Human Variation & Race: Cold
The cold is an environmental stress that negatively impacts the survival of humans by disturbing homeostasis (regular even body temperature). When it gets too cold outside, the body will automatically turn on a switch that will try to maintain the body temperature at 98.6 degrees (normal body temperature). The cold tells your brain that it’s cold which results in your body trying to adjust and make changes for surviving the cold. One gets some of this ability or energy to stay warm/ or remove warmth through the nutrients taken in and stored in the body from food or what’s called metabolic heat production. Think of food as fuel the body needs fuel to survive and function properly. That’s why it’s so important to eat healthily and regularly. We have seen this lately as it’s been unusually cold here in Southern California. The news mentioned more people getting sick and catching colds. It’s partly due to our bodies not able to maintain homeostasis. The cold effects the ability for your inner organs, skin tissue, and blood to work properly. If your body can’t adapt, then one may suffer from hyperthermia and potentially die.
Four ways in which humans have adapted to the cold:
Short-term adaptation
Our bodies try to acclimate to the cold by producing metabolic heat production. A process that allows your body to maintain normal temperature (98.6 degrees). This can be demonstrated through shivering. This allows one to use energy to maintain warmth.
Facultative adaptation
When one is in extremely cold weather, the body tries to keep warm through what is called vasoconstriction. This is where the blood vessels narrow in trying to keep the warmth in due to contraction from the muscular wall of the blood vessel.
Developmental adaptation
In regards to developmental adaptation, you’ll notice that body size plays a huge part with individuals who live in the colder climates. People tend to store more weight in colder climates. They tend to eat more fatty foods. This allows for their basal metabolic rates to rise allowing them to store more energy which produces heat and will keep them warmer. Natural selection plays a part also because while people relocate from warmer climates to colder climates, the body requires different types of warmth. Natural selection enables people to adjust and acclimate to their surroundings to survive.
Cultural adaptation
Cultural adaption to the cold can be considered the clothes we wear. People who tend to live in warmer climates will tend to dress differently than those who live in colder climates. Individuals will tend to wear heavier sweaters, gloves, jackets, and scarfs. This is culturally acceptable because to stay warm, one must insulate themselves to try to keep heat in. Columbia sportswear provides what is called Omni-tech which is special technology that’s designed to keep heat in and moisture out for those who plan on being in colder areas.
There are several benefits for studying human variation from this perspective across environmental clines. For example, if one decides to venture out to Oregon in the winter, it would be good to know that the climate drastically changes from L.A.’s 70 degrees to potentially below 30 degrees. With this information, one can prepare ahead of time so they won’t get caught without the necessities to be able to keep warm. Knowing that one will need to stay warm and take the needed precautions or else they might result in hyperthermia would be a benefit. Also, because we never know what to expect in any situation, it’s always good to prepare for the worst. With that in mind, trying to accumulate necessary stuff for the “just in case,”. It’s always good to be prepared for unexpected environmental conditions. Better prepared = to survival.
I would use race to understand the variation of the adaptations only to study ancestral reasons to what differentiates human physical characteristics and their adaptability throughout the different regions/ climates. I would indicate that humans are characteristically different depending on where their ancestors lived and describe how natural selection has played a part in their survival, but also show that not every race shares the same/exact characteristics. For example, why do those who live in colder climates tend to be heavier in weight and why does their diet look different than those in warmer climates. These are ways the study of environmental influences on adaptations is a better way to understand human variation than by race because as we relocate all over the world, we will eventually share similar/ different adaptabilities which differentiate ourselves from others who may be our same race.
The key to the danger of cold stress is in the last couple of sentences in your first paragraph when you say "The cold effects the ability for your inner organs, skin tissue, and blood to work properly." References to the body adapting, food intake and getting sick are all secondary issues. The impact of cold stress on homeostasis is the drop in body temperature alone which slows blood flow to the body, making the heart work harder. With less blood flow, organs start to fail, including the brain, and thinking becomes more sluggish as thinking (necessary to escape the problem) becomes more difficult. If the drop in temperature continues, it leads to complete organ failure and eventually death.
ReplyDeleteGood explanations for your short term and facultative trait.
For your developmental trait, you talk about a person "gaining weight" in cold weather, but remember what a developmental trait is. A developmental trait is something a person is born with, not something they can develop, adjust or create during their lifetime. So what you are actually describing is more accurately a facultative trait. But you can also notice that populations in cold climates tend to have shorter, rounder body shapes, in agreement with Bergmann and Allen's rules. This doesn't talk about the trait changing in a single person, just what the trend of the population is.
Good cultural adaptation.
I agree that knowledge is always useful from a personal perspective, but can you identify a way this knowledge can be useful in a concrete way that benefits humans in general? 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?
"I would use race to understand the variation of the adaptations only to study ancestral reasons to what differentiates human physical characteristics and their adaptability throughout the different regions/ climates."
That is just using the adaptive approach and layering race over top of it. Is it really possible to use race to explain human variation? It is important to recognize that the answer to this question can be "no".
Race is not based in biology but is a social construct, based in beliefs and preconceptions, and used only to categorize humans into groups based upon external physical features, much like organizing a box of crayons by color. Race does not *cause* adaptations like environmental stress do, and without that causal relationship, you can't use race to explain adaptations. Race has no explanatory value over human variation.