Heat

1) Environmental stress: Heat. In severely hot climates, core body temperatures can rise to fatal levels. When body temperatures rise to at least 105 to 107 degrees fahrenheit, hyperthermia can set in which can result in death. Other things such as heat stroke and heat exhaustion can cause the internal organs to deteriorate and/or shut down.
2) Developmental adaptation: When living in areas where the air temperature is usually high, people tend to have longer limbs in order to release the most heat because longer limbs indicate more surface area and more surface area indicates a more rapid release of body heat.

Cultural adaptation: When people live in warmer climates, they tend to wear outfits that allow the most skin to breathe and release heat such as dresses, shorts, tank tops, flip flops, and swimsuits.

Facultative adaptation: When the skin is reddened due to vasodilation of the peripheral blood vessels it is because there is more blood closer to the surface of the skin, this blood allows heat to come up from the core body where it can then be easily released into the environment by radiation.

Short-term adaptation: Sweating is the production of fluids secreted through the sweat glands and it is a short-term mechanism used to release heat from the body.












3) The benefits of studying human variation from this perspective are that we are allowed to learn about how we, as humans, adapt to environmental stresses and it can demonstrate how we are more like other races than we might think. Instead of just observing that people with fair skin typically live in colder climates and people with darker skin live in more tropical climates, we can assess that it has something to do with the relationship between melanin and sunlight instead of it being race related. This type of information can be extremely helpful because we can learn biologically and physiologically why we react the way we do to certain environmental pressures. For example, learning why we sweat can lead to a number of things including learning how to prevent excessive sweating or how to regulate body temperature without it, if possible. 
4) Most Africans have long, slender limbs and bodies which I could attribute to their race rather than to the climate they live in which is generally warm. I could attribute vasodilation to white people because you can see the blood pigments easier through their skin. When using race to understand variations of adaptations, I am generalizing certain races by grouping them. For example, because most Africans are tall and slender I assume that this must be due to race but this is not true so race is an inefficient, unbiological, and generalized way to determine certain adaptations. The study of environmental influences on adaptations is a far better way to understand human variation because it reveals the biological and cultural reasons we react the way we do to environmental stress. It lets us know how our bodies are working and functioning internally and externally in certain situations. For example, the study of environmental influences can help inform us how and why our bodies react the way they do to high altitude pressures. Studies of the environment can also inform us on how natural selection works because it helps identify traits that thrive in certain climates or condition such as long limbs in warm climates.