Low temperatures are disruptive to human homeostasis since the human body has a relatively high core temperature (97.7 Fahrenheit). Decreases in body temperature leads to impaired bodily functions. Slowed blood flow, lethargic nerve responses, and muscle rigidity are symptoms of the human body succumbing to the forces of cold temperatures. A human being has a low chance of survival of this homeostatic disruption persists since it essentially makes one "clumsy", a "clumsy" person has a lower chance of successful endeavoring for food and shelter.
2.
a) Short Term: Goosebumps are a short-term adaptation to cold temperatures. Goosebumps produce extra heat by the muscle tension created from piloerection. Additionally, raised hair also increases heat insulation. Shivering is another short term adaptation that functions in parallel to goosebumps.
b) Facultative: A major trait of many cold environments is typically the lack of sunlight, thus in areas where temperatures are typically below zero degrees, people tend to have lighter skin. This mostly due to the imperative of vitamin D absorption.
c) Developmental: A great example of developmental adaptability is the Inuit people and their consumption of high caloric fatty foods. This significantly rose their metabolic rates which as a result, their bodies produced more heat. They also have actively lifestyles which supplements their choice of diet and their bodies are stocky and round as a result.
d) Cultural: Igloos are actually incredibly effective insulators of heat since they are essentially traps for small pockets of air. Snow, despite being cold itself is great at insulation since it can be compacted to the point where there is almost nonexistent intrusion of cold air from the outside. Thus, body heat by itself, can be used to bring the internal temperatures of igloos to a comfortable 40 degrees Fahrenheit (much better than the alternative which is below zero).
3. There are many benefits to studying human variation through this perspective across varying environmental clines. One benefit is primarily medical, hypothermia and hyperthermia are two common medical conditions that can be fatal if not properly cared for. Observation of adaptations by humans living in environmental extremes can aid with the treatment of these ailments.
4. Race is an ineffective use of categorization since it has caused a lot of controversy for the majority of human history. From a genetic viewpoint, human beings aren't that different from one another. Phenotypic differences are a result from the environment in which humans have adapted to. It is a much more effective and efficient way to understand human variation through the perspective of environmental adaptation because it decreases the amount of classification we succumb ourselves to. If people had higher scientific efficacy and understood this about how environment plays a major role in how we look, I personally believe that racism would not be as big of an issue as it is today.
Very good description of the problems that arise due to cold stress. Good job focusing on the stress itself and not getting distracted by the adaptations.
ReplyDeleteShivering is an adaptation to cold stress. Goosebumps *used* to be an adaptation but not anymore in humans. Goosebumps form when the tiny muscle attached to the base of the hair follicle contracts, causing the hair to stand upright. Now if the organism has a full coat of hair, this causes and air pocket of warm air to form between the skin and the hair to act as insulation. But without that heavy coat of fur, we gain no benefit. We are left with only the bumps.
Skin tone is an adaptation to the level of solar radiation, either darker to protect against radiation damage or lighter to allow for the production of Vitamin D. This doesn't help with cold stress, however. An example of a facultative adaptation to cold stress is vasoconstriction to prevent heat lost through the capillaries near the skin's surface.
Diet is a little tricky with regard to adaptations. It isn't physiological, so is it a developmental/genetic trait? Not really. But it does contribute to the higher metabolism AND it helps Inuit populations maintain the rounder body shape that is a developmental adaptation to cold stress. Just make sure you understand the requirements and definitions of each of these adaptations.
Good cultural discussion.
Good response on the application of this knowledge to medical science. The medical implications could go beyond this, however, helping our understanding of how the body tries to preserve organ function selectively under cold stress. This could help us in cases when we need to slow body function to preserve tissues while slowing the advancement of disease during treatments.
"Race is an ineffective use of categorization since it has caused a lot of controversy for the majority of human history. "
Agreed, but race isn't ineffective because it is controversial. It is ineffective because it has no explanatory relationship with human variation.
"It is a much more effective and efficient way to understand human variation through the perspective of environmental adaptation because it decreases the amount of classification we succumb ourselves to."
I agree that it is more efficient and effective, but I would go farther and say that it isn't even possible to understand human variation via race. To understand why, you first need to understand what race actually is. Race is not based in biology but 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.
I completely agree with your discussion about how using race is ineffective aboviously deep down we aren't all that genetically different so that is why it isn't good to use race to understand the humana variation.
ReplyDeleteVery good blog. I like how you talked about igloos in cultural adaptation. I never thought about igloos when thinking about cultural adaptations. You are right thought that igloos keep a warm temperature even if they are made of snow.
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