Human variation occurs because of the
different types of environmental stress that take places and impact the human
race. The different types of stress that cause this impact are cold,
heat, high levels of solar radiation, and high altitude. I chose to explore
more about the stress that cold inflicts because I personally hate cold
weather.
Cold weather negatively impacts the
survival of humans because humans can only get accustomed to a very limited
degree of coldness, so if the weather is extremely cold, the human survival
rate decreases. Cold stress can lead to frostbite, hypothermia, and ultimately
death. Since we are of tropical origins it is even harder for us to adapt
to cold climates.
There are many ways in which we adjust
to the different type of environmental stresses that we might face, for
example:
1. Short
Term: Our bodies begin to shiver after
reaching a certain degree below the normal body temperature, after a certain
amount of elapsed time our bodies stop shivering and begin to suffer from
hypothermia.
2. Facultative:
People that live in cold climates
are already adapted to the cold. As time passes, the basal metabolic rate in
their bodies increases in order to adapt to the type of climate that they live
in.
3. Developmental:
Humans that live in cold climates
are more likely to have a higher amount of body mass than the average human in
order to hold in a higher amount of heat internally.
4. Cultural:
Diet can have a major impact
in the way species adjust, especially humans. The main diet for those that live
in cold climates is usually protein and fat because vegetation is pretty much non-existent.
As proven above human variation
allows us to see the difference in the human race not only physically but
culturally as well and how we may or may not evolve over time. Explorations
such as the one that we conducted today help us understand how others survive,
what we as a race are capable of and how to help others that may be in need but
that live under a different type of environmental stress.
I would use race to understand the
variation of adaptations if I was considering the entire human race as a whole.
If I was only dealing with one or two individuals I wouldn’t be able to
categorize by race because that’s dominantly based on skin color. The
study of environmental influences on adaptations is a better way to understand
human variation because different races can go under the same type of
environmental stress and same races can go under different types of
environmental stress, for example not all people from South Africa have dark
skin and dark hair, there are plenty of South Africans that I personally know
who have light skin, light hair and blue eyes but both groups are not
considered to be the same race.
I really enjoyed reading your post it had many things that were interesting to me that I did not find while doing my research.
ReplyDeleteI did not know about the part about when people live in colder climates their bodies adapt to it and increases their basal metabolic rate. very interesting. great job.
Hi Taline,
ReplyDeleteI also chose this adaptation because I too hate the cold! However, different individuals shiver according to how cold it is. For someone who lives in New York, for example, their definition of what is cold differs from ours. They're cold at 40-50 degrees, whereas people here in California are cold when it hits around 55-60 degrees (just a rough estimate).
Also, individuals who adapt to the cold adapt differently. For example, I just came back from Israel a week ago and I was shivering in 70 degree weather! Note that the Middle East is very humid and arid. I'm sure the lack of humidity out here adds to why I got so cold so easily.
Great post nonetheless! Great job.
Good opening explanation of heat stress and good short term trait.
ReplyDeleteFor your facultative trait: 'People that live in cold climates are already adapted to the cold."
I was confused by this statement as facultative traits will be expressed by those who do NOT live regularly in cold climates. So how did that pertain to this adaptation? Yes, increasing the basal metabolic rate is a facultative response but it is a slow one and will not help if temperatures plummet. An alternative adaptation that acts more quickly is vasoconstriction and then switching to alternative vasoconstriction/vasodilation to occasionally send blood and nutrients to the surface tissues. This still won't be enough to stave off tissue death forever, but it extends the survival time.
For your developmental trait, it isn't just an issue of body mass. Body shapes in cold climates are, developmentally, shorter and heavier overall. This is related to the fact that if the surface area of the body is relatively small compared to the body core (and relationship which produces a shorter, heavier body shape), that means less heat is lost from the body core since it is farther from the skins surface. Make sure you review Bergmann and Allen's rules that explain this relationship.
Okay on your discussion of the benefits of the adaptive approach, but one of the points I hoped to get across in this assignment is the problems with the use of the term "race", so I'm concerned that you are still using the term.
In your final section, you are using 'race' to refer to the entire species. This, technically, isn't using "race" to understand human variation. You are just using the term as a name. The version "race" that was the focus of this part of the assignment was the definition that acts to categorize humans into different groups based solely upon external appearances, such as skin color.
"If I was only dealing with one or two individuals I wouldn’t be able to categorize by race because that’s dominantly based on skin color. "
Actually, you would be able to categorize by race. The question is whose definition of "race" would you use. That is the problem with race. It is a social construct, subject to the biases and preconceptions of individual cultures, and it is designed to divide humans into categories, not to explain variation. It is not a biological/genetic construct, so how can it be used to objectively explain biological/genetic variation?
Missing images?
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