An environmental stress that can negatively impact the survival of humans by disturbing homeostasis is heat. Heat can negatively impact the human body by causing heat exhaustion. Heat exhaustion happens when the body has lost too much fluid and salt. You start sweat excessively, feel fatigued, and nausea may set in. Heat exhaustion can then turn into heat stroke which can be dire.
One way the human body can adapt to heat for a short amount of time is by sweating. When the body starts to sweat it releases heat. The sweat cools down the body through evaporative cooling. Evaporative cooling is when sweat evaporated off the skin causing the skin to cool down.
A Facultative adaptation humans have for heat is vasodilation. Vasodilation is when capillaries that are close to the skin open up close to skin so heat can be lost through the skin.
A developmental adaptation to heat that humans have is, bipedalism. Bipedalism is a locomotion that means an organism that walks on two limbs instead of four. Since humans stand on two feet less sun is able to hit our bodies all at once making it easier for the body to stay in the shade and staying cool.
A cultural adaptation to heat would be air conditionings. Air conditionings work by drastically cooling down a room or building on a hot day. By having a cooler environment the body is able to relax once out of the heat.
The benefits from studying human variation from this perspective across environmental clines is that we mass amounts of different information that helps us become knowledgeable on how to survive in hot climates. Because of this information we know how to properly take care of ourselves like staying hydrated and not overworking ourselves.
I would not use race to understand the variation of race i listed in question number two because the color of someone’s skin has nothing to do with helping the body cope from heat stress. Skin color can help with radiation and blocking uv rays and it cannot block out heat.
Hi Kelsey,
ReplyDeleteI also chose to write about heat stress. I enjoyed your post and especially liked how each adaptation has a simple but informative description that makes it easy for the reader to understand.
Good, focused explanation on the negative impact of heat stress on the human body.
ReplyDeleteGood explanation for your short term and facultative adaptations.
Heat stress is one possible explanation for bipedalism, but it has a lot of challenges to it and not a lot of support. The biggest problem is that there are many, many organisms that have been faced by heat stress on the African savannah. Why would only human adapt via bipedalism? More that likely bipedalism arose due to other selection pressures, but well done including this as a possible adaptation.
I agree that knowledge is always useful, but can you identify a way this knowledge can be useful in a concrete way? Can knowledge on adaptations to hot climates have medical implications? Help us develop clothing that release heat more efficiently? Can we develop new means of home/building construction that might help decrease heat retention? How can we actually use this information in an applied fashion?
"I would not use race to understand the variation of race i listed in question number two because the color of someone’s skin has nothing to do with helping the body cope from heat stress."
First of all, racial categories are based not just upon skin color but also phenotypic features, such as facial features and body shape. That said, in equating skin color with race and saying it doesn't influence adaptation to heat stress, you are making an important point that there is no causal relationship between race (and the features that shape these categories) and human variation. Interestingly enough, to argue that race DOES have an impact on human variation is to argue essentially that human variation (in the form of race) shapes human variation... which is just clearly absurd. Does that make sense?
Race is not based in biology but is a social construct, based in beliefs and preconceptions, and used only to categorize humans into groups based upon external physical features, much like organizing a box of crayons by color. Race does not *cause* adaptations like environmental stress do, and without that causal relationship, you can't use race to explain adaptations. Race has no explanatory value over human variation.
Kelsey, I did heat on mine too! Your writing was very organized and easy to read. You were very informative in your post and I enjoyed reading it and comparing it to what I wrote for heat. You gave good information on each adaptation. Great choice of images as well!
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