Environmental Stress: Heat affects and disturbs human homeostasis
and also has affected the survival of mankind. The typical core temperature for
a human is 98.6 degrees Fahrenheit. When
human core temperatures elevate, the body can have hyperthermia, dehydration, heat
exhaustion, heat stroke and possibly death. Elderly and infants become more
affected as their tolerance is much lower than the average age adult.
Short Term: A gland in the human brain called the hypothalamus regulates
homeostasis of the human body. When
overheating, the gland instructs the body to sweat causing the air and fluid to
cool off skin. Other factors effecting the overheating of the body are related
to salt and water intake. Salt causes
the body to retain water, which is ideal when overheating because it decreases
dehydration related to overheating.
Facultative: Facultative adaptations caused by heat are skin tones.
An individual with a darker skin tone is likely to live or come from an area,
which has a very high air temperature and can absorb more heat without burning,
than an individual who has a lighter skin color.
Developmental Adaptation: A developmental adaptation we have developed
from heat is having less body hair. Our hominid ancestors had a lot of body
hair that kept them warm during the Ice Age era. One of the main theories to
why humans don't obtain much hair on our bodies today is because once the
hominids reached the desert areas in Africa, they started to lose all their
hair to keep their body temperatures cooler, to adapt to the warmer climate.
Cultural Adaptation: The creation of hats, cooler clothing,
umbrellas, insulation in homes and air conditioning has allowed individuals to
adapt to warmer climates and stay cooler. Meteorology is viewed and adapted to
accordingly.
Benefits: Individuals can benefit from studying weather variations in
order to prepare and discover forms of staying hydrated and cool. Products have
been created for the purpose of keeping our bodies cool. Learning from
experiences and technology will improve products and inventions to keep the
human body in homeostasis.
Adaptations: Reviewing environmental adaptations is an improved way to
explore human variation than looking at race because the environment is the
reason humans developed various skin colors, different physical characteristics,
and other creations that help human survive. Race is used to define a group of individuals who
speak the same language, use the same social practices, share religious
beliefs, and more. Adaptations can be traced further in history than the
variation of human race.
Great post and images! It is interesting how the hominids lost their hair and were able to adapt to their surroundings. It just goes to show that people are more adaptable then they think. Your viewpoint is very interesting on race and adaptation. "Adaptations can be traced further in history than the variation of human race." Well put. Good job!
ReplyDeleteThis post was very well done. I like how you took an in depth, scientific approach on explaining why humans sweat. Also, I never knew that darker skin tones absorb heat more efficiently than lighter skin tones. Also great images!
ReplyDeleteGood opening description of heat stress and its impact on the human body and homeostasis.
ReplyDeleteGood description of short term adaptations, just keep in that it is the evaporative effects of sweating that cools the body, not the fluid itself.
Skin color is an adaptation to solar radiation, not to heat stress. An example of a facultative response to heat stress is vasodilation which helps dissipate excess body heat.
Loss of body hair has been suggested as an adaptation to heat, and while it is an interesting idea, it does raise the question as to why humans are the only mammals to lose their hair in hot climates? So, yes, this is a possible heat adaptation... but possibly not as well! Body shape, specifically long, lean body shapes, are a developmental adaptation to heat stress.
Good discussion of cultural adaptations to heat stress.
Good explanation as to the practical applications of this type of approach to understanding human variation.
"Race is used to define a group of individuals who speak the same language, use the same social practices, share religious beliefs, and more. "
This actually defines an ethnic group, not race. Race is purely defined by external phenotypes, such as skin color and/or facial structure. But regardless, I agree with your conclusion as to the lack of value race has to understanding human variation. Race is a subjective social construct, not a biological one, so how could we use it to objective understand biological traits?
I'm not a big fan of heat because i love the cold weather so much but i still really enjoyed reading your blog. I always find it amazing how our bodies naturally know what to do when in certain situations as i was reading in your blog that our bodies will start to sweat to reduce heat. I also read on other students blog about the cold and they mentioned how our body creates heat when we shiver. i enjoy reading the different ways our bodies react to situations from you and fellow classmates. Great pictures by the way! It made your post even better.
ReplyDeleteJust living in California I worry about the exposure to both heat stress and high levels of solar radiation. It seems like they come hand in hand in some areas. Great job describing the adaptations to heat stress, but I wasn't too convinced about the skin tone thing on this one. All races can have light or dark skin tones for whatever reason, but according to the text resources skin tone is more related to sunlight exposure and altitude than anything else. But great pictures!
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