habitat when they first developed. The large size of capybaras calls another aspect of their evolution into question - one that might provide insight into treating cancer. 

Cancer is the uncontrolled dividing of cells due to mutations in a cell's DNA, mutations that may develop randomly during DNA replication and cell division. The more cells an animal has, the more DNA replication and cell division occurs, increasing the likelihood of replication errors and mutations. The large size of capybaras mean they have more cells and therefore should indicate an increased risk of cancer, however this is not the case. In fact, there have only been 3 known cases of cancer in capybaras, whilst mice are even more susceptible to cancer than humans are. This absence of a correlation between animal size and cancer risk has confused scientists for years, and is known as Peto's Paradox. A full explanation for this paradox is yet to be found, however, scientists have found that various large animals have developed their own mechanisms for fighting cancer. For example, elephants have twenty copies of the p53 gene, as opposed to most animals having only one. The p53 gene codes for proteins that repair damaged DNA before division or induce apoptosis to prevent cancer development, decreasing the frequency of cancer in elephants. Similarly, bowhead whales are quicker at repairing damage to their DNA than other animals, and are less likely to have errors as well. 

Peto's Paradox demonstrated by comparing the expected vs observed cancer rate

In 2018, scientists found that capybaras had their own cancer-fighting mechanism. The capybara genome was found to have 3 gene families that were larger compared to other rodent genomes. This expansion contributes to the size difference, as well as to a signaling pathway that suppresses cancer cells and is regulated by T-cells. T-cells are a type of white blood cell and an important part of the immune system. T-cells help destroy infected or cancerous cells, and signal for other cells to fight harmful pathogens. This means that capybaras have an immune system that is much better at identifying and terminating cells that divide too fast and have the potential to become cancer. Their innate mechanism is similar to a treatment provided to cancer patients called immunotherapy, in which a patient's immune response is amplified to destroy more cancer cells. Just a few years ago, a groundbreaking form of immunotherapy called CAR T-cell therapy was developed to treat lymphoma and leukemia. This treatment genetically modifies T-cells to synthesize chimeric antigen receptors, allowing the T-cells to find and destroy cancer cells that contain a specific protein. CAR T-cell therapy has proven to be very successful, with 83% of leukemia patients showing complete remission after 3 months, and 50% of lymphoma patients showing signs of remission after 15 to 24 months. With immunotherapy proving to be revolutionary and worthy of further research, capybaras could be a useful thing to study. 

It is with great sorrow and shame that I admit I was unsuccessful in my very important pursuit to see a capybara - though in my defense, the map was very confusing and the zoo is enormous...and I am not big on walking. I was even more disheartened when I visited Turtle Back Zoo the following Fall and found that we do not have capybaras here in Essex County - what a travesty. I have not lost faith, though, and I am even more determined to see one, especially now that I know capybaras are more than just a pretty face. I didn't know it before, and I doubt they know it themselves, but the mere existence of capybaras brings up a whole host of questions as part of the continuously intriguing world of biology.

Ethiopia and Kenya - The Hotbeds of the Marathon World

If you know anything about the marathon world, you've heard the names Eliud Kipchoge, Kenenisa Bekele, Brigid Kosgei, and Yalemzerf Yehualaw. You have probably heard the name Eliud Kipchoge who is most famous for breaking the 2 hour mark for the first time ever in the marathon. There is more than one thing that these people have in common other than being stellar athletes: they are all from either Kenya or Ethiopia. Kenya and Ethiopia are located on the eastern side of the continent of Africa and are known for being running hotbeds of the world. These two countries are home to some of the most rigorous marathon training camps in the world and produce THE BEST distance runners. To put this into perspective, 19 out of the 20 male fastest recorded marathon times EVER were run by people from either Kenya or Ethiopia. Isn't that crazy? Even more insane, 88 out of the fastest 100 recorded marathons were run by men from either Ethiopia or Kenya. In addition to this, 74 out of the 100 fastest marathons run by women EVER were from either Ethiopia or Kenya. The question that emerges is: how is it possible that so many good marathon runners can be from these two countries? Is it genetics? Training? Environment? Culture?

I just want to make it clear that there are many other countries, mostly from Africa and specifically Eastern Africa, that are home to incredible marathon runners. Some of these countries include Eritrea, Uganda, and Tanzania. I chose to focus on Kenya and Ethiopia because they are the two most common origins of ethnicity amongst the elite of the elite Marathon Runners.

Kenya (orange) and Ethiopia (green)

Firstly, I want to focus on the physical features of Kenya and Ethiopia. Both countries are thousands of feet above sea level and have a mountainous environment. Kenya has plateaus reaching an average height of  4,921 feet above sea level while Ethiopia has a high central plateau that varies from 4,232 to 9,843 ft above sea level. The plateaus in both countries are surrounded by mountains that exceed 10,000 feet. The importance of all this is the high elevation. A higher elevation environment entails higher performance training. When you train at higher elevations you develop more endurance. In more detail, it increases oxygen flow to your muscles. There is science behind this! At higher elevations, there is less oxygen in the air and when athletes train at higher elevations, their bodies produce more red blood cells, which allow their blood to carry more oxygen. The hormone that is responsible for increased red blood cell production is erythropoietin (EPO). EPO is secreted by the kidneys in our bodies and this happens when cellular hypoxia occurs. In turn, the release of EPO stimulates red blood cell production in the bone marrow. As red blood cell production is stimulated, and as it increases, it raises your hemoglobin levels. Hemoglobin is a protein in red blood cells that helps blood carry oxygen all throughout the body. This process is a negative feedback loop! EPO is actually used to treat anemia. Bodies naturally build new red blood cells when they are in conditions of low oxygen. This advantage is not significant when they compete at higher elevations and against people from the same area. It is significant when they compete and run marathons at places with lower elevations around the world. The athletes get a natural boost to their muscles when additional oxygen is available (at lower altitudes). 

Erythropoietin Cycle

Runners in Kenya Training

Red Blood Cell

Mount Kenya

Secondly, I want to talk about the physiological aspect that pertains to the bodies of Kenyans and Ethiopians. When you think of someone who is really fast, you may start to picture someone that looks similar to Usain Bolt: 6 feet 5 inches tall, with long legs, and muscular. This body type is not ideal when it comes to distance running. The best distance runners in the world are usually 5 feet 7 inches tall and 130 pounds. For example, Eliud Kipchoge is 5 foot 6 inches tall and 115 pounds. This body type is ideal for distance running because it is the most efficient. In other words, a lower body mass has a clear thermal advantage when running in conditions in which heat-dissipation mechanisms are at their limit. The typical build of a marathon runner from Ethiopia or Kenya is exactly this: small, compact, and highly efficient for long distances.  An average Kenyan’s leg is 400 grams lighter than those of their European competitors, which translates to an energy saving of 8% when running. Over time, communities in Kenya and Ethiopia that produce these world-class runners have evolved and developed superior physical traits better suited for running. 

Eliud Kipchoge

Thirdly, the running culture that surrounds Kenya and Ethiopia is like no other. At young ages, Kenyan and Ethiopian children are running everywhere, especially, school! Many of the nearest schools by villages/communities are miles away. Children have to go to school and based on the circumstances that they live in, they are forced to run to school. Not only does running to school every day serve as a form of training from a young age, but the important detail is also that most of these kids run to school barefoot. Running barefoot increases your foot strength and teaches you to strike the ground softer when you run. And that is a fact! If your feet are strong, then your legs are strong, and then your body is strong. Everything builds from the bottom up so children from Kenya and Ethiopia develop this advantage from a very young age. Do you want to know a fun fact that connects to all of this? Ethiopian Abebe Bikila won the 1960 Olympic marathon running barefoot!

Barefoot Runner

Runners from countries like Ethiopia and Kenya are at the forefront of the marathon world and due to their culture, training, and environment, they have consistently obtained victory. Their historic tradition, physiological evolution, and unprecedented practice have allowed them to sport gold.

Artificial Intelligence and Medicine: The Future is Now.

AI and the Medical Field

Aidan Ouckama

What even is considered AI?

AI, or Artificial Intelligence, is a recent breakthrough in Computer Science. Imagine Intelligence, but artificially made. That wasn't much help. AI is basically a computer that can do what a human can do, think, learn, and complete tasks that require a human-level of intelligence without the support of a human. AI is commonly described as "smart" which it technically true, but this isn't the aspect of AI that we find useful. The presicion an AI has when given data and the pin-point predictions it makes with said given data is what makes AI so useful to us humans.

Artistic representation of Artificial Intelligence

How is AI used in our world?

AI is always helpful when there are large amounts of data involved. And there are massive amounts of data in the medical field: diagnoses, prescriptions, medical documents, etc. Outside of the medical field, however, AI is used in a multitude of areas. The AI that most of you have heard of is probably video game-based AI where your enemies or allies are controlled by computers within the game. These AI give the gaming environment that they are deployed in a more realistic feel, whether it's to simulate a war or even just a peaceful village with passive NPCs (non-player characters) roaming around the terrain.

The most basic form of video game "AI". Pong was the worlds first wide-scale video game to be released and future versions of the game introduced AI.

Here's an example of a Machine Learning AI tic tac toe algorithm that I developed. It learns how to beat you as you play it! (It might take a LOT of games though... I'm still working on it)

If you're interested in looking at the source code take a look at this.

Tic Tac Toe

Other common, everyday examples of AI are Google Home, Alexa, and Siri. This software is known as conversational AI, as in they are used to conversate as if talking to an actual human, versus chatbots which are programmed with already inputted responses. This "conversational" aspect gives the AI a more dynamic feel when speaking to the home assistant, as the responses may differ and change as you tell the AI information about yourself, which the computer takes in as data to be processed in their "brain." This implements an "input to output" system described later.

How is AI used in the Medical Field?

As mentioned above, data such as diagnoses, prescriptions, and medical documents are processed by AI to do a multitude of different tasks. It crunches data and creates predictions based on the given data. An example of this is actually a topic we went over in class. AI was used to predict the protein structures we looked over when learning about the structures of proteins and how their R-groups and amino acids impact the shape. How this is done is the AI is given data about how different R-groups interact with each other and then using that data they can predict the shape of any protein when given an amino acid sequence. It is astonishing to see how many different cases an AI's input-output system can be implemented in!

An example of an AI generated protein structure. Similar to the one presented by Ms. Eckert during one of our lessons.

Another example of AI being used in the medical field, outside of the teachings of class, is the detection of cancerous / dangerous cells based off of stained tissue samples. In a recent study (2018), it was shown that researchers in Google AI Healthcare created an algorithm called LYNA (Lymph Node Assistant) that did the purpose stated above. LYNA took photos of the stained tissue as input and output areas of the photo where cancerous cells are possibly growing. They study found that LYNA was accurate 99% of the time, and also cut the average review time of doctors in half.

Samples that LYNA analyzed. In this sample LYNA found a patch of dangerous cells, bordered in the right panel.

Overall, AI is truly a really interesting subject and you don't have to be some technological genius to understand it. AI is implemented everywhere, even in places you didn't know it existed! I personally have a large facination with AI and have been recently been trying to wrap my mind around the processes it takes to created even a basic AI like the tic-tac-toe algorithm. Relating back to our class, AI was even used in our lesson plan as it was what developed the images we used to look at protein structure. The amount of overlap computer science and biology / medicine in this day and age is astounding, with medical engineering being a possible career path. The possibilities to AI is truly endless.

The Flying Squirrel

Did you know that there are flying squirrels here in New Jersey?  The first time I realized this, I was a little freaked out. I couldn't help but picture a rodent flying at my face. Then, I did some research. Turns out, flying squirrels are quite intriguing and their mechanisms for flight are really cool. Aspects of human inventions like the wingsuit and planes resemble the wings of flying squirrels. How could these creatures have evolved? Do they fly because they are related to birds?

A drawing of a flying squirrel (original photo)

What is a flying squirrel?

This incredibly fascinating creature illustrated above is known as the flying squirrel. It is a mammal and a rodent (not a bird). In the wild, they live on average five to six years. There are about 50 different species of flying squirrels in total. They can be as small as dwarf flying squirrels which are about 3 inches long and weigh about 3.5 ounces. These tiny gliding creatures are found in the Malay Peninsula and frequently get mistaken for large butterflies. They can also be as big as the Japanese giant flying squirrel which is about 2 feet long and weighs about 5 pounds. Flying squirrels can be found worldwide, but are mostly found in Asia. There are 2 species that are native to North America, the northern flying squirrel, and the southern flying squirrel. They are mainly found in forests or woodlands. If these animals are not related to birds, how did they develop the ability to fly?

A flying squirrel gliding to a nearby tree (original photo)

How do they fly?
Okay, so they can’t technically fly, they glide. They developed something called patagia, which produces lift and enables them to glide. A patagium is a special membrane made up of loose skin and underlying muscle that connects the front and back legs. When they spread their limbs apart, the membrane is exposed and the body is transformed into a gliding platform. They can use small leg movements to steer and they can use their tail as a break. They also have a small flap on their wings that curl upwards, similar to the tips of the wings on an airplane. These are theorized to help increase flight efficiency and help control the glide (as it does in commercial planes). A flying squirrel can glide as far as 450 meters (about 1476 feet).

Their ecological niche

Flying squirrels are nocturnal, meaning that they are awake when it is dark outside. For that reason, they can be hard to spot. If you would like to find a flying squirrel, they den in tree cavities and rock crevices. Flying squirrels are omnivores and their diet mostly consists of seeds, fruits, nuts, flower buds, insects, or spiders. Flying squirrels have to be careful of predators including snakes, owls, raccoons, and foxes.

A Flying squirrel on a tree (original image)

Their evolution

Flying squirrels make up the tribe Pteromyini within the squirrel subfamily Sciuridae. They are most closely related to the tree squirrel. Flying squirrels were found to have diverged from tree squirrels during the Oligocene Epoch about 33.9 million to 23 million years ago. Flying squirrels are frequently compared with sugar gliders. They both have big eyes, white bellies, and patagia, and they are both known for their ability to glide from tree to tree. However, flying squirrels are placental mammals and sugar gliders are marsupials. They are not very closely related at all as their most recent common ancestor is most likely a rat-like animal. In actuality, these animals are most likely the result of convergent evolution and their similarities are examples of analogous structures. They live very similar lifestyles. They both jump from trees, necessitating their patagia, and forage for food, leading to large eyes. The environment led to similar selective pressures and they evolved independently from one another.

A sugar glider (original image)

Some examples of adaptations that flying squirrels have developed are a good balance, intricate wrist bones (to help with steering), and fluffy tails to stabilize flight. Their ability to glide makes them very adept at escaping from predators. The adaptations that they have developed over time are part of why flying squirrels are so neat. They are one of a handful of mammals that have developed the ability to glide. Their ability to glide makes them very energy efficient. Since they are mostly active at night and are mostly found high in trees, they are rarely seen or noticed. Both southern and northern flying squirrels can be found in New Jersey, so next time you're walking at night, look up in the trees and see if you notice a flying squirrel.

The Evolution of Teeth: Where Did They Come From and How Have They Changed?

Dentists: the villain in every children's movie, everyone's least favorite doctor to visit and tik-tok's latest obsession. Most consider anyone who devotes their life to looking at and touching other people's teeth strange, but in dentists' defense, teeth are actually fascinating! Did you know that enamel (the shiny coating on your teeth that you can see) is the toughest part of your body? Or that no two people have the same tooth structure? 

Similar to a fingerprint, your "tooth prints" are so specific to you that they are often used in forensic studies to identify bodies! For the same reason, teeth are also valuable tools for evolutionary scientists. They are easy to characterize because they are highly specialized, and the enamel make them sturdy and long-lasting fossils. So, how did these enamel-coated nuggets of history come to be?

Well, teeth emerged shortly after jaw-bearing organisms called gnathostomes emerged from earlier jawless fish. It is unclear whether they evolved jaws for predation, mastication or protection, but whatever the cause, teeth-bearing gnathostomes were more evolutionarily successful than any other organism, which is why teeth are present (in some form) in all vertebrates.

 Image showing the skulls of different vertebrates, including humans

Teeth are variable in number, size and shape across species because of environmental pressures. This includes diet, a major catalyst for modern day human dentition. Our primitive ancestors had a diet that revolved around plants, raw meat, nuts and tree roots. You heard that right, tree roots. Therefore, they needed strong molars and canines to cut through their food. Those with the most teeth and the strongest teeth were able to have the broadest diet, and so they survived and reproduced more often. This is where our wisdom teeth come from.

Image showing wisdom teeth coming in behind molars

Wisdom teeth are essentially back-up teeth, in case early humans wore out all their others. They are now considered vestigial, and most people have to have them removed. Vestigial structures are leftovers from our ancestors that we no longer need, but have not been removed from our gene pool. Wisdom teeth are erratic in growth and often hit against other teeth when they grow in, which is why they cause pain and need to be removed.

Early humans had much larger jaws than we do now, because they needed an immense amount of force to chew. Modern inventions of utensils and cooked food have caused our jaws to shrink, causing a phenomenon known as- you guessed it- “crowded mouth.” This is often corrected with orthodontics or tooth extractions. The opposite is also possible, as some people have hypodontia, which means they are born without several of their adult teeth. This is again because our jaws are shrinking and we do not need as many teeth as our ancestors did. Smaller jaws and cooked food have also resulted in more and more babies born without wisdom teeth, sparing them from the painful removal process and disorienting recovery period.  

Image showing the comparison of an early and modern human skull

Modern teeth are also smaller and closer together, and are coated in a thicker layer of enamel. Our canines have shrunk and dulled dramatically as well, in response to soft, cooked food.

In the future, you can expect to see babies with smaller faces, jaws and teeth, and more and more cases of hypodontia and “crowded mouth.” We have made our environment extremely favorable to us, so we no longer need the large, strong and widely spaced teeth present in early humans. But just because we are evolving to have fewer and smaller teeth doesn’t mean we shouldn’t take care of the ones we’ve got! Make sure to brush and floss twice a day, and see your dentist regularly for cleanings!

What if Tiktaalik had never walked on land?

In this day and age, one certain creature is denied of much of the fame it deserves. 375 million years ago, the concept of humans were foreign on the fiery ball of land we now call Earth. The majority of our world was still covered by ocean, and within these oceans laid countless species of fish and bacteria, without an idea of life outside of the water. That was, until a certain fish stumbled onto land...

Personally, I think he's adorable! (source) 

If you know me well, you know I could discuss the charm of this guy's beady little eyes for hours. But, aside from being so handsome, this crocodile-resembling fish is the reason humans exist today, and it's known as Tiktaalik. Tiktaalik was unique in having a blend of traits from both fish and land animals, becoming the most likely ancestor for the world’s first land vertebrates.

Tiktaalik first emerged from land during the Devonian period. Second in infamy only to the age of dinosaurs, the Devonian period was about 420 to 360 million years ago, often known as the “age of fishes." During this time, sea levels were high and the climate was much warmer and drier than it is today. By the mid-Devonian years, the fossil record shows that new species of fish began to evolve with lobed fins, bones, teeth, and the ability to breath air through spiracles in the skull.

Started out as a fish, how it end up like this? (source)

Why was Tiktaalik able to wander onto land? Tiktaalik, belonging to what would come to be known as the “intermediate” phase of fish and tetrapods, possessed front fins with skeletal structures akin to a crocodile, a mobile neck, and lungs alongside gills. (Tiktaalik) Tiktaalik’s structure provides all the information necessary to understand its lifestyle. Tiktaalik’s front fins differ from the fins of other Devonian fish in that they formed an early basic arm structure, allowing it to raise itself up onto land. Most other fish at the time only had rays of bones in their fins, suited for swimming but not walking. Tiktaalik’s front fins allowed it to migrate to areas inaccessible to its competitors, increasing its chance of survival. Its mobile neck was also advantageous because it allowed Tiktaalik to orient itself in the direction of prey, especially in areas where the body is relatively fixed, like shallow water or land.

Charles Darwin theorized that simple organisms gradually evolved into more complex ones, something that can be supported by analyzing the fossil record. Fossils serve as an important foundation for understanding the history of our planet, and are often more reliable for exploring the relatedness of species than morphological similarities. 

Tiktaalik's fossil (source)

Tiktaalik’s structure is the ideal model of an intermediate evolutionary phase between fish and tetrapods. Tiktaalik’s fossil was first discovered by Neil Shubin (Your Inner Fish) and a team of paleontologists in ancient stream beds in the Nunavut Territory of the Arctic. Shubin had embarked on his journey to the Arctic in search of the missing link between sea and land animals, and Tiktaalik provided the perfect blueprint for his research. Before the unearthing of Tiktaalik, scientists had long theorized about a fossil that could fill the gaps in their knowledge, but had no such fossil to present to the evolutionary nonbelievers.

Despite the overwhelming amount of evidence supporting the theory of evolution, plenty of people still refuse to accept it as fact. Looking back in America's history, in 1925 the Scopes Monkey Trial brought up the debate of the legitimacy of Darwin's ideas. John Thomas Scopes was accused of teaching evolution in schools, which at the time was ruled to be a violation of Tennessee state law. With this trial taking place in the early nineteenth century, Tiktaalik's big break in science was yet to come, and Scopes was fined for his violation. Yet, this was far from the end.

Since Shubin’s discovery in 2004, things have started to change. Tiktaalik has been used to defend the education of evolution in schools, like during the Kitzmiller v. Dover trial in 2005. In this trial, arguers for the concept of “intelligent design,” later revealed to be a veiled concept of creationism, asserted that some organisms were simply too complex to have evolved through Darwin’s theory of evolution. The discovery and presentation of Tiktaalik during this trial was monumental in turning the decision and proving to the intelligent design team the validity of Darwin’s logic.

Remember your roots! (source)

But, why does it matter that we know where we came from, anyways? This is because knowing our history allows us to bridge a deeper connection between ourselves and the planet we inhabit, as well as the other species we share it with. Humans have a tendency of thinking about the world in terms of themselves, but evolution supports that, even if humans are the dominant species in current day, mass extinctions like the Cretaceous-Tertiary extinction are always possible--and, with the rate the Earth is warming today, many scientists even theorize we are on the brink of another mass extinction, one humans may or not live to tell the tale of.

Evolutionary biology allows us to understand the principles behind the origins and extinction of diverse species. Our Earth continues to change whether its species are aware of it or not, and if we don't keep evolving to suit these changes, we risk facing a similar end to our friends the dinosaurs.

Now for the final question: what would we REALLY be doing without Tiktaalik?

Most likely, eating plants and small fish. Definitely not writing blog posts. So, the next time you want to complain about something, don't blame life; blame Tiktaalik. Tiktaalik is the reason we have to go to school every day, and Tiktaalik is the indirect cause of millions of horrible conflicts, worldwide poverty, hunger, inequality, you name it! Do you think Devonian fish had complex enough thought to establish capitalism? Well, I guess we'll never know. At the same time, without Tiktaalik, there would be no such thing as AP Biology, so feel free to weigh the pros and cons ;) 

So, just remember-- you owe your life to this little fish! And trust me, it gets cuter the longer you look at it.

The Science of Siblings

As an only child, I have always been fascinated by siblings. Just like an exclusive club, the complex interactions between my friends and their siblings seemed foreign and complicated to me. Simple things, like the way they argued, or shopped for each other, or complained together, made me yearn for that level of easy companionship.

My dad (left) and his four siblings. Even through this image, you begin to get a sense of their differences.

When I was in ninth grade, I became good friends with a girl who was the third child in her family. She lived far away, so I would spend weeks at time staying with her family. And although I really did love her, I had an ulterior motive! Each night, I would excitedly call my parents, recalling stories about fights between the assertive and intelligent eldest brother, tactful and anxious middle sister, and my creative and confident friend. And as I was being drawn into the family fray, I quickly became engrossed with the effect sibling order had on their very different characters. Could the differences between my friend's siblings be explained by adaptive radiation? Was it possible that, like the anoles we had learned about in AP biology, it was the need to crush competition that drove siblings to occupy different roles, or niches, in the family?

The family who fueled my interest in siblings!

 

Looking for answers, I turned to the psychologist Frank J. Sulloway. It was Sulloway who popularized the Family Niche Theory in the1990s, arguing that it was a sibling's need to eliminate competition for parental attention that shaped personality. According to him, there are distinctive factors in every family that cause similar traits to develop in most people born in the same family position.

Take the first born, for example. During the first few years of development, eldest children have zero competition for their parents' time and attention. Score! The lack of sibling rivalry means that the only pressure exerted on their personality comes from their parents. This results in eldest children who are high achievers and respectful of authority, as these are traits that most parents esteem. The excess of attention also results in slightly higher IQs, and an over representation of first borns at both Harvard and Yale. In fact, eldest children make up 41% of Harvard's class of 2021! 

Moreover, once competition is introduced into the family in the form of siblings, first borns have a clear physical advantage from the get-go. This makes them more likely to use physical power then their younger siblings, who have to resort to social manipulation. (Side note!!! Some famous firsts include Hillary Clinton, Beyoncé, Winston Churchill, and all the actors who played James Bond. Fits the mold if you ask me!)

James Bond: the self assured prototype of the eldest child. (source)

Next up, and the most interesting in my mind, is the middle sibling. In the animal kingdom, parents are more likely to favor first borns, who are closer to their reproductive years, and last borns, who are more susceptible to disease and predation. Although this trend is much less distinct in the human world, the stereotype of the forgotten middle child certainly rings true. According to Sulloway's theory, middle children are more self-sufficient than their siblings, and generally removed from the family group. They're also usually lower academic achievers than their older and younger siblings. In that same Harvard class that was 41% oldest child, only 14.5% were middle children compared to about 20% of the general population.

Although a joke, the popularity of shirts like this one demonstrates just how deeply sibling stereotypes resonate. (source)

Finally, comes the youngest child. Stereotyped as the baby from birth, last borns come into families that have a more limited number of available niches. As a result, youngest children turn towards experimentation that allows them to find their own unique, uninhabited place in the family group. This often creates a youngest child who is more comfortable with risk and unpredictability than their older siblings. An interesting youngest child fact: it was youngest children that were the first financial backers of the Enlightenment. How's that for an exploratory spirit?

Famous siblings I have always been fascinated by! (source)

Although I found Sulloway's theory fascinating, I was skeptical about its ability to be proven empirically. However, after some research, I was pleasantly surprised that I was able to put my skepticism to rest. First borns, for example, are statistically less likely to participate in dangerous sports than their siblings. They are also much more likely to report self-assuredness at work and demonstrate a higher ego than their younger counterparts. Both of these statistics are consistent with the description of oldest children as responsible and high achieving. 

And, although the following is purely anecdotal, I was also interested to note that dictators like Stalin and Mussolini were eldest children, while groundbreaking thinkers like Marx and Darwin were youngest children. 

In fact, it was Darwin who is responsible for much of our modern day understanding of evolution and ecology. The Family Niche Theory itself would not have been possible without his observation of finches. While on the Galapagos, Darwin realized that the fourteen distinct species of finches he was watching had all evolved from a shared common ancestor. In order to decrease competition for resources, the populations of finches had evolved over time to fill different ecological niches within the environment. This process, called adaptive radiation, increased the fitness of all the newly speciated birds. 

Adaptive radiation as observed by Charles Darwin. (source)

Much like Darwin's finches, siblings are able to survive and thrive when they have the least possible competition for their parents' time and energy. This leads children to go to great lengths (subconsciously of course) to differentiate themselves. Think of it like this: if you and your brother both play guitar, you only have access to half of your parents nurturing love and attention at the end of year concert. But, if you take up painting while your brother plays guitar, you won't have any competition for their time at the art show. 

Although this is a simplistic example, it is effective in proving the point at hand. By separating themselves from their siblings, children are finding unoccupied niches, and performing their own form of adaptive radiation, within the family unit. 

Now, it is important to know that the data supporting this Family Niche Theory is limited at best. Every family is different, which makes it nearly impossible to observe consistent trends between a large sample of family groups. Additionally, most of the statistical data about personality is self-reported, making it both biased and precise. However, the ecological premise of natural selection influencing family structure is a strong one. So next time you get into a fight with your siblings, take a moment to think about why. Perhaps it's because you've been competing for the same ecological niche!