Humans have many responses to the cold which we use to keep warm. Some provide short-term relief, while others are more long term solutions. Our text book states shivering and metabolic increases as two of our short-term reliefs (p.422). Shivering and exercise increase the blood flow and the core temperature of our bodies. The cost is the use of energy that we must use to make these things happen. To provide the energy we must make sure we increase the amount of nutrients we intake. Carbs and fats are necessary to maintain a level of energy to keep warm in the short-term. Another short term response in humans is vasoconstriction, in which the blood flow is restricted through the veins, slowing the heart rate and keeping the heat inside the body. In the long term, humans have built fires and layers of fat under the skin to keep warm.
The largest benefit of studying humans in this manner is that we get to see how they have adapted to their own environment. We can see how different people from different backgrounds are able to individually adapt. For example, if we study the development of sickle cell in certain populations and how they build up immunities, we can use this information to help prevent or treat sickle cell in other populations.
Race is not an effective way of studying human variation because we see immigration and migration world wide. Studying a general population based on environmental factors is a more effective way of determining what will happen to people who are born into or move into the same types of environments. We can compare results with other similar environments in other parts of the world.
It was very interesting reading about how cold temperatures affect the human body. There were a lot of good information you wrote and it was very detailed. I too wrote about how the extreme cold affects humans in my blog but did not explain it too well as you have. I learned a lot more now since I read your post.
ReplyDeleteI agree with your explanation that race is not an effective way to study human variation because of immigration and migration worldwide. People of different races eventually will adapt to whatever environment there are in.
I find it so interesting how little a change in body temperature can affect us. A drop of 4 degrees from 98.6 is only a 4% decrease in temperature, yet that small decrease can cause major damage and even death if prolonged. As annoying as shivering can be, I never really thought of how important it can be until now. Our bodies are so fascinating with how they automatically respond to things like the cold or heat without us having to consciously tell it to adapt to the environment. I agree that studying humans in this manner helps us to see how our own species has adapted to environmental stressors. Despite whatever race society groups a person, physiologically we are all similar in the ways we adapt to things like the cold.
ReplyDeleteGood initial discussion on the dangers of cold stress to human homeostasis.
ReplyDeleteYour coverage and explanation of short term adaptations was very good (though vasoconstriction is usually linked to facultative responses). However, the guidelines asked that you provide one example of each of the four types of adaptations to your chosen stress: Short term, facultative, developmental, and cultural. Missing the last three?
Good applied answer for the question of usefulness for the adaptive approach.
"Race is not an effective way of studying human variation because we see immigration and migration world wide."
Does that mean that 500 years ago, before there was wide-spread migration of human populations, race *would* have been a good way to study human variation?
Race is a sociocultural system of categorizing humans, defined subjectively based upon external phenotypic expressions. In other words, race is defined by natural variation in human populations. But you can't say that the other way around is true. Variation is not caused by race, and without that causal relationship, you can't use race as the basis for objectively understanding variation in humans. The environment, however, does cause that variation, so it can be used to understand variation.
Good post. I too did my study on cold temperatures and found it very fascinating. However, I do agree with the previous comments that facultative, developmental, and cultural adaptations were needed as well.
ReplyDeleteAlthough your first sentence of your final paragraph may be true, there are also many other reasons why we do not study variation based on race anymore. There will always be a certain amount of people that do not comply to every single aspect of the race and that is why we can not base variation off of race.
Overall, good post. I enjoyed the picture and think you did a good job.