Human Variation and Race

Human Variation and Race Blog

High altitude affects the survival of humans negatively because even though high altitude and the sea level have the same percentage of oxygen, high altitude’s air pressure is 30% lower because the atmosphere is less dense.  This means, that the air molecules are farther apart.  At high altitudes, since the air pressure is lower it makes it more difficult for oxygen to enter our vascular systems and the result of this is hypoxia or oxygen deprivation.  Hypoxia usually starts with not being able to do normal physical activities such as climbing a set of stairs.  There can also be a lack of appetite, distorted vision, and difficulty with memorizing and thinking clearly.  In some serious cases, high altitude can lead to a fatality if the person cannot acclimatize correctly.  This environmental stress negatively affects the survival of humans because our body is not equipped to handle such drastic climate changes.  Our body is more susceptible to health problems in higher altitudes because of the fall in atmospheric pressure. 

Our bodies do a short-term adaptation to high altitudes by acclimatizing itself.  Acclimatization is where our bodies produce more red blood cells and capillaries to carry more oxygen.  Our lungs will increase their size to facilitate osmosis of oxygen and carbon dioxide.  The vascular network of muscle, which enhances the transfer of gases, also increases.  

A facultative adaptation that our bodies do when going into higher altitudes is producing more hemoglobin to carry oxygen throughout our bodies.  In order to do this you would need to take iron capsules.  Iron produces hemoglobin.  In doing this you are helping your body acclimate to high altitudes by not stressing the body to much to produce more blood cells and capillaries to carry the oxygen.  

Humans that is more likely to be able to develop in a high altitude area better than most is someone whose ancestors have lived at high altitudes for thousands of years.  Since some peoples ancestors lived in high altitudes for so long, they are usually genetically more suited for the stresses at high altitudes. The solution for the Indians in the high mountain valleys of Peru and Bolivia has been that they are able to produce more hemoglobin in their blood and to increase their lung expansion capability.  Both of these things results in an increase of oxygen that is carried by the blood.  Tibetans and Nepalese live in higher altitudes and they generally breathe faster in order to take in more oxygen and to have broader arteries and capillaries.  This allows an increased rate of blood flow and subsequently greater amounts of oxygen delivered throughout their bodies even though they have relatively low hemoglobin levels.

There is considerable variability between individuals and between populations in their ability to adjust to the environmental stresses of high mountain regions.  Since some peoples ancestors lived in high altitudes for so long, they are usually genetically more suited for the stresses at high altitudes. The solution for the Indian in the high mountain valleys of Peru and Bolivia has been that they are able to produce more hemoglobin in their blood and to increase their lung expansion capability.  Both of these things results in an increase of oxygen that is carried by the blood.  Tibetans and Nepalese live in higher altitudes and they generally breathe faster in order to take in more oxygen and to have broader arteries and capillaries.  This allows an increased rate of blood flow and subsequently greater amounts of oxygen delivered throughout their bodies even though they have relatively low hemoglobin levels.

A cultural adaptation that many people who climb or hike to higher altitudes for enjoyment or to conquer a goal they have set for themselves, have started using oxygen tanks.  The oxygen allows them to climb to higher altitudes without experiencing severe hypoxia symptoms.  It also helps the body to not work as hard to produce more red blood cells and capillaries to carry more oxygen.

One of the benefits of studying human variation from this perspective across environmental clines is that, researchers believe that people generally live longer at high altitudes and have a lower risk of dying from coronary artery disease. This positive effect occurs unless people have chronic breathing problems. The researchers speculated that mild hypoxia improves the way the heart functions and produces new blood vessels that increase blood flow for the heart. Another explanation is that increased exposure to ultraviolet radiation from the sun at higher altitudes might increase the body’s ability to produce vitamin D, which has beneficial effects on the heart.

I wouldn’t use race to understand the variation of the adaptations.

Language Assignment Experiment

Part 1:

For the first part of this experiment, I found it extremely difficult not to speak. I use my hands all the time when I talk so that was easy for me. My partner and my 7 years old daughter had a very hard time understanding me. I almost felt like I was playing a game of charades. It was frustrating, because I couldn't explain my thoughts using only my hands, body language and face expressions. My daughter tried to figure it out what I tried to say, and "translate" it, but after couple of minutes she started to give up and she got annoyed with the fact that I could not speak. My partner and especially my daughter are the types who like things verbalized and explained to them and I was unable to speak, so it became frustrating for them too.

Part 2:

For the second half of this experiment, I had a hard time not using my hands. This experiment was harder than I thought. I had to start over two times, because I forget not to use any non-verbal language. Normally I use hand gestures almost every time I speak. Through this experiment I just realized how often I use and rely on symbolic language. I ended up having to sit on top of my hands and not moving. My daughter enjoyed more the conversation with me, because I could speak, but at the end she thought that this "game" was to boring. The most difficult part of this experiment was that I actually had to concentrate on not moving my head or giving attitude with my body language or using my hands. I felt almost trapped not being able to use any type of symbolic language.

I think that the use of "signs" in conversations is very important. They can add meaning to verbal language. The symbolic language or non-speaking language can be very effective in communication because it gets the points more than just verbal speaking.

Some people have difficulty to read body language. I used to have a friend who didn't get my messages through my body expressions and he asked me all the times about the meanings of them. I think if you can understand and speak others language and you are also able to read their body language then you have quite a bit of an edge over others. Being able to read body language helps to know how to take a comment or a conversation and to know what people are actually meaning and not insinuating what someone means.  I think that the type of environment where the body language is not so important is in the conversations when we can not see each other (talking on the phone, being in dark or in different rooms...)

Piltdown Hoax

1. The Piltdown Hoax was found in Piltdown, in the rolling hills of Sussex, a rural county in southeast England in the early 1900’s. A laborer was digging at Barkham Manor, near the village of Piltdown, found a strange peace of skull. He gave it to Charles Dawson, a local amateur archaeologist. When the Piltdown man was first found, the scientific community was ecstatic.  They thought that Dawson had found the missing link between humans and apes.  Dawson and Sir Arthur Smith Woodward were digging for a summer and found an ape-like jawbone with human-like teeth that seemed to link it to the skull. On December 18, 1912, they presented Piltdown Man (“the earliest Englishman”) to the world. Some scientists wondered if this jawbone and skull were really from the same creature, because a crucial piece, the canine tooth, was absent. Dawson and Woodward with an amateur French archaeologist, Teilhard de Chardin found the missing teeth a year later in Piltdown. In 1917 Woodward announced the discovery of a second Piltdown Man.

In 1953 they announced that the Piltdown Man was fake. This discovery was embarrassing for the British scientists. Kenneth Oakley applied a chemical test to authenticate and date the fossils. The mineral department on the behalf of the Natural History Museum tested the nitrogen content. The tests showed that the Piltdown Man was much younger than expected.

There were many suspects of the hoax: Sir Arthur Conan Doyle, Dawson, Woodward and Martin Hinton Woodward’s rival at the Museum, but the identity of the Piltdown hoaxer has remained a mystery.   

2. One fault that I believe played a factor in this scenario was rivalry.  I think rivalry played an important factor because Britain and Germany were rivals and wanted to bid up each other wherever and whenever they could.  Britain wanted to prove that they were the first birthplace to the human race.  Dawson was known to be an ambitious man and he may have wanted to be the first Englishman to find the first fossils.  I also think that too many people were involved in this hoax to be recognized and gain titles. 

3. Scientists ended up discovering the hoax when they started to look more closely at the fossils.  They did a fluorine test that measured the fluorine content on the fossils so that scientist could roughly date the age of the fossils.  The remains showed that they were rather young.  They then launched a full-scale analysis on the fossils.  It showed that the remains had been stained and were superficial and the material had been cut when the bones had already been fossilized.  The scientists then looked at the Piltdown mans teeth under a microscope and saw that the teeth had been filed down to look like human teeth.  The jawbone that was with the Piltdown mans skull was that dated back less than 100 years and was a female orangutan jaw.  They also noticed that bones had been removed to make the jawbone look like it belonged. 

Scientist before the hoax had their doubts.  As I stated previously the jawbone was that of an orangutan and the teeth, which belonged to an ape, had been filed down to portray human teeth.  Scientists increasingly regarded Piltdown as difficult to interpret and inconsistent with the path of hominid evolution as demonstrated by fossils found elsewhere.

4. The definition of “human” factors from science is understanding the properties of human capability.  So in my opinion I do not think that it would be possible to take away the “human” factor to reduce the chance of errors.  I say this because in order to try and understand why someone would try and pull of a hoax of this magnitude you need to have an understanding of humans and their behaviors.  Without that I think that it would be hard to figure anything out in this world whether it has to do with science or not.  I personally would not want to take the “human” factor out of science.  Humans play a role in science in almost every situation. 

5. One life lesson that I can take from this historical event and just the world in general is that being greedy does not help you. Dawson or the mystery man wanted to be the first to discover the Englishman fossils that could have been the first link between humans and apes.  However, at the end it was proven that the fossils were fake and too young. If someone tries to mislead people, the truth would come on the surface sooner or later. In this case it took about 40 years to discover the truth.

Primates - Locomotion

Lemurs (Posimians/Strepsirhini)

Environment:  Lemurs rule the treetops of the tropical rainforest. Many species live in Madagascar’s tropical rainforests, but some live in dry deciduous forests.

Locomotion: The locomotion behavior of lemurs depends upon the species. The below table is a quick study of what type of locomotion behavior is and was exhibited by different lemur species.

Lemur Species	Locomotion Behavioral Characteristic
Indris	Vertical clinging and leaping
Bamboo lemurs	Vertical clinging and leaping
Mesopropithecus	Slow arboreal quadrupedal
True lemurs	Fast arboreal quadrupedal
Ruffed lemurs	Fast arboreal quadrupedal
Ring-tailed Lemur	Partially terrestrial quadrupedal
Monkey lemurs	Highly terrestrial quadrupedal
Sloth lemurs	Sloth-like suspensory locomotion

Lemurs are quadrupedal, they use all four limbs for locomotion. The lemurs’ strong hands and fingers help them to climb trees easily. Their muscular legs are adapted for jumping. When they need a change of scenery, they hop to another branch.

How locomotion has been influenced by its environment:

Lemurs adapted to their environment rather well.  Since they are either on the ground or in the trees the locomotion movement of Lemurs has adapted well to their environment.  They are able to move on the ground rather quickly and if need be can leap into the trees and have great balance.

Spider Monkey (New World Monkey/Platyrrhini)

Environment:  Spider monkeys live in tropical rainforests of South and Central America, from Southern Mexico to Brazil.  These new world monkeys live in the upper layers of the rainforest and forage in the high canopies.  Spider monkeys prefer large tracts of moist evergreen forests and they prefer undisturbed primary forests.  Spider monkeys are well adjusted to the life in the tree tops of the rainforest because they are strong and agile and can find food with the resources that they have. 

Locomotion: Spider monkeys use several different types of locomotion: quadrupedal, using all four limbs for locomotion as seen while walking or running; suspensory locomotion used when hanging, climbing or moving through the trees and bipedalism, using only two limbs when leaping. Quadrupedal locomotion is usually observed if the monkey is on a stable relatively substrate free of obstacles. When they are using suspensory locomotion they may be brachiating (swinging with their arms from one branch to another while often maintaining a tail hold).  The most commonly used pattern of body movement while in a feeding pattern is that of quadrupedal, climbing and suspensory locomotion. While traveling they mostly employ quadrupedal walking and running, suspensory locomotion and climbing.

How locomotion has been influenced by its environment:

Spider Monkeys locomotion was influenced by the primate environment greatly.  If this primate was not able to hang from a tree or able to swing from branch to branch and had to walk on the ground they would be more prone to being eaten by a bigger predator.  With the ability to hang from the trees and swing from the branches they are able to stay up in the high trees and keep themselves safe from the predators on the ground. 

Baboon (Old World Monkey/Cercopithecidae)

Environment: The two most common baboons occur in East Africa, the olive baboon and the yellow baboon. The larger and darker olive baboon is found in Uganda, west and central Kenya and northern Tanzania. Baboons generally prefer savanna and other semi-arid habitats, though a few live in tropical forests.  They are active at irregular times throughout the day and night.  In Africa, baboons can raid human dwellings and have been known to prey on sheep and goats.  Baboons are extremely adaptable, the major requirements that baboons need for any habitat that they are in is water, and safe sleeping places.  Baboons like to sleep either in tall trees or on cliff faces.

Locomotion: Baboon can and do climb trees to sleep, eat, or look out for trouble. They spend much of their time on the ground. Baboons locomotor pattern is quadrupedal and on their digits. Walking on their digits means walking on their toes with the heels not touching the ground.  This is known as being a digitigrade quadrupedalism.

How locomotion has been influenced by its environment:

Baboons walk on all fours and their digits which are the tips of their toes and the knuckles of their hands.  This locomotion trait I believe was adapted to help the baboons keep their hands and the soles of their feet from becoming to rough. They do not have prehensile tails. They spend their times mostly on the ground, but they do climb trees for sleeping, eating, and avoiding predators. 

Gibbons (Lesser ape/Hylobatidae)

Environment: Gibbons live in subtropical rainforests from northeast India to Indonesia and north to southern China, including the islands of Sumatra, Borneo, and Java.  Gibbons spend less than 1% on the ground, which helps to keep them safer.  Gibbons move from tree to tree by swinging their arms between branches.  Gibbons are arboreal animals, which mean that they spend the majority of their lives in the trees.  Living in the trees has its advantages for the gibbon as the gibbon has plenty of food and is also a safe distance above ground from predators.

Locomotion: Gibbons main locomotor pattern is brachiating.  When gibbons brachiate, they use four fingers of their hands like a hook; they do not use their thumbs.  Gibbons are known for being very acrobatic and agile.  Gibbons lives are spent mainly in the trees.  It is very rare for a gibbon to be on the ground but when they are they walk bipedally (on two legs).  Gibbons do not know how to swim, so they avoid water.  Gibbons are also able to walk along small branches high up in the air and stretch their arms out to help them keep their balance. 

How locomotion has been influenced by its environment:

Gibbons’ locomotion concentrates on the use of the arms for propulsion through the trees. The most extreme expression of this skeletal adaptation in living primates is seen in the modern gibbon family. Their forelimbs are relatively elongated, they hold their trunk erect, and for the short periods that they spend on the ground they walk only on their hind limbs. Living in the trees has its advantage of safe distance from predators.

Chimpanzee (Great ape/Hominidae)

Environment: The different subspecies of chimpanzees live in different parts of western and central Africa in 21 different countries, from the Atlantic coast to well inland. Chimpanzee’s habitats vary, but include dry savannas, evergreen rainforests, swamp forests, dry woodland and grasslands.  To be able to live in all different types of habitats chimpanzees have to be very adaptable.  Chimpanzees live in large communities ranging anywhere from 10-100.  Chimpanzees usually sleep in the trees as well, employing nest of leaves.

Locomotion: Chimpanzees usually walk using all fours (on the soles of feet and the knuckles of their hands). They can walk upright (when they need to use their arms to carry something), but usually don't. Chimps are also very good at climbing trees, where they spend much of their time, including when they sleep. They can swing from branch to branch in the trees.

How locomotion has been influenced by its environment:

Chimpanzee: locomotion trait has been adapted to the environment.  Chimpanzees are primates that can adapt to their environment really quickly.  The ways they move adjust to where they are living.  Chimpanzees are able to walk on all fours or if they need to carry food or something else they are able to walk on two of their limbs.  Chimpanzees are also able to climb trees and suspend themselves from branches.  The chimpanzee’s locomotion trait works to their advantage since they are able to adapt easily to any environment that they are in.  Chimpanzees are one of the few animal species that employ tools. They shape and use sticks to retrieve insects from their nests or dig grubs out of logs. They also use stones to smash open tasty nuts and employ leaves as sponges to soak up drinking water.

Lemur:

Spider monkey:

Baboon:

Gibbon:

Chimpanzee:

4. Summarize

The level of influence the environment has on the expression of physical and behavioral traits is a huge impact. The primates adapted to the environment that they live. 

Primates occupy two major vegetational zones: tropical forest and woodland-grassland vegetational complexes. Each of these zones has produced in its resident primates the appropriate adaptations, but there is perhaps more diversity of bodily form among forest-living species than among inhabitants.

Even though most primates are quadrupedal to some degree, many primates employ more than one form of locomotion.  Vertical clinging and leaping is a form of locomotion seen in many prosimians. Brachiation is a form of suspensory locomotion in which the body is alternately supported under either forelimb. Some monkeys are termed semibrachiators, since they use a combination of leaping along with arm swinging.

Within the forest there are a number of ways of moving about. An animal can live on the forest floor or in the canopy, for instance, and within the canopy it can move in different ways. In the woodland savanna, which substantially demands adaptations for ground-living locomotion rather than those for tree-living, the possibilities are limited.

Homogous and analogous traits

1.      a. homologous trait: four toes

Cat: The cat (Felis catus), also known as the domestic cat or housecat to distinguish it from other felines and felids, is a small furry domesticated carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests. Cats have been associated with humans for at least 9,500 years, and are currently the most popular pet in the world. Owing to their close association with humans, cats are now found almost everywhere in the world. (Wikipedia)

Lion: The lion is a species of the genus Panthera and its closest relatives are the other species of this genus: the tiger, the jaguar, and the leopard. Until the late Pleistocene, about 10,000 years ago, the lion was the most widespread large land mammal after humans. (Wikipedia)

      b. Homologous traits are those which species have in common because they have descended from a common ancestor. For instance, every species of cat has the homologous trait of possessing only four toes on its hind foot, because every member of the cat family descended from a common feline ancestor. The greater the number of such traits that two species share, the more closely they are related. A cat and a lion have more homologous traits between them than a cat and a human, for example—so cats and lions are more closely related, biologically.

c.    Feline was the common ancestor of these two species

d.    Lion, cat

2.      a. analogous trait: incisor teeth

Beaver: The beaver (genus Castor) is a primarily nocturnal, large, semi-aquatic rodent.  A beaver's teeth grow continuously so that they will not be worn down by chewing on wood. Their four incisors are composed of hard orange enamel on the front and a softer dentin on the back. The chisel-like ends of incisors are maintained by their self-sharpening wear pattern. (Wikipedia)

Elephant: Elephants are large land mammals in two genera of the family Elephantidae: Elephas and Loxodonta. Elephants' teeth are very different from those of most other mammals. Over their lives they usually have 28 teeth.The two upper second incisors: these are the tusks. Tusks in the lower jaw are also second incisors. These grew out large in Deinotherium and some mastodons, but in modern elephants they disappear early without erupting. (Wikipedia)

b. Consider the teeth of the beaver and the elephant. The gnawing front teeth of the beaver and the tusks of the elephants are both basically incisor teeth. While inherited in a basic form from an ancestor common to the beaver and the elephant, these teeth have been greatly modified by evolutionary mechanisms into the seemingly dissimilar teeth we see today in the beaver and the elephant.

c. I did not find common ancestor in my research.

d. Beaver, elephant

Protein Synthesis

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Historical Influence on Darwin - Thomas Malthus

"In October 1838, that is, fifteen month after I had begun my systematic inquiry, I happened to read for amusement Malthus on Population, and being well prepared to appreciate the struggle for existence which everywhere goes on from long- continued observation of the habits of animals and plants, it at once struck me that under these circumstances favorable variations would tend to be preserved and unfavorable ones to be destroyed. The results of this would be the formation of a new species. Here, then I had at last got a theory by which to work" (Charles Darwin, from his autobiography, 1876).

Charles Darwin was influence by many philosophers, economists and writers. One of his main influenced was Thomas Malthus, who wrote "Essay on the Principle of Population" (1798) The central theme of his essay was that human population growth would always overpower food supply growth, creating perpetual states of hunger, disease and struggle. So there will be competition and the most fit will get the food, reproduce, and spread their genes. The natural, ever present struggle for survival caught the attention of Darwin, and he extended Malthus' principle to the evolutionary scheme. Darwin considered that some of the competitors in Malthus' perpetual struggle would be better equipped to survive. Those that were less able would die out, leaving only those with the more desirable traits. Through his research Darwin concluded that this ongoing struggle between those more and less fit  to survive would produce a never-ending progression of changes in the organism. In its simplest form, this is evolution through natural selection.
Thomas Malthus's work helped inspire Darwin to refine natural selection by stating a reason for meaningful competition between members of the same species. He saw the concept relative to all species not just humans.
I believe that Charles Darwin couldn't  have developed his theory of natural selection without theories of Malthus, because before reading Malthus' ideas, Darwin had thought that living things reproduced just enough individuals to keep populations stable. He realized that the population theory could be applied to all aspects of organic life and provided a solid base in which natural selection could be studied.
Darwin had strongly believed in Malthus' theory and he used the population theory to help explain his own theory about natural selection in his book.

The church had extremely influenced on people in England in 19th century. Darwin knew that his theory which did not depend on supernatural processes would create problems. His ideas provoked a harsh and immediate response from religious leaders in Britain. They argued that his theory directly contradicted many of the core teaching of the Christian faith.
Darwin's work has helped fuel intense debates about religion and science then and now, so it's worthwhile to consider what his own religious beliefs were.

www.usmp.berkeley.edu/histrory/malthus.