Human Variation: High Altitude

            High altitude affects many people, past and present, around the world. Often, high altitudes have dangerous effects on people who are not used to it. It may cause hypoxia in many people due to the lack of oxygen that is being supplied to the lungs (There is not less oxygen at higher altitudes, it is just less concentrated). This is because as the altitude increases, air pressure decreases making it harder for oxygen to permeate the lung membrane. Among others, consequences include difficulty breathing, headaches, vomiting, and fatigue. Fortunately, our bodies have been perfecting ways to deal with the stress of changing altitudes.

            Short-term adaptions to hypoxia and other altitude sicknesses are vomiting, fatigue, and headaches. As our bodies are receiving less oxygen, they do their best to compensate and, in turn, indulge minor pains (like the headaches) rather than something more severe like death. This is considered a short-term adaption because the symptoms of altitude sickness disappear once the person suffering returns to his or her normal environment.

            A developmental adaption to high altitude is the increased production of hemoglobin in the blood. The high level of hemoglobin in blood permits higher levels of oxygen to be transported to the lungs, in addition to increasing lung expansion. After hundreds of generations of dealing with the lack of oxygen, Tibetans have perfected this development from birth, resulting in rosy cheeks. People who have lived at high altitudes for many generations will certainly have redder cheeks from birth than those who have only lived there for a short time.

            A facultative response to high altitude is heightened fitness. Many athletes training for the Olympics are often coached at much higher altitudes than their normal environments, because they believe it will result in a “short-term developmental” adaption. As discussed above, with lower oxygen levels and air pressure cause hemoglobin production to increase. This process allows athletes to gain a normal fitness standard while at higher altitudes, and consequently enhanced fitness at lower altitudes. However, their bodies have not been structured to continue doing this like Tibetans and their enhanced fitness soon fades back to normal.

            A cultural adaptation to high altitude is the practice of yoga and meditation by Nepalese Buddhist monks. The deep breathing helps transport oxygen to the lungs at a normal rate. Studies by the High Altitude Medical Research Centre have concluded that yoga and deep breathing can reduce the effects of hypoxia in those who practice it regularly.

            Studying human variation from this perspective allows us to understand how our bodies adapt and function under different conditions. Scientists can see how bodies adapt to the different environments and further understand what the environments may have been like in the past. These studies also indicate that race would have no explanation for the genetic changes seen across environmental clines. The changes that have occurred genotypically and phenotypically are results of people living in an area for a long period of time, regardless of who they were "racially." Race is a poor way to study adaptations, because there are so many similarities between racial groups. Race itself is made up in order to describe people who look different from one another, although there is more genetic variation within a single racial group than between multiple. Environmental stresses are the best way to understand the causes for skin color and many other genetic variations seen around the world.

Piltdown Man

            One of the most famous scientific hoaxes in the past century is known as the Piltdown Man. Surprisingly, not many know who or what this is. Piltdown Man is a set of fossilized ‘hominoid’ cranial remains discovered by Charles Dawson in 1912 in Sussex, England. At the time, many scientists, including Arthur Smith Woodward (a renowned geologist at London’s Natural History Museum) who worked with Dawson studying the remains, believed that these fossils were the key to the connection between human and ape evolution. It is important to note that at this time many believed that man directly evolved from apes, which we now know is not true. Rather, they are more like cousins, evolving from a common ancestor and following two separate paths. From the remains, Dawson and others interpreted that the brain and skull evolved to be more human-like than ape-like before upright walking, which we also now know is the exact opposite of what happened. The scientific community exalted Dawson and Woodward, and proudly agreed with the two. Any doubts were either dismissed because of Woodward’s status or kept quiet because of the popular opinion. The hoax was not discovered until almost half a century later when other fossils being unearthed in other continents like Asia had no resemblance to the Piltdown Man. In 1949, Dr. Kenneth Oakley, a geologist at the Natural History Museum, used fluorine testing to date the remains. Fluorine from the soil is absorbed into bones as they fossilize so, the older the bones, the higher the fluorine content. He discovered that they were much younger than the million years old that Dawson had originally suggested. When newer and better dating techniques were created, scientists found that the remains were no more than 100 years old and belonged to a female orangutan. Most scientists were baffled, betrayed, and disappointed with the fraud. It was then that they realized that science was something that people could fake if they wanted to; it wasn’t as honorable as they thought. The Piltdown Man steered human evolution studies in the wrong direction for years, preventing many from studying other important and true finds.

            Fortunately and unfortunately, scientists are human and have their faults. Whomever was behind this hoax, whether it be Dawson or other insignificant aids, they let their jealousy, hubris, and need for attention get in the way of science. Many have noted that the reasoning for doing this might have been to gain fame for himself and/or his country. At the time, there had been no hominoid remains found in England, so it is possible that this may have pushed someone to create this elaborate hoax. With everyone being so excited about the remains, many forgot the scientific process. When finding remains that could be potentially theory altering, scientists are supposed to question and test the hypothesis to the best of their abilities. In this scenario, it seems that with all of the excitement and pride for their country, there was no questioning whether or not the remains were real. As we have learned from the ancient Greeks, hubris may result in tragic consequences and this was one of those tragedies. Fortunately for modern scientists, scientists in the mid-twentieth century remembered what it meant to be a scientist. After doubt concerning the authenticity of the skull was made public, scientists began using new dating technologies to test the legitimacy of the fossils. First, scientists tested the fluorine content in the fossils, which concluded that these were too young to be from before Homo sapiens’ introduction to the world (the content was much to low for something that was supposed to be millions of years old). Then in 1953, scientists used more advance dating methods such as nitrogen and carbon level testing to completely analyze the fossils. From these tests, scientists discovered that the fossils were no more than 100 years old and had been stained artificially with iron. This hoax is an example of how important it is to continually test and re-test fossils until the evidence can be falsified or proven true. Removing the ‘human’ factor from science may reduce errors like this from happening again in the long run, but it could also halt the furtherance of scientific knowledge. I don’t see a way of removing the ‘human’ factor from science, but it could be disastrous if it were so. Without the ‘human’ factor, there wouldn’t be the curiosity involved in science that pushes people to pursue new and wild ideas, which so often result in the discovery of something new. Curiosity is the key to science, and if everyone thought like robots, who knows what would become of our future knowledge. There is much to learn from this unfortunate hoax, but most importantly, it is essential to remember that one must not always rely on one source of information, especially in the scientific community. Checking the facts and sources of new information is key to making sure that the truth is being told. Scientists ignored the part of the scientific method that recommends multiple tests be done to check credibility of unverified sources, and in the end it wound up being one of the biggest regrets in the scientific community.

Homologous and Analogous Traits

Homologous Traits

The homologous trait I decided to research is the tail of the cheetah and the snow leopard. The cheetah, also known as Acinonyx jubatus, lives predominantly in eastern and southern Africa. Cheetahs are large, spotted, and slender cats that are known for their speed. They have small rounded heads with short ears, and distinctive black tear marks under their eyes. Snow leopards, otherwise known as Panthera uncia, are found in parts of Asia, and are very similar to cheetahs. Snow leopards are generally shorter than cheetahs and have their own distinctive spots. They have long thick fur, short fore limbs, and long hind limbs.

Cheetah tails are usually 60-80 centimeters long and are exceptionally muscular. They are used for balance and steering when running. The rudder-like tail allows cheetahs to make sharp turns at high speeds. Snow Leopards' tails are longer than a cheetah's (~80-100 cm) and make up most of their total body length. The tail is fatty and is covered with long thick fur. This comes in handy because snow leopards use their tails as scarves when sleeping. Similar to the cheetah, the snow leopard also uses their tails for balance when walking along rocky terrain. Generally, the tails' of the two cats' structure are very similar, with the most differences being muscles and fur. The major differences seen in the tails are attributed to the different environments and needs: cheetahs for running and snow leopards for warmth.

In addition to other species with a similar trait, the cheetah and snow leopard are both mammals, which suggests that the common ancestor for this case is a prehistoric mammal. Knowing that there are other mammals that have functioning tails like these two cats, suggests that the common ancestor also had a functioning tail.

Cheetah

Snow Leopard

Analogous Traits 

Two species that have the analogous webbed feet trait are the American green tree frog (Hyla cinerea) and the duck-billed platypus (Ornithorhynchus anatinus). Tree frogs are found in central and southeastern United States, and vary in shades of green often with white or cream spots on their backs. They prefer to live in areas that have many floating vegetation or cattails in marshy or lake areas. Platypuses are eastern Australian mammals that live on land and hunt underwater. They have thick, waterproof fur covering their streamlined bodies, not found on their webbed feet and bill.

Although these two species are very different from one another, both have skin flaps that connect toes together (webbing). The tree frog's forefeet have large toe pads with minimal webbing at the base of their toes, while their hind feet have extensive webbing. The webbing for tree (and other) frogs allows them to swim faster and leap higher. The minimal webbing on the forefeet is made up for with sticky pads, so that they can sit and hang on vegetation and trees. Platypuses have larger webbed front feet that also helps propel them when swimming. The difference in webbed front and hind feet between these two species is because frogs use their hind legs for swimming (front webbed feet would not be as useful) and the platypus mainly uses their front feet for swimming. When on land, webbing retracts as claws protrude. This is to make it easier for them to walk and dig burrows for living in.

I do not believe a common ancestor shared this trait. In my opinion, webbed feet came about through evolution in order to make swimming easier and more efficient for different environments. Many animals have this trait, but it is clear that there are minute differences between each animal possessing it.

Platypus

Tree Frog

Protein Synthesis

CATATACTTGTAAGTCTGAAGTGGCACCCTGTCATCCATCGGTA

Historical Influences on Darwin

In my opinion, Thomas Malthus had the greatest influence of Darwin's work on natural selection. Malthus studied and developed ideas about human population, which Darwin later extended to his study of biology. In "Essay on the Principle of Population," Malthus discussed limiting human population growth. Offspring were being produced more rapidly than the resources that were essential to survival were. He pointed out that this often resulted in death, poverty, and famine among other unfortunate consequences. Malthus believed that these were natural outcomes, but were still caused by a divine source. (http://www.ucmp.berkeley.edu/history/malthus.html)

Inspired by Malthus’s studies, Darwin concluded that there is a constant competition for resources between all living beings (animals, plants, man), and those who could find more resources would have a higher chance of survival and reproduction. Further consideration of how different organisms were more equipped to survive than others resulted in Darwin proposing natural selection. “Resources are limited” was strongly inspired by Malthus. He stated that as population increased, resource production remained mostly constant, which in turn limited the number of offspring that would survive. Thus solidifying Darwin’s claim that “there will not be enough resources available for all organisms to reproduce as many offspring as they can.” From there, Darwin considered who would be more likely to survive and how the competition for resources affected organisms, which gave way to his understanding that “organisms with better access to resources will be more successful in their reproductive efforts.”

I think Thomas Malthus's information was essential to Charles Darwin's development of his theory of evolution. The ideas of reproduction rates and competition of resources is what allowed Darwin to consolidate the concept of natural selection. I don't know if Darwin would have been able to develop this theory without Malthus. Darwin built upon the knowledge of Malthus and many other scientists during his time spent studying evolution, which is what science is all about. He may have been able to develop these ideas without Malthus and other scientists, but it would have taken Darwin a considerably longer amount of time to do so.

The church's attitude towards natural selection and other evolutionary notions was extremely negative, and greatly affected Darwin's decision to publish his findings. Originally he did not want to publish because of his fear of backlash from the church, society, and even his own wife. Fortunately enough for the current world population, Darwin published his works when he heard that another scientist (Alfred Russel Wallace) was going to publish a paper on his concept of natural selection. Darwin didn't want someone else taking credit for this concept, so he published a paper presenting his work. His work did not receive much attention until he published the infamous On the Origin of Species.

The Thing about Desert Islands...

"Choose two items you would take to a desert island if you were stranded there."

The thing about desert islands is that there are so many variables: fauna, flora, size of the island, etc. For this scenario, I imagine being stranded on an island that is slightly smaller than the island of Manhattan, so I have areas to explore. I'm surrounded by palm trees and other fruit-bearing plants and soft white sands. Basically, my deserted island is pretty sweet, besides for being deserted. I would bring a survival key chain I have, consisting of a small piece of rope and a piece of flint. To me, fire is the most essential to my survival. With fire, I can cook food (assuming that I can find meat), boil water to make it drinkable, and have campfires to keep myself warm if need be. The keychain is an obvious choice for me, but my second item is not so easy to choose. I would probably bring a book or a book series. I want something that will help me from going insane from solitude. I would love to bring multiple books, so I don't finish one and have to re-read it over and over again, but I feel like that is cheating. I think an educational book would be good, but it would need to be something interesting to me as well. I think Carl Sagan is my best bet for something interesting, educational, and most importantly, understandable. I have yet to read Cosmos, so maybe that would be my first choice. If I had a single book that contained his entire literary collection, that would be ideal. And that's it. Those are the "two" items that I would bring to a deserted island: something for my survival and something my for sanity.