Week 8: Human Variation & Race-Cold

              Humans and other animals have migrated to many parts of the world, including colder climates. I chose the environmental stressor of the cold, in which humans and animals have adapted to internally regulate and survive these cold temperatures. First, humans in these climates face the dangers of developing hypothermia, which is when the body temperature drops to abnormally low levels posing danger to one's life and survival. The normal body temperature is 98.6 degrees Fahrenheit, while when hypothermia begins the body temperature drops to 94 degrees Fahrenheit and after 85 degrees Fahrenheit (below it) the hypothalamus fails to regulate the body's temperature and the body cools down quicker posing much danger. These low body temperatures may cause death and can only be revived if the body's temperature has dropped to the lowest of 57 degrees Fahrenheit. However, a bit more dangerous disruption to the homeostasis would be frostbite, in which the environmental temperature is below freezing point and the normal vasoconstriction is more prolonged causing the body to reach the point of frostbite. Thus, with these two disruptions of homeostasis in mind, surviving the cold would be difficult if we did not adapt.

        In order to survive and conquer through the colder temperature and climates, humans have adapted through short-term, facultative, developmental, and cultural adaptations. A short-term adaptation that allows humans to respond quickly to the cold to maintain homeostasis is shivering. Shivering may cause a short-term warming effect and its increased muscle activity produces some heat. 

             As a facultative adaptation to cold temperatures, which are genetic traits, an adaptation could be increased basal metabolic rate. When people traditionally consumed large quantities of fat-filled and high calorie foods they increased their basal metabolic rate that results in the production of extra body heat. As seen in the graph/image below the more weight, the more higher basal temperature, which produces more heat keeping the body warmer to colder temperatures. 

         Another adaptation called an developmental adaptation, an actual change in DNA of a population, in which could be for cold temperatures having a "stocky body with short appendages" which can be more effective with heat production because less surface area increases heat production. This according to Allen's rule would be an advantage to people in such extremely cold environments. 

       The last adaptation is called an cultural adaptations, which is the use of culture to adapt to environmental stress. In response to colder temperatures, as an cultural adaptation would be wearing heavy clothing as the Inuit (Eskimo) of the northern regions of the western hemisphere and the Indians of Tierra del Fuego at the southern end did to maintain body heat in the extreme cold temperatures.  Wearing thicker and heavy clothing shield the body from most of the cold temperatures of the environment and can promote heat production in the body. 

        By studying human variation from the perspective across environmental clines, we can learn how humans have adapted and evolved in order to survive different environments and geographical locations. Also, with this studying and knowledge, we can learn how our bodies have evolved to react to these stressors so that when we are pressured by the environmental stressor we will know how our body may react and how we need to ensure our body is trying to regulate itself or proceeding with homeostasis. For instance, if in Southern California a dangerous snow/ice storm struck out of nowhere, in which our bodies are used to heat and warmer temperatures, we may use this knowledge about these adaptations to see if our body is trying to regulate our body temperature. Also, if we see our body is being ineffective in regulating our body temperature, with the acquired knowledge from the studies, we may eat a fatty food to increase basal metabolic rate or wear heavy clothing as the Inuit in order to attempt to regulate our body temperature and ensure our survival from the extreme cold temperatures. Lastly, we can learn to differentiate when we our in danger of frostbite and how we can prevent this with our adaptations, in which can apply to any of the environmental stressors. 

     Race cannot be used to understand the variation of any adaptations because race is a socially constructed idea more than a factor we could use to study variation. We categorize and create the meaning of race, whereas the study of environmental influences on adaptations can give us more insight to human variation than race can. By studying these environmental influences we are able to see how different people in different environments react displaying variation rather than race, in which there can be many people in one area of different races that do not exhibit variation due to the environment. For instance, as mentioned before, those living in harsh subarctic regions, such as the Inuit, wore heavy clothing and slept in a huddle with each other in order to harness warmth and heat production. The Indians of Tierra del Fuego also exhibited these adaptations, showing how the environment shows the variation and clearly not the race of the people because race is a socially-crafted idea. 

Works Cited: 

"Human Biological Adaptability: Adapting to Climate Extremes." Anthro.Palomar. N.p., n.d. 

      Web. 05 Dec. 2016. <http://anthro.palomar.edu/adapt/adapt_2.htm>.