1. One environmental stress negatively impacts the survival of humans by distributing homeostasis is heat. Of course humans do need heat, but to only a certain extent, with heat being an issue it can cause a lot of problems with dehydration becoming easier to have and the loss of water because it would be evaporated. To compound the issue if there is no water for humans then there is no water for wild life and plants for humans to also eat as well. Humans can live without water for a certain amount of time, very quickly will our bodies start to break down, we won't be able to produce enough sweat or urinate at times. Of course if this type of situation occurs there will not be any other outcome, but death for humans.
2. A short term way that humans have adapted to heat is by sweating. When humans are in heat for a period of time the heat stays trapped in the body, but then is released by certain glands or pores in the skin that release allowing the body to cool off a bit and to not over heat, and after getting out of the heat the human body stops the process.
A facultative way humans have adapted to heat is having the blood vessels in the human body open and releasing heat through it for a long period of time, that's how people are able to live in places where it is very humid.
A developmental way of humans adapting to heat is by their body structure, before it was said that the first humans used to use all four limbs to walk, exposing their backs to the sun, but now since they have evolved to only using two limbs the heat stress on the human body is reduced allowing humans to be cooled off faster and easier.
Lastly, a cultural way humans have adapted to heat is by technology and having tools cool humans off much faster. The use of portable fans allow humans travel with a source that can keep them cool at anytime.
3. The benefits of studying human variation this environmental cline is great because it shows how much humans can adapt and see the changes affect humans physically as well. Information like this is very useful to us because it teaches a lot about how humans act in their certain environment. This information can be useful in how humans used to be when it came to heat and how it was an adaptation change for how humans walked up right showed a major change in adaptation.
4. When trying to compare heat adaptation to how the human race adapts to heat, it doesn't work and is completely opposite of each other. Humans are all the same in what they do, but the only difference is what there environment is what makes them different. Humans living in a more heated environment adapt better to it and humans living in a more cooled environment tend to live better there as well, but that doesn't mean they can't all adapt to different environments, it would just take time is all. Explaining why humans are the way they are is because of the environment they live in.
While it is true that dehydration is a secondary stress related to heat stress, it is primarily the result of the body trying to cool itself. Focusing on heat stress itself is a clearer way to understand how these stresses influence and shape human variation.
ReplyDeleteYes, sweating helps with heat dispersion, but the sweating itself doesn't get rid of heat. Sweat evaporating from the skin's surface is what actually removes excess heat from the body, i.e., evaporative cooling.
Good job on the facultative trait, but can you name this process?
Avoiding heat is one possible explanation for all humans being bipedal (one of many) but this is a discussion on human variation of modern populations. How have modern human populations developed/adapted genetically to deal with heat stress? Body shape (Bergmann/Allen's rules) are one example.
Good job on the cultural adaptations.
I agree with your conclusion in the section on race. You are right that race isn't capable of explaining the similarities and the differences between groups of people where the environmental approach can provide explanations.