Human Variation and Race Blog

The amount of exposure to high levels of solar radiation can be detrimental to the homeostasis condition of human physiology in many ways including uncomfortable burning of the skin, destruction of folic acid or folate, and the increase risk of skin cancer.  People who are at higher risk of these issues are people who have lighter skin pigmentation. This is because they, through evolution, produce a defective form of skin protein called melancortin- 1 receptor. This defective gene causes their pigmentation to be lighter allowing for less protection from ultra violet rays. While this is beneficial for the absorption of the necessary amounts of vitamin D, these people do not benefit from the same protections against the harmful aspects of high levels of solar radiation. The destruction of folate can cause anemia. The destruction of folic acid can cause birth deficiencies in pregnant women because folic acid is essential to the reproduction of DNA. With less protection from the ability to produce melanin people with lighter pigmentation are at greater risk of skin cancer like melanoma. Burning of the skin, increased risk of birth deficiencies and diseases such as cancer and anemia all can result in upsetting the homeostasis of human physiology making it hard for certain types of skin pigmented people to survive in environments that they were not evolutionarily adapted to. On the other hand, people who have darker pigmentation to adapt to living in places with high levels of solar radiation developed the ability to produce melanin in order to protect from the destructive properties of ultra violet rays. As darker pigmented people thrive in areas with a lot of UVB, these people suffer from the inability to produce vitamin D in areas that do not receive the high levels of solar radiation. This too can affect the homeostasis of the human physiology in that these people will develop weak bones due to the lack of vitamin D produced in their bodies.

Humans have adapted to dealing with high levels of solar radiation through four different methods: short-term, facultative, developmental, and cultural. Short-term adaptations for higher levels of solar radiation in the body’s physiology are hard to pin-point. Perhaps there really is not any short-term mechanism to defend the skin from high levels of solar radiation unless that population’s skin pigmentation already has large amounts of melanin. Other strategies for short-term adaptation may be something like seeking shelter or shade or simply covering the skin in an effort to protect it from solar radiation.

Shelter to protect from sun

Original origins had high levels of melanin

An example of facultative adaptation to higher levels of solar radiation in light pigmented people would be the increased amount of melanin in that population’s skin. The increase of melanin is considered a seasonal acclimatization in that melanin is increased in the summer and decreased in the winter. Melanin is the body’s natural defense against radiation from the sun. It gathers under the skins surfaces to act as a natural sunscreen against the harmful rays of ultra violet light. Specialized cells called melanocytes produces the melanin in response to radiation which can cause a change in the skins pigment generally a few hours after exposure. The increase in melanin is seen by a change in the skins pigmentation, tanning. Tanning is a facultative adaptive trait to help the body’s physiology to remain in a homeostasis state.

Skins reaction to seasonal climate change

Increase in melanin changing skin pigmentation

The next example of protection from solar radiation is through developmental adaptations. Develop adaptations to high levels of solar radiation is what produces the difference in skin pigmentation which constitutes the idea of race. The developmental trait of skin pigmentation to allow a certain degree of UVB to either penetrate or not penetrate a person’s skin   is an evolutionary trait that has been developed over a long period of time through natural selection to allow that person optimal survival ability in the environment in which they live. These traits are inherited through birth and are developed over generations. Evidence of this trend is seen in populations and where they live in respect to the equator. The populations who live closer to the equator experience a higher level of solar radiation. In response to this higher level of UVB, these populations develop darker pigmented skin through the level of melanin in their skin. The melanin acts as a natural sunscreen protecting these populations from skin cancer and the destruction of folate and folic acid in their bodies. People who live closer to the poles and experience less solar radiation over time developed lighter skin pigmentation in order for their bodies to receive more of the solar radiation in an effort to produce vitamin D. Since these populations live in an area that receives less radiation from the sun it is essential to optimize the absorption of the suns radiation in order to maintain a balance of vitamin D in their systems.

Human variation of skin pigmenation

Human variation of skin pigmentation in relation to where populations live

Lastly, cultural adaptations have been made to accommodate the different needs of different pigmented people. Dark skinned people have since moved away from the equator and light skin people have since moved closer to the equator which creates a awareness of how to culturally adapt to the new environments in which their skin pigmentation is not adapted for. Dark pigmented people adapt culturally to areas with less solar radiation in that they must find other ways to receive the necessary amounts of vitamin D. Since the Inuit people are relatively dark pigmented for living in a place with low solar radiation they had to find a way to ensure they were receiving the amount of vitamin D they needed. The Inuit people have adapted to their vitamin deficiency by eating a diet that consist of fish and large mammal blubber. Another cultural adaptation to the lack in vitamin D could be the production of synthesized vitamin D that people can take in a supplemental form. Light pigmented people who have moved to areas with higher levels of solar radiation have adapted culturally through the use of sunscreen and protective clothing in order to shield their skin from harmful radiation. Clothing such as breathable material, bathing suits, and large hats can all be seen as a cultural response to shield radiation.

Sunscreen

Protective clothing

Supplements

Large mammal diet

There are many benefits to studying human variation in their ability to tolerate solar radiation across environmental clines because the better understanding we have of our genetic make-up in response to environmental stressor the better we are to ensure maximum survival. The exploration of skin pigmentation in relation to solar radiation is very important to understand and appreciate. As a light pigmented individual it was interesting to see how genetically my ancestry evolved to allow the absorption of solar radiation in order for my ancestors to maintain the necessary levels of vitamin D needed to function.  The ability for my skin to tan is a fascinating way to see that my pigmentation can adapt facultative to help shield the destructive properties of solar radiation. Furthermore, for me and other light skinned individuals it is important to understand the damaging effects of solar radiation and know how to protect the skin from it. Conversely, it is equally important, and not so prevalent that darker pigmented people living in places with less solar radiation really need to be made more aware of the need for vitamin D in their bodies. Most people are aware of the damaging effect of too much solar radiation, but many are unaware of the damaging effect of too little solar radiation in darker pigmented people. This is an important aspect of the studying of human variation and environmental clines to ensure that light and dark pigmented people are aware of how to maximize their health in an environment they may have not been adapted to through evolution.

The reason why I picked this trait to explore is because it is the most prevalent signifier of race. Why is it that people from Africa are darker pigmented that the Norwegians? Why does the color of a person’s skin determine that person’s worth? Who claimed white skinned people to be superior to all other skin types? What does skin pigmentation have to do with politics, intellect, ability, social status, or wealth, when really skin pigmentation is an evolutionary result of a population’s ability to survive in the environment in which they inhabit? If race really had any significance to a difference in a person genetic make-up then why are all humans 99.9% the same? The only way race could explain the human variation in skin pigmentation is if race was another way of saying evolutionary changes in the level of melanin to maximize exposure or protection from solar radiation in respects to the need of a population in their relation to the equator. The study of evolution to environmental stresses is a way better way to study human variation rather than race because it allows us to see why populations from Africa have darker pigmentation. It allows people to understand that people with darker pigmentation developed that trait in order to withstand the environmental stressors in their area. The reason why Norwegians developed lighter pigmentation is so they could ensure they were able to produce vitamin D from the lower amounts of solar radiation in their environment. When human variation is studied through evolution, it is fascinating to see how evolution works through natural selection in order to increase a higher rate of survival. When looking at human variation through evolution, race is no longer relevant. Without race, racial discrimination is no longer relevant. Instead, people can understand the genetic make-up of a human body and its ability to endure environmental stressors, focusing their attention on biology rather than the physical differences which create false misconceptions of a person’s ability based on the color of his/her skin.  

Language Post

For the first part of the language assignment I had a 15 minute communication session without the use of language, sing, or writing. I completed this exercise with my boyfriend. At first I found this exercise to be difficult only in that it was hard to keep myself from innately responding with words to his discussion. I think that I, and others, am so used to being able to communicate without boundaries so it was strange to not just say what was on my mind. I ended up lasting the whole 15 minutes for this part.

In the beginning of the exercise my partner just talked normal, telling me about work and his day. I sat and nodded, showing that I was listening. It was not until the conversation required feedback from me that it was weird. Being able to use body language was nice in the first part of the conversation and did not hinder our ability to communicate, as far as one person speaking and the other listening. When I tried to communicate my ideas about his day or advice about work is when it was challenging. I tried to using head nod and hand motions, not signals, to communicate but this did not work that well. After that failed I tried grunting the noise of what I thought the words should sound like, but I think that may have made it worse because now my partner had to try to decipher what I was grunting. He changed in small ways about how he talked, but I think because he knew what the exercise was he just laughed a lot.

If we were two different cultures meeting for the first time I think that the culture that speaks a language would have the upper hand in communicating complex ideas only because there are larger ideas than those that can be made through body language. Through spoken language governments are made, scientist communicate, mathematics takes place, faith is build, cities are build and destroyed, etc. Through body language one is able to communicate feelings, emotions, intentions, but complex ideas are not translated through body language alone. I think the culture who speaks thinks of themselves as superior and does not bother to learn how to communicate with those who cannot speak. As being the person, who can readily communicate with most of society, it is hard for us to take into consideration those who cannot communicate as easily. It is for this reason that people who speak the dominate language really do not try to even understand or communicate with someone who doesn’t. It is almost assumed that that person should know how to communicate with you, or you will not even try to communicate with them. I think that a culture who endures this daily is deaf/mute people. I remember I had a deaf girl in my communication class. While it was hard to talk to her, she had a great personality and used her body language to make jokes, address the class, and express her gratitude. She did not have any problem conveying her feelings or emotions with the class, but if we wanted to talk to her about complex issues we would need to translate through her interpreter. I think sometimes when speaking with deaf people you may try speaking louder or slower in hopes they might hear you (which we know would not happen, it’s just habit) or in hopes that they can read your lips. Also you could just write your message to the person because they can read and know the written language.

For the second part of this exercise I had a verbal conversation without any body language, hand signals, changes in tone or pitch, or facial expressions. This part of the exercise was far more challenging for me and I was not able to last the whole 15 minutes before I started talking with my hands. That was the hardest part was not being able to use my hands in a conversation. At first it was fine because I was just very monotone, which was weird because nobody really talks that way. After about 7 minutes I ended up using my hands as an innate reaction to conversation. This was where I had the most challenge and failed the test.

For this experiment my partner did not know really how to read me. Of course he had the ability to understand the words that I was using and their denotation, but it was hard for him to interpret the connotation of the word through my lack of emotion and body language. It really made for a very dull and boring conversation. Had this not been an experiment I think my partner would have thought I was depressed or mad or something.

I think that this experiment really speaks to the necessity of body language in order to communicate more than just words. Spoken language is great to tackle communication of complex issues, but if you cannot express yourself through any of the said motions of body language than it really hinders the other person’s ability to comprehend your feelings about an issue, argument, or conversation. Without the use of body language it is hard for the respondent to fully understand what your message means with a flawed delivery. It is hard to know what it behind words sometimes because the emotions are not there to fill in the blanks.

There is a disease called Pragmatic language impairment which hinders people’s ability to read, understand, and comprehend body language. This impairment is associated with people who suffer from autism, Asperger syndrome, ADHD, and mental retardation. The adaptive benefit to being able to read body language is a great benefit to humans because it allows us to be able to read peoples intentions. As said before body language allows us to fill in the blanks, the things that words cannot express, but body language can. Living without the ability to read people’s emotions could be hindering and detrimental especially for those who suffer from the previously listed illnesses. Honestly I do not think I can come up with an environment that would benefit from the inability to read body language. Body language is so important. It does not generally lie, it can tell us things about someone, it can be beneficial when you have young children, and it lets you know of a person’s intentions, either honest or dishonest. In my opinion there really is not a benefit to lacking this ability to intuitively read a person based on their physical reactions.

Piltdown Man Hoax

Piltdown Man Fossils

The Piltdown hoax was a fraudulent attempt to find a Paleolithic ancestor in England in 1912. Neighboring countries such as France, Germany, and Asia having already found primitive fossils may have been the motive for the culprit(s) to conjure up such an elaborate and dishonest scheme. Amateur archeologist Charles Dawson claimed to have found a piece of a human skull in a pile of rock pebbles. After calling in two colleges, Author Smith Woodward, who worked for the natural history museum, and French paleontologist Father Pierre Teilhard de Chardin, the three man found more remains of what looked to be a Paleolithic ancestor right there in Piltdown, England. To add to the intricate hoax, animal remains were also found among the fragmented skull pieces so scientists were able to date the bones to around a million years old. The most important aspect of the Piltdown hoax is that the evidence found seemed to provide the missing link between human and ape relations and evolution. Dawson himself is credited with finding the most shocking bone of them all, a jaw bone which seemed ape like, yet had a pair of human like teeth. The scientific community celebrated the news that finally England had fossils from ancient ancestors; furthermore, that those remains were the missing link in evolution, finally tying humans to their primate cousins and the oldest discovery of all ancestral fossils. Woodward’s credibility as a scientist added a level of confidence in the findings. In addition to the mentioned motive for the Piltdown hoax, Author Keith, England’s leading anatomist, theorized that larger brains developed before bipedal locomotives in humans; the remains found at Piltdown supported Keith’s theory of evolution, making him one of the largest supporters of Piltdown man. The dig site for Piltdown mans remain continued to offer more evidence, silencing skeptics to any fallacies in the findings. However, ironically after the death of Dawson, no more Piltdown remains were found at the site, or anywhere else in the year. Until Piltdown man was proved to be fake, the model lead scientist in human evolution for the next decade.

                Human beings are susceptible to their own faults. In the case of the Piltdown man several human flaws come to mind: jealousy, pride, optimism, trust, reputation, recognition to name a few. All of these played an important part in the Piltdown hoax of 1912. The first to speak of could be reasons for motive: jealousy, reputation, and recognition. All of these human feelings can be taken into consideration when looking at the suspect list. Scientist in England may have felt jealous that they were not making great finds like neighboring countries, therefore creating this scheme so they could prove their worth in the scientific community. Reputation and recognition go hand-in-hand with the motive as well, not only to credit England with having ancient remains, but also to provide the support needed for Author Keith’s theory that humans’ developed larger brain sizes prior to walking upright. If the Piltdown man was real the findings would have credited Keith’s theory and provide the evidence he needed. The other traits, optimism and trust are not so much flaws, but rather human’s necessity to want to believe in something amazing. I think that Woodward and others in the community at the time were optimistic in the findings and had high hopes for the new breaking evidence to human evolution. Trust plays a role as well because when you have trust worthy people involved in something it makes it easier to believe that to be true. When you tie all of these human feelings together it can be easy to see how human nature played a heavy role in the Piltdown hoax, playing off human emotions rather than scientific evidence.

                About ten years later, in the 1920’s scientist were digging up remains in Asia and Africa that were less human, not more human, yet were relatively younger than the Piltdown man remains found in England. While these remains lead to questions of the Piltdown mans authenticity or evolution path, the technology was not available during the time to fully study the bones. After WWII a new technology was created that allowed scientist to measure the fluorine content in fossils allowing them to give the fossils a date.  The test is called a fluorine analysis and was conducted on the Piltdown fossils in 1949. The fluorine analysis showed that the remains were only around 100 years old, rather than the previous claim that they were 1 million years old.  In 1953 scientist conducted an even more thorough exam of the fossils with better dating methods. The exam revealed that the staining on the bones was superficial, materials were cut with a steel knife after being fossilized and the teeth in the jaw showed groove lines providing evidence that the teeth were filed down to make them look more human. Belonging to a female orangutan, the jaw bone was modified to make it look less ape-like in shape and the canines were filed down to make them look more human. After the extensive examination, scientist concluded that the Piltdown fossils were not real.

                Anytime humans are involved in anything it is inevitable to avoid the human aspect that occurs. It is human nature to have errors, egos, optimism, ambition, curiosity, greed, etc.  In science the opportunity to have human error is present as well, yet there are ways, methods, to help limit human error in science. The scientific method is a very strict and rigid method which regulates scientific hypothesis testing and is universal in the scientific community. Since this method is accepted universally it greatly reduces human error in science. That said the human factor in science is important to have because without it there could be the potential for scientist to miss something that they would have otherwise overlooked if nobody ever made a mistake. If mistakes were not made, complex analysis would not occur, if more extensive research was not perform than the scientist would/could miss important breakthroughs that could have significant impacts in the scientific world. For this reason and more, the human factor in science cannot and should not be removed.

                The lesson learned in the Piltdown hoax is that even the most morally based professions can become vulnerable to personal bias, agendas, and gain. Humans are capable of failing themselves and their profession if the reward is profitable and lucrative enough for a small few. The Piltdown hoax serves as a learning tool to not accept things for face value just because a selected few support the findings. It is a learning tool for scientist to be more thorough in their investigations. This lesson can be carried outside the scientific realm and applied throughout many aspects of everyday living from the politicians we follow, the doctor’s advice we take, and the food and products we buy. Do not take for face value what unverified evidence gives us, instead do your own research and find the truth through credible sources.  

Comparative Primate Blog: Comparing Primates through the defining trait of body size and Sexual Dimorphism

1-3. Comparing Primates through the defining trait of body size and Sexual Dimorphism

a.       Lemurs (Prosimians/Strepsirhini): Lemurs live on the island of Madagascar and the nearby Comoro Islands.  The island is located in the Indian Ocean of the eastern coast of Africa. The location of the island allows for tropical climate along the coast as well as inland, yet arid in the southern part of the island. The climate allows for two seasons: hot, rainy about half the year and cool, dry the other part. The geography includes many rivers and lakes, coastal beaches and central highlands. Madagascar has a unique and rare variety of species. Since the island separated from Africa about 65 mya, it does not have many of the large mammals or poisonous snakes found on the continent, making it a hotspot for new species to evolve. Lemurs have evolved to become fit for living on the island. Their body and behavior is different from other monkeys throughout the world.

“A World Apart”

b.      Lemurs vary greatly in size, they can be anywhere from 1.1 ounce to 15-20 pounds and seem to the smallest of all living primates. However an extinct Lemurs species, the Archaeoindris fontoynonti, could range from 350-440 pounds. The ring-tailed lemur has a black and white striped tail on both males and females. Male ring tailed lemurs have dark colored scent glands located inside their wrist, chest, and armpits. Females and males both have anogenital scent glands. Male and females are the same in size growing to around 1.39 feet and weighing around 4.87-4.89 pounds. Other variations of lemurs have more noticeable Sexual Dimorphism in the color of their fur. The male black lemur is completely black while the females display a white collar around their face and have white on their chest. The rest of her body is a reddish color. Another lemur that has this white marking on the female is the mongoose lemur. Other than this, Lemurs seem to have developed traits allowing for Sexual Monomorphism.

c.       Since Lemurs where secluded from other primates on the island of Madagascar, they evolved differently due to the seasonal changes on the island, which create a larger diversity within the clade of Lemurs. Isolated, there was not much in the way of competition and the Lemurs used their intelligence over other species on the island which lead to their successful diversity. Before humans learned of Madagascar about 2000 years ago, some Lemurs grew to the size of gorillas, but today those larger Lemur primates are extinct and there remains about 100 species of Lemurs. The harsh weather of Madagascar accounts for the fur that Lemurs have developed. Also they have a trait for seasonal fat storage. Resource limitation and seasonal breeding also account for the Sexual Monomorphism, creating little to no differences between male and female phenotype. The diet accounts for their stature too in that they live on mostly fruit and leaves. Most Lemurs are arboreal which accounts for their small sizes, but the Ring-tail Lemurs are terrestrial which explains why these Lemurs are so much larger in size.

d.      “Lemurs: Spirits of Madagascar”

Ring-Tailed Lemur

Mongoose Lemur

a.       Spider Monkey (New World Monkey/ Platyrrhini): Spider Monkeys live in tropical rainforest of the central and Southern parts of America and can be found as far north as Mexico. Spider Monkeys tend to stay high in the tree-tops and eat the variety of fruit and leaves found in the rainforest. Central America is prone to earthquakes as well as volcanoes. It also has large mountain rangers and fertile valleys lying in between them. The climate is generally associated with tropical to sub-tropical allowing for a rich landscape with a variety of flora. The rainforest provides homes for a large variety of species as well, including dangerous predators such as large cats like Jaguars and Pumas. With its dense forest and Amazon River, the rainforest is home to about 30% of the world’s species. Unfortunately, deforestation is threatening the biodiversity of the worlds Eden because of the cultivation of soybeans and cattle. Every year the Amazon loses an area of forest the size of New Jersey!

“The Last Eden”

b.      Spider Monkeys are relatively small for primates. The largest Spider Monkey is the Black Spider Monkey with males weighing about 23.8 pounds and females around 21.3 on average. The height for the male is around 1.83 feet and females average 1.81 ft. There is not really a noticeable Sexual Dimorphism in Spider Monkeys size. Male and females seem to be relatively the same; females are only slightly smaller than their male counter-parts.

c.       Spider Monkeys tend to be small to accommodate their arboreal lifestyle. The size allows them to move in the forest tree-top. They have long arms and prehensile tails that allow them to grip tree, which allows them to move freely. Their weight is taken into consideration here for their ease of movement. Also, spider monkeys have a high caloric which encompasses their dependency on fruit. They must be able to travel freely and widely to accommodate their demanding diet because of the scarcity and wide-spread resources to eat in their habitat.

d.      “New World Spider Monkeys”

Black Spider Monkey

a.       Baboon (Old World Monkey/ Cercopithecidae): Baboons are found in the sub-Sahara in Africa as well as some Arabic regions. The sub-Sahara has harsh climates and is separated from Sudan by the Nile River. Baboons prefer the savanna and other somewhat humid atmospheres. The savanna is a grass land area with trees that are too small to create an enclosed canopy, but in some places has some pretty dense forest. There is a seasonal water supply so availability is small. The area comprises about 20% of the earth’s surface and the land transitions from forest to desert.  The savannas are threatened by wildfires, human clearing for cultivation, and human induced climate changes through greenhouse gases.

“Land which is without trees but with much grass”

b.      Baboons vary in size. The Guinea baboon is 20 inches long and weighs about 28-57 pounds, while the larger chacma baboon can be 47 inches tall and weigh up to 90 pounds.  Baboons are marked with sexual dimorphism.  The males tend to be larger than the females and the females and young baboons are dependent on males for protection. Males are often twice the size of females and are more aggressive. Females have pink rumps and males have a mane of fur around their heads. Male baboons have long canines used to fend off predators and to compete with other males. Females have sex skins around their private parts and are developed during ovulation time to let males know she is ready. The forelimbs and hind legs on a baboon are equal in length, making it hard to climb.

c.       Baboons are terrestrial which accounts for the large size and relatively equal length forelimbs and hind limbs. They are omnivores and can eat just about anything including fruit, roots, and grass seeds and leaves. They also can eat small mammals and invertebrates. Their environment is not one needed for high tree living so Baboons evolved into larger mammal and they have more resources of food. Large Male baboons have evolved the canines to hunt other monkeys , gazelle, or flamingos for food.

d.      “Old World Baboons”

Female Baboon with swollen sex skin 

Male Baboon showing canines and strength. Also notice equal size forelimbs and hind limbs

a.       Gibbon (Lesser ape/ Hylobatidae): Gibbons inhabit parts of China, Southeast Asia, and islands, like the Philippines and Singapore. Southeast Asia has two regions, Mainland and Maritime. The climate is mainly tropical-hot and humid all year round; however, in the higher mountain ranges the weather is dry and desert like. There is also plenty of rainfall with accounts for the diversity of species because the area is vulnerable to monsoons. The rainforest is the second largest on earth, second to the Amazon. Loaded with predators and prey, Southeast Asia is home to tigers, rhinoceros, elephants, Gibbons, Eagles, six subspecies of Binturong, Komodo Dragons, and more. The biodiversity in Southeast Asia is amazing. The forest floor is immersed in nutrients which allow thick forest growth. Unfortunately, the rainforest of Southeast Asia is a victim of the “slash and burn” cultivation and is facing extinction, along with its many species. Some have predicted that 40% of the region and species will be wiped out in the 21^st century.

“The land of Plenty (Monsoons)”

b.      Gibbons are known as the lesser ape because they only reach about 3 feet in height and 12-20 pounds, which is small for an ape. Gibbons do not have too much sexual dimorphism in the way of size other than the siamangs, whose males get to about 30 pounds.

c.       They are arboreal and are the fastest of tree dwelling creatures. Their small, compared to most apes, stature allows for them to move bipedal at times and swing with great ease through trees. Gibbons have evolved a ball and socket joint with allows for biaxial movement. This allows the Gibbons to swing while reducing stress on the upper body and arms. Some of these evolutionary traits can be tied to the environments monsoons and the predators around the floor, posing threats to the Gibbon which keeps them high in the trees.

d.      “Gibbon: The Lesser Ape”

a.       Chimpanzee (Great ape/ Hominidae): Live in the middle region of Africa. Typically Chimpanzees prefer tropical environments like the rainforest, but you can find Chimps in the savanna forest and the montane rainforest. The montane rainforest generally has cooler temperatures in higher mountain regions. The common chimpanzee however lives in the lowland rainforest south of the Congo River. The great rainforest basin from the Congo River is found throughout middle Africa. The large forest of the region allows for plant diversity with well over 10,000 species. The biodiversity of plant life provides home and shelter for many species, including four from the great ape family, elephants, buffalo, bongo, hogs, etc. Unfortunately these animals fall victim to bush meat hunters which is posing a large threat to the biodiversity of Africa’s middle region.  In addition, because of the rich soil this area is good for cultivating cocoa, coffer, and rubber. There are environmental concerns about the deforestation occurring through the lumber business and farming.

“Cloud forest and Congo Basin”

b.      Chimpanzees can reach to about 5.6 feet in height. Chimpanzees are sexual dimorphic in that the males weigh around 150 pounds and female tend to be around 100 pounds and are less muscular. Males are more aggressive than females and tend to eat more meat than females. Females’ behavior is different in that they leave and find new mates while males generally stay with their natal community to help protect their territory.  

c.       Chimpanzees are both arboreal and terrestrial. Chimpanzees have the ability to climb trees and walk on the ground either by “knuckle-dragging” or bipedal. Since they dwell on both the ground and in the trees their body size accounts for predators on the ground while giving them ease of maneuvering through trees. The difference in the behavior of staying and leaving the natal community is evolutionary in that the female goes off in search of a mate, to procreate, while the males stay to protect their food sources and territory. This is a strategy used to sustain their species and is a great example of sexual dimorphism created out of necessary evolution to the species survival.  

d.      “Common Chimpanzees”

Female Chimpanzee with infant

Male Chimpanzee with toddler

4. The research and comparative traits of the five primates through body size and sexual dimorphism has shown that there is a definite link between how a species evolves in their respective environment. The primates that tend to be smaller, Lemurs and Spider Monkeys, are arboreal and live on a mostly fruit diet. Their habitats are tropical, with thick forest growth. The larger primates, Baboons, Gibbons, and Chimpanzees tend to be arboreal and terrestrial which allows us to see why they grow to be much larger in size. They also seem to be more omnivorous than the smaller primates which accounts for why they are larger, not only through nutrition, but also because of the necessary strength needed in obtaining prey. While the Gibbon and Chimpanzees inhabit tropical forest regions like the smaller primates, they are adapted for ground living and tree living. Baboons live in an area that is not so dense populated by forest which accounts for their canine teeth and their hindering ability to climb trees. After the extensive research for this post it is interesting to look at the common environments of each primate and the differences to compare and contrast why those primates have evolved so differently with respects to their needs in their own ecological niches of the world. The primate I found to be the most interesting is the Lemurs of Madagascar because they, being separated from all other primates, found their own way to evolve through natural selection.

Homology/Analogy Blog Post

1.      Homologous trait shared between Whales and Chimpanzees

a.       Whale is a generic name for a group of marine mammal, including dolphins, porpoises, sperm whale, killer whale, pilot whale, and beluga whale, to name a few. Whales are decedents of land-living mammals from the Aritodactyl order. Whales evolved from Ambulectus going fully aquatic about 5-10 million years ago. Whales, like mammals, are warm blooded; they nurse their young, have hair, and have lungs which breathe air.

Chimpanzees are members of the Hominidae family, along with humans. Chimps live on land and walk upright on two legs when carrying things. They are covered in black hair with a bare face, fingers, toes, and have palms on hands and feet. They have strong family bonds and wean infants by about three years old, maintaining a close relationship with their children. They reach puberty around 10 and generally live to around 50 years old. Chimpanzees live in West and Central Africa and are currently, sadly, on the endangered species list.

b.      Homologous trait: One aquatic and one land living:

The homologous trait between the two species is their forelimbs. Whales and Chimpanzees, along with humans, birds, and reptiles, all share a common four-legged ancestor, the tetrapod. Having lived over 365 million years ago the tetrepod is a common ancestor that is responsible for the forelimbs found in the listed groups, including whales and chimpanzees. Whales’ forelimbs are structured as flippers. They are a flat broad limb adapted for swimming. Whale flippers differ slightly between each sub-category of whales. For instance killer whales have Pectoral flippers with a skeleton of forelimb land mammals.  Their flippers are rounded and paddle like, used for steering and stopping. They have a thick cartilage that pads the bones. Humpback whales have flippers with bumpy edges, yet provide the whale the ability to channel flow and increase aerodynamic efficiency. The structure of the whales forelimbs are greatly different to that of the chimpanzees in that the skeletal structure is padded by a cartilage and rough, rigid surface forming a rounded shape. The function is different because whales use their forelimbs to help them swim and maneuver through water. Chimpanzee’s forelimbs are structured the same in that they have the same skeleton structure humerus, ulna, radius, carpals and phalanges, but they are housed differently which accounts for the different functions.  Chimpanzees’ forelimb skeletal structure is housed in muscle, flesh and fur. The phalanges are detached allowing for fingers on the palmed hand. The elbow joint moves too, just as a human. These structural differences allow for the difference in function. Chimpanzees use their forelimbs for climbing trees, carrying things or babies, and for walking.

c.       Whales and Chimpanzees are ancestors from a four-legged animal called the tetrapod, which produced the forelimb homologous trait found in these species. A tetrapod are vertevrate animals with four limbs, so I know that the tetrapod had that trait.  

     d. Pictures

Killer Whale

Humpback Whale

Chimpanzee

    

2.      Analogous trait shared between Sugar Gliders and Flying Squirrels

a.       A Sugar Glider is a small gliding possum and originates from the marsupial family, like kangaroos. They live in the eastern and northern mainland of Australia as well as New Guinea. They have a squirrel-like body with a long tail. They have five digits on each foot, equipped with claws. They have large eyes and the females have a marsupium, (pouch) for carrying their babies because marsupial species give birth to babies who are not fully developed.  

The name, Flying Squirrel, can be misleading as they are not capable of actual mechanical flight like birds, but they are capable of gliding. They live in North America and are part of the placental family. They bare a strong physical appearance to Sugar Gliders in that they have a tail and five-digit feet with large eyes. They do not have a pouch however because mammals in the placental family give birth to fully developed babies.

b.      Analogous trait: Both gliders, yet not from the same family.

The analogous trait shared by Sugar Gliders and Flying Squirrels is the thin piece of skin that stretches from their feet to their hands, allowing the small fur balls to glide from tree to tree. The trait of “wings” evolved in each species independently as a product of their environment. Both species are tree dwellers who adapted the paper-like wings to allow a gliding movement from on tree to another. Flying squirrel produce more lift and less drag with their wings than Sugar Gliders and they have a well-developed propatagium in the structure of their forewing. Sugar Gliders have this as well but it is smaller. Regardless of size and performance, both the Sugar Glider and the Flying Squirrel have this trait which allows them to glide in their environment.

c.       Sugar Gliders, from the marsupials family, and Flying Squirrels, from placental, are thought to have come from a common ancestor over 100 million years ago and independently evolved ever since.  The group was mammal which diverged into the two groups, placental and marsupials. According to a website at UC Berkley “Since sugar gliders and flying squirrels are very distantly related [100 mya], it seems very unlikely that their common ancestor had flaps of skin stretched between its legs…. Instead, each lineage probably evolved the trait independently as adaptations for gliding and tree-living” (evolution.berkley.edu). The quote basically explains that because these mammals lived so far apart and branched off from their common ancestor over 100 mya, than the probability of having an ancestor possessing the “paper-wing” trait is highly unlikely. It is more likely that the Sugar Glider and the Flying Squirrel, through parallel evolution, evolved with “wings” to be more “fit” for their environment.  

d.       Pictures

Sugar Glider

Flying Squirrel