Human Variation and Race 

Cold 

1.In past chapters we have discussed that early hominins evolved from Africa, the warm-to-hot woodlands and savannas of East Africa. This plays a against humans survival in cold weather because we come from ancestors that were adapted to heat , so the body had to adapt to this weather making the body due more work with populations living in cold weather. Living in cold weather requires the body to create more energy because the body needs to either retain heat and/or increase the heat production.For the body to produce more energy it requires a good diet, which during the winter can be a problem because the food in not as abundant, due to cold weather not as many food like fruits and vegetables grow. 

2.Humans have adapted to this stress in different adaptions: 

• Short -term adaptation 

A short-term adaptation to cold is shivering. shivering generates muscle heat. When the body is exposed to col weather the body temperature drops and in response the body shivers to help maintain homeostasis. The shivering helps the body to raise its temperature. 

Another short-term response is the metabolic rate, where the cells break up nutrients into their components and release energy in the from of heat. The body wants to conserve energy and heat and for that reason in cold environments our metabolism is slower. 

• Facultative adaptation

Facultative adaptation involves turning on and off genes that alter phenotypic expressions in response to an environmental stress. In the case of cold weather vasoconstriction is the facultative adaptation because is an involuntary response to cold that depend on the skins surface. Vasoconstriction restricts capillary blood flow to the surface of the skin and this reduces the loss of heat at the body surface. 

• Developmental adaptation 

Developmental adaptation are traits that we are born with and once they are expressed we will live with hem for the rest o four life. A great example of developmental adaptation is the rule of Bregmann, where he states that animals with larger bodies are generally more massive and produce more body heat. Our ancestors relied on their subcutaneous fat layer as protection for cold weather but also as a type of back up source when food was scarce. 

• Cultural adaptation: 

The Inuit are people living in the Artic,they had a carnivorous diet because of their hhigh animal protein and fat diet.  Due to the environment in which they lived, they didn't have access to fruit and vegetables, so they based their diet on what was available to them. The fat they gained from the animal consumption provided them the energy and carbohydrates they needed to be able to survive in the cold. 

3. The benefit from studying human variation is that we learn how and why different people from different places acquire different customs and ways of living. We are able to understand that we are all the  same but  have to look for different ways to survive in the different environments the world offers, nobody is special in any way we are all the same and some of our features are there, the way we look is sometimes related to a survival trait. 

4. The use of race helps understand the variation of adaptations because people from different places adopt different customs and and different phenotypic traits that help them survive in the environment they are born in, and this different customs an traits is what makes race. The study of environmental influences on adaptations is a better way to understand human variation than by the use of race because race is a main focus on to classify people into groups that depend on skin color, common language and ancestors and this could lead to racism, on the other hand the environmental influences on adaptations explain the reasons and the way people are different from each other, how and why they got to that point , making it clear that we are equal and the way we look and behave is related to a way of surviving.