The cold is an environmental stress that we are all exposed
to at different levels and at different lengths of time. This environmental
stress has a negative impact on humans and their survival. In order for people
who live in cold climates year round to have the best response to the climate,
their evolution includes more compact bodies with more mass. In order to help
keep the bodies temperate at a high enough degree, the blood vessels within the
body begin to contract and become smaller, this helps with core temperatures.
Because of such extreme cold temperatures, the body has to work harder to
maintain a warm enough core temperature all while given the individual its
normal function in order to survive.
People who live in this conditions constantly tend to drink
alcohol to warm them. This is only a temporary solution and can cause a faster
death from hypothermia. Alcohol is only a short-term solution because its
effects wear off quickly. Culturally, individuals try to keep warm by wearing
warmer clothes (things such as furs) and making sure their homes are insulated
and are safe to have fires inside to keep them warm. Another type of adaptation
that has been made is biological. Human bodies over time in cultures who are
exposed to extreme cold have a fatty layer of insulation around their vital
organs, they have an increased basal metabolic rate, and a long term change in
their pattern of blood flow. The consumption of high calorie foods also
helps. IF individuals become too
cold and frostbite or hypothermia sets in, these individuals loose fingers,
toes, and limbs their ability to hunt and gather food, make warm clothing, and
build fires would decrease as would their survival.
It is important for us to study human variation across
environmental clines for several reasons. This type of information can help us
learn how different humans adapted over time to different climates; it helps us
to see why others might not have survived. When we study clines we can see over
time how adaptations evolved and this information can help us when we study
other adaptations.
We see different adaptations in different places across the
world. Different skin tones, eye colors, fingerprints. While today our society
focuses a lot on different races and how we look from one another, these
differences were not made to separate us from one another. These differences were
adaptations to our climates and environments based on where and how we lived. By
looking at clines of weather we can see why and how these different “races”
evolved so that they could survive and live in their specific climate.
Here are some photos of different adaptations in individuals
living in cold climates:
Photos courtesy of: Britannica.com
Your point is well made about how what appears to be race related differences are simply adaptation differences. I will also note that the things you point out are clear examples of evolution. The fact that people who live in cold climates clearly have adapted by forming fatty tissue around their main organs seems to me to be huge in evolution. Very interest post - filled with facts!
ReplyDelete"This environmental stress has a negative impact on humans and their survival."
ReplyDeleteYes... but how? This was the information that needed to be provided in this first section, explaining cold stress negatively impacts human homeostasis.
The guidelines ask that you identify four specific adaptations: short term, facultative, developmental and cultural. Other than cultural, I don't see the other adaptations you list identified as any of the other three types.
You mention vasoconstriction. This is a short term adaptation.
Drinking alcohol is maladaptive. It is not an adaptation to cold climates as it only gives the illusion of warmth. In reality, it actually causes the core body temperature to drop and it reduces mental acuity which will make it harder for the person to solve this problem of cold stress.
Increased basal metabolic rates is a facultative adaptation to generate more body heat. Increasing body mass and changing body shape can be a facultative trait if it occurs after a person has moved into a cold climate. If it is a genetic trait possessed by a person in a population living in cold environments over many generations, this would be a developmental trait.
Good cultural discussion.
I agree that using the adaptive approach can help us better understand human variation but how can this knowledge be used in a concrete, productive way? How about the production of better clothing that protects us from cold stress?
I agree with your points in the final section, but are you suggesting that you can't use race to better understand human variation? Is there no way to study human variation from the basis of race?
Great post. I believe that alcohol only gives the person who's drinking it the illusion of being warm. In actuality their body temperature is the same which can definitely lead to hypothermia quicker since they are unaware of how cold their body temperature really is. I did not know that a fatty layer of insulation develops around vital organs within populations who are exposed to cold temperatures. With an increased metabolic rate the body produces more heat. However as a result of this it is necessary that the body does consume high calorie foods like you mentioned in order to fuel the rising metabolic rate. What kind of changes do we see in people's blood flow who live in constant cold conditions? Do these changes in blood flow help reduce the risk of hypothermia or frost bite ?
ReplyDeleteI also think that when we study human variation in regards to race it is important to keep in mind that every different "race" is a group of people who adapted to their environmental conditions years ago. I think that if we look at it this way it can help reduce racism and show as you said that these differences do not separate us from each other.
Good job, I really enjoyed reading this response. Your example of alcohol was a very good example of a short term adaptation, but what kind of action does the body take to keep its self warm temporarily? all of your other examples were very well thought out and i felt they had a lot of scenic backing to them. All and all, excellent blog.
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