Human Variation

Environmental Stress: Heat

Heat is an environmental stressor that can be detrimental to the human race, possibly even resulting in death. Although adapting to the cold weather is more difficult psychologically then adapting to extreme heat conditions, more people die from heat then they do from intense cold. Hyperthermia occurs when the body temperature of a human rises to 105-107 degrees Fahrenheit. When an individual experiences this type of heat paired with humidity, the body cannot cool itself by releasing sweat, due to the fact the sweat can no longer evaporate because of the humidity surrounding the individual. However, in dry heat, the sweat is evaporated too quickly, resulting in the body losing the needed water and salts from the body. Hyperthermia can result to death in a matter of a few days, or even as less as 24 hours.

Adaptations

1. Short-term: Evaporative cooling is a physiological mechanism in which the body helps prevent itself from overheating. Perspiration is produced from sweat glands and then evaporates from the surface of the skin.

2. Facultative: Vasodilation is the expansion of blood vessels, permitting increased bloodflow to the skin. This is an involuntary response to warm temperatures, which warms the skin and facilitates radiation of warmth,  as a means of cooling.  Blushing is an example of this.

3. Developmental: One example of this is body size and proportion, to regulate body temperatures. For warm temperatures, the ideal body shape is linear with long legs and arms, because it promotes heat loss.

4. Cultural: The use of clothing one example of a cultural adaptation. The Tuareg who inhabit the nations of Mali, Algeria Niger and Libya, wear loosely fit clothing and head scarfs, which covers most of their bodies. This allows their skin to be safe from the heat radiation, while also giving air flow to the skin to allow necessary sweat to occur.

Although most of us have the ability to adapt to extreme heat sources, we do not know the cultural aspect of this stressor. I believe cultural adaptation is the most important when it comes to heat. It is very important to know the ways of the people who live in these climates on a day to day basis. If we are ever in a climate or environment of this sort, it is not only important for us to be able to use our natural adaptations, but it is also important to know the cultural aspect of it as well in order for survival.

In researching and conducting this blog post, I can now truly understand why it is much more important to study environmental influences on adaptations, rather than the race of the humans whom reside there. Each and every one of us, regardless of skin color or background, all have the ability of evaporative cooling and vasodilation, which are extremely important tools when dealing with extreme heat temperatures. Although we cannot necessarily change our body type, this is something in which is developed due to a need of survival in a certain climate. In this case, it is a tall and slender body type, which can reduce heat. However, this is not developed due to race, it is developed due to environmental influences. In order to develop any of these adaptations, you do no need to be a certain race, it is a matter of adapting to a certain environment in order to survive. Overall I have come to the conclusion that race does not aid in helping us understand human variation.

Piltdown Man: Fact or Faked?

The Piltdown Hoax

The Piltdown Hoax was one of the biggest hoaxes in the history of science, and is what I believe to be one of the reasons we now have the scientific method in order to prove an hypotheses. The Piltdown Man, was an supposed finding of an piece of a primitive man’s skull, and later findings of a jaw bone and teeth. This Piltdown man was found in the 1900s in Sunnex, England, by a laborer which was digging in a nearby town, named Piltdown. The piece of the skull which was found, was then passed on to Charles Dawson, a nearby archaeologists. Dawson then spent all summer digging in Piltdown, searching for another piece of the puzzle, which he did find, the jawbone and teeth of the Piltdown man. At this point in time, Charles Darwin’s theory of evolution was simply a theory, with no facts to back up his hypotheses. Without any fossils of early humans or apes, there was no evidence to support the theory of evolution. However, this new found fossil of the Piltdown man, was about to change science and evolution in its entirety. The Piltdown Man was considered the missing link which connected humans and apes, the answer needed to prove evolution.

Due to the hype of the possible change in evolutionary history, the scientists and archeologists involved in this finding, may have overlooked many important factors in their studies. Rather than jump to the conclusion that they had indeed found the answer in which connected humans and apes, they should have made sure they had absolute proof of their findings. I feel they should have took the time to really research and study the fossil more thoroughly, before announcing their findings to the public. I believe the excitement and the view of the public eye had in turn skewed their decision making abilities when it came to the scientific findings.

In the 1900’s, the technology in which we have today, did not exist or even come close, leaving these scientists and archeologist without any of the necessary tools to prove the authenticity of the fossil they had found. But in 1953, the Piltdown Man was further investigated, and proven to be a fake. A chemical test was done to find the nitrogen content, which would in turn reveal the date and authenticity of the fossil. It was found that the Piltdown Man, which was said to be over a half a million years old, was in fact not that old at all. Not only was the time off, but after being studied under a microscope, it was also found that the teeth had been filed down and the remains were not even human. These fossils were fakes, they had been tampered with to look older and human like, and were also planted at Piltdown. The man found responsible for this mess was not the founder of these fossils, but a man named Conan Doyle, who was himself had an interest in fossils. But why would this man create such a hoax in the scientific community? It is believed this act was committed because he himself was embarrassed in the scientific community, and it was almost a way to get back at those who had shunned him and his beliefs.

The main factor in the Piltdown Hoax was the human aspect. On one end we have scientists which believed what they saw, rather than putting much research on their findings, while we also have an angry scientists and author who basically set up these scientists for failure. These reasons are what I believe to be why we now have the scientific method in order to help prove a hypothesis. Although the use of the scientific method does not necessarily mean that a hypothesis and a study will be proved true, it does help weed out the unnecessary human factors which can lead to an occurrence like the Piltdown Hoax. In using the scientific method, the findings must be falsified and throughly researched and studied by scientists other than the ones who have performed the study or experiment.

The Piltdown Hoax is an example of why you cannot always believe what you hear or see. Although we would like to think that something is true if it was discovered by a scientist which has thoroughly studied an issue, this is not always the case. It is always important to look at both the pros and cons of a situation and way the facts at hand, in order to draw our own conclusions, not rely solely the on the conclusions of others.

Homologous Versus Analogous Traits

Homologous Trait
One example of an homologous trait, is the forearm. Not only do humans posses this trait, but cats, whales, horses, birds, bats, and all other vertebrate do as well. Although the trait contains the same type of structure, the forearm itself serves a different purpose for each animal which posses this trait. The purpose of the forearm results in the different needs of survival of each animal and their habitat. For whales the forearm is used for swimming, for bats and birds it is used for flying, for horses and cats it is used for running, and for humans it is mostly used as a way to bend the arm itself.



Analogous TraitsAn example of an analogous trait in two different species is the claw of both the scorpion and the crab. The crab can live on both land and in the ocean or other water source, while the scorpion usually resides in a desert terrain. Both use these claws for the same purpose, such as eating and defending themselves from predators. Not only do these two species use their claws for the same purpose, the shape and proportion of the claws are almost identical to one another. However, these two animals are considered two different species, the scorpion being an insect and the crab being a crustacean. They both come from the ancestor, Anthropoda, as shown in this courses text Introduction to Anthropology.

Protein Synthesis Blog

Good luck cracking the code!

CGCCTCCCCTACCACGAGTAAGCCAACACCGGCATATTGATCCTTCAGCGT