Human Variation

  In the cold, the body has two homeostasis responses to the cold by increasing heat production or heat retention.  Heat retention requires less work from the body so this is normally the quickest and earliest response.  Heat retention is energy that the body retains from food.  Unfortunately, during the winter or in colder climates food is usually scarce.  If the body is not receiving enough heat the body will go into increased heat production.  Examples of this would be shivering, which is only short term.  Vasoconstriction is another short term response that minimizes heat loss.  Vasoconstriction narrows blood vessels to constrict blood flow from the skin.  Therefore reducing the amount of heat lost at the surface of the surface of the body.  

  Using the environmental stress I discussed above, shivering would be considered a short term adaptation for humans under cold stress.  Shivering does not require genetic change and is a quick response to colder temperatures.  

  I have also mentioned vasoconstriction above.  This is a form of facultative adaptation in humans for cold stress.  We depend on our bodies for warmth.  Sometimes our body uses vasoconstriction to narrow our blood vessels to reduce blood flow to the surface of our body keeping the body from losing any more heat.  It serves as a heat trap within the body.  

    Metabolic rates allow us to retain certain amounts of food for survival.  Humans who must survive in chronically cold conditions have metabolic rates to help gain body fat as a form of heat retention.  The Inuit people who live in the Arctic originally had the highest protein and fat diet of any population.  They did this to allow their body to develop other methods for survival. 

  Cultural adaptations to the cold would be the clothes that we wear, like snow pants or hats and gloves.  Other versions of cultural adaptations to the cold would be the ability to migrate like birds.  Many people who live in relatively cold areas are known to migrate at a certain time of the year if their other obligations allow them.  Migration patterns could be passed down through generations which is why this form of adaptation is considered important just like the others.  

  Studying and understanding human variation and why variations occur can help other people better understand different environments and different cultures.  If people of the Inuit tribe decided to travel from the Arctic to a souther Caribbean Island, knowing and understanding different types of adaptation would help them survive the travel and help it be more enjoyable.  Someone who grew up in the desert like flat grounds of New Mexico can use these tools if they decide to take a winter trip to the mountains.  

  

  Many people often use skin color or other phenotypic traits as a way to study or explain human variation.  The people that have similarities with each other in those categories are put into categories called races.  Although race seems to be a way to study human variation, I personally do not see how this would be useful.  Race is usually a social significant term used to express a persons biological phenotype.  You can have multiple people of multiple different races in a certain environment, so using environmental adaptations proves to be the best way to study human variation.