Cold; An Environmental Stress
Long term responses to the cold can vary and long term exposure can not only be dangerous for humans, it can be fatal without adequate adaptation. An example of how too much exposure can negatively impact the survival of humans by disturbing homeostasis is when an individual develops Hypothermia; a life threatening drop of core body temperature to subnormal levels. Normally temperatures in humans are around 98.7 degrees (F) and while there are several factors, (e.g. metabolism, hormone levels, physical activity or depending on the time of day) that can cause temperatures to rise or decrease by a degree or so, hypothermia occurs when the core body temperature drops to 94 degrees (F). If adequate adaptation has not occurred the body temperature can continue to drop and failing to stay above 85 degrees (F) will cause the hypothalamus to fail, which will then in turn cause rapid cooling of the body. Likely resulting in death.
Short Term Adaptation
Our bodies have ways of rapidly responding to cold, and one way that we adapt in the short term is by shivering. Shivering is an involuntary response where we shake slightly and uncontrollably thus increasing internal heat production by generating body and muscle heat.
Facultative
Another way our bodies respond to cold is by way of a facultative response called Vasoconstriction. Vasoconstriction is a more energy efficient condition that rather than producing heat to combat the cold, it helps us to minimize heat loss. The process involves the narrowing of our blood vessels near the skins surface which preserves our core body heat by reducing peripheral blood flow. Provided that temperatures do not drop to the level of hypothermia, the skin will remain cool, which will in turn prevent heat loss at the body surface.Developmental
Two significant developmental factors that effect how we physiologically respond to the cold were addressed by a 19th Century naturalist named Carl Bergmann; aptly named Bergmann's Rule. According to Bergmann's Rule body size and shape are the defining factors in combatting the cold. For example, in animals, those that had greater mass and bulk to their make up were found to be in
While there are less productive ways to culturally respond to cold, (e.g. drinking alcohol), I am going to focus on the following fundamental idea: insulated housing. When accessible, we humans have the ability to shelter ourselves in our homes, perhaps curled up in a blanket by a fire to keep warm. Cuddling up with loved ones can also help to minimize heat loss.
I believe the benefits to studying human variation from this perspective across environmental clines are that we are able to learn how our bodies can respond physiologically, whether it's by retaining heat or increasing heat production. Information obtained while studying this variation can he helpful in the future by knowing what factors will be needed when traveling to other destinations where the elements are far colder than what we're used to. Because we have now studied this type of variation and adaptations to this variation, we are now armed with the knowledge of what symptoms to look out for and to potentially be able to recognize dangerous developments or responses that might occur when exposed to colder climates. For example, I now know that when I am shivering it's my body's way of trying to help me by trying to produce body and muscle heat and that it isn't necessarily a red flag behavior.
Race as a classification alone should not be used to categorize humans, as we are not distinguished by characteristics or traits from one race to the next. Race was a concept that evolved to give reason to be able to deny rights and freedoms to some, while empowering others. Our genetic traits are inherited independently of each other and all humans have all evolved from our earlier ancestors. From a variation study point of view, race has no biological validity. The study of environmental influences on adaptations is a better way to understanding human variation because we can study the genetic make up of an individual as well as the environmental factors that may play a role in the variation type. Learning how those who came before us adapted or how those in colder climates adapt can lend to our being more prepared in the future. Studying how our bodies react to the cold in conjunction with our developmental and cultural responses is what gives us insight to human variation and our race has no bearing on those responses.
Good, thorough discussion on the dangers of cold stress.
ReplyDeleteWell done with all four of your adaptations, though I do need to caution that drinking alcohol is NOT adaptive to cold stress. It can actually put you into danger in cold stress. Fuzzy socks and a roaring fire are much more adaptive.
I agree that knowledge is always useful, but can you identify a way this knowledge can be useful in a concrete way? Can knowledge on adaptations to cold climates have medical implications? Help us develop clothing that retains heat more efficiently? Can we develop new means of home/building construction that might help increase heat retention? How can we actually use this information in an applied fashion?
Correct, race is a social construct, not a biological one, but more importantly, it does not *cause* our adaptations, as the environment does. As such, without that causal relationship, you can't use race to explain why variation exists.
Hello Acorn Gazette!
ReplyDeleteYou have a very good and informative post! I like how you mentioned in the end that race is a social concept, not a biological one. I myself seemed to not make this clear in my own post and accidentally left it out. If I have discussions such as this in the future, your own statement aided in how I should phrase it. I agree that fuzzy socks, coats, scarfs, and other forms of clothing are definitely cultural adaptations to the cold weather. Very nice post.
Hello! Great utilization of shivering to explain one of our body’s short-term responses to a low temperature environment! It makes me think about how this adaptation came to be, what causes us to shiver when we aren’t cold? I know most of us have experienced shivering as a stress-related response to something eerie, so it makes me wonder if there is any relation to the same shiver we get when exposed to the cold. We do use shelter in order to survive, but there is a lot more cultural importance to these structures than you mentioned here. For example, the look, texture, size, and even down to the paint can say a lot about a person’s perspective and cultural take on the world. I like how you mentioned cuddling! I completely agree with you when you say, “Race was a concept that evolved to give reason to be able to deny rights and freedoms to some, while empowering others. It’s hard not to think that there is a correlation between higher levels of intelligence, and being able to see people for who they really are. Scientifically, our only differences are simply found within human variations of survival. Culturally, so many people are still too far behind to realize this.
ReplyDeleteHi Anita,
ReplyDeleteI would like to point out that your four examples were easy to understand and informative. My favorite was cultural; I like how you mentioned that we have the option of insulated housing. While I was reading that segment, I can picture myself sitting next to the fire with a blanket. When you mentioned that "we are now armed with the knowledge", I agree. I find it important that we stay aware of our surroundings and learn how to deal with certain situations. The shivering was a great example you provided. As you mentioned, your body is trying to keep you warm but it is also telling you that something is wrong and need to be warmed.
As far as race, I liked how you mentioned that race is a concept. I hope in the near future other people can see that race has no biological ties. Race has been used to make people feel inferior to others and that has to change.