Cold Life

Select only ONE of the following environmental stresses: (a) heat, (b) high levels of solar radiation, (c) cold, or (d) high altitude. Discuss specifically how this environmental stress negatively impacts the survival of humans by disturbing homeostasis. 

Cold climates create stress on the body that disturbs homeostasis by lowering our normal core body temperate range of 97.6 ˚- 99.6˚ to subnormal levels. When our core body temperate declines to 94 ˚, we begin to develop a condition known as hypothermia. Hypothermia occurs when our hypothalamus is unable to keep our core body temperate stable and we reach subnormal levels of temperature; cold climate is only one cause of hypothermia. Once our temperature decreases to extreme levels of 85 ˚F, our thermoregulation system fails and body temperature begins to drop rapidly resulting in organ failure and death. 

Symptoms range in mild to severe hypothermia. In mild hypothermia (89˚ -95 ˚), symptoms such as shivering, our blood vessel narrowing — vasoconstriction—, increase in heart rate, breathing and blood pressure and an onset of confusion and fatigue occur. In moderate hypothermia(82 ˚ -89 ˚), the shivering stops while confusion increases, metabolic rate drops, loss of fine motor skills, body alternates between vasoconstriction and vasodilation to avoid frostbite and gangrene (cycle is known as Lewis hunting phenomenon) and heart rate, breathing and blood pressure decreases. In severe hypothermia (<82 ˚), people experience extreme confusion and memory loss causing abnormal behavior such as taking clothing off, organs  — primarily the heart and liver — begin to shut down to conserve heat and protect the brain — causing irregular and/or weak pulse, slow brain activity and breathing — and a decline in consciousness which leads to a coma-like state and eventually death, as organs begin to fail.

Identify 4 ways in which humans have adapted to this stress, choosing one specific adaptation from each of the different types of adaptations listed above (short term, facultative, developmental and cultural). Include images of the adaptations.

Short term: Short term adaptations such as goosebumps, shivering, and cutaneous vasocontraction occur in response to cold weather. Shivering is the rapid movements of muscles as our body tries to produce more body heat; goosebumps occur when our arrector pili, a vestigial trait, contract in response to the stress such as cold weather and make the hair on our body stand up, forming bumps on our skin — arrector pili provided our mammalian ancestors with insulation as the hair on their bodies became erect and trapped air in them, and as a scare tactic to avoid being eaten (i.e. a porcupine); Cutaneous vasocontraction is the narrowing of blood vessels on the surface of skin that allows bodies to retain more heat as the skin acts as an insulator between outside stimuli and vital organs — the brain and heart — delivering more oxygen to them.

Facultative: The Inuit have a diet high in fats and calories, greatly increases their basal metabolic rate, which, in turn, allows one to produce more body heat as they burn the food they digest. Furthermore, this allows them to handle the gluconeogenesis process better (turning protein and fats into usable glucose); making their livers larger and increasing their volume of urine to digest what they eat better. On the other hand, the Ju/'hoansi of Southwestern Africa and the Aborigines of Australia — which live in environments that rarely face temperatures that stay below freezing for long and do not have diets high in fats — respond distinctly different physiologically to the cold: they develop thick fat insulation around their vital organs of the chest and abdomen; and long-term changes in their blood flow — vasoconstriction  — to retain heat. However, if they lived in an environment that stayed below freezing for long periods, they would suffer from frostbite and gangrene.

Developmental: People who live in colder climates are usually genetically shorter with high body mass and short appendages, which help produce and retain more heat than anyone who is taller with low body mass and long appendages. This was observed by Carl Bergmann, a German biologist in 1847, and Joel Allen, an American biologist in 1877. Carl Bergmann observed a negative correlation between body mass and environmental climate, and body shape/height (surface area) in relation to the rate of heat loss – coined Bergmann’s rule. On the other hand, Joel Allen noted a correlation between the length of appendages (more surface area) and rate of heat loss — coined Allen’s rule.

Cultural: Clothing, houses, diets high in fat, fire, and technology (heaters) are all cultural adaptations that allow us to keep warm in cold climates. The Inuit would build specialized homes out of tightly packed snow bricks that prevented the cold wind from entering, keeping warm air in and allowing them to build fires inside. Moreover, they made clothes and boots out of animal hide; to keep warm they would put the animal hide on the floor and huddle up together. Their diets — which were high in protein and fat — also allowed them to retain more body heat due to their increase in body mass. The Indians of Tierra del Fuego had similar cultures to that of the Inuit — which lived in the southern hemisphere while the Inuit were in the northern end.  




3. What are the benefits of studying human variation from this perspective across environmental clines? Can information from explorations like this be useful to help us in any way? Offer one example of how this information can be used in a productive way.

Studying human variation across environmental clines allow us to acquire knowledge in how our bodies react and adapt physiologically to climate and altitudes over short periods to long periods of time. It also allows us to study the phenotypic expressions and cultural adaptations in relation to the environment (i.e. skin color, height, diet and homes). Furthermore, with this information we have been able to create technology that has helped us withstand and acclimatize to different sets of conditions. For example, when someone is about to climb a mountain such as Mount Everest, they need to bring the proper equipment and clothing for it. Before climbing, they must acclimatize at separate camps on the mountain by ascending to high altitudes during the day and returning to a lower altitude to rest. To make the acclimatization process easier, they also increase their carbohydrates intake and lessen their protein and fats intake, drink around 1 gallon of water per day to help flush the kidneys of bicarbonate from an increase in respiratory rate, and use bottled oxygen tanks to compensate for the minimal oxygen. 4. How would you use race to understand the variation of the adaptations you listed in #2? Explain why the study of environmental influences on adaptations is a better way to understand human variation than by the use of race.  

Race is socially constructed and, therefore, can not be used to understand genetic adaptations; if it did, every separate race would look almost identical to each other. By studying environmental influences, we are able to see how they influence our appearance. For instance, although the Inuit live in latitude with fewer UV rays than at the equator, most retain a medium to dark skin pigment. Some of our dark-skinned ancestors — as they migrated into Europe and Asia, exposing themselves to different levels of UV rays — weren’t able to absorb enough sunlight to produce vitamin D, which played against them. Through natural selection, they started to adapt and populations with less melanin were created. However, the Inuit’s diet has consisted primarily of fish — which are high in vitamin D; this has allowed them to not depend on the sun for vitamin D production, retaining a high level of melanin. Although, their skin color can also be explained by how long they have lived in their environment — which has not been long enough for them to adapt less melanin — and by simply acknowledging that their were dark-skinned. Everyone, from different races and latitudes, develops different adaptations according to their genes and environment, not by racial terms. Thereby, we can not use this subjective social system to study biological variation.

Essential Factors of Communication

     Communication is a vital element that has played an important role in the survival and evolution of species, most importantly Homo sapiens. Communication is the way by which one conveys a message. Archaic hominids most likely began to communicate by the use of body language and grunts; eventually leading to the formations of language. Scientists do not know when language arose, but many hypotheses and theories have speculated on its origin. In the following experiments, we will explore the problems and advantages that arise when essential factors of communication and language are excluded.

     Experiment #1 only allowed me to communicate through hand gestures, facial gestures and body movements; no symbolic language whatsoever. This hindered my ability to convey complex and abstract concepts; attempting proved to be a difficult endeavor. I was left with basic concepts and words such as—but not limited to—no, yes, I do not know, time, the past, numbers, weather, and feelings. This was very frustrating to say the least; it left me feeling helpless in a way similar to a baby trying to communicate. I had my cousin(A) and a friend of hers(B) take part in this. They felt that it was difficult trying to figure out what I was trying to say at times—B said that I’m not very good at communicating through hand gestures although A disagreed and proved to understand me more times. Due to this, they overcompensated by asking lots of questions—primarily B.

     Participant B was more in control of the conversation than A or me; also initiating and changing topics. B asked me questions that mostly needed elaborate explanations, but I tried to respond to the best I could—it felt like an interview. There were times when I was excluded from the conversation, not because the participants did not care what I thought, more like they didn’t realize I even wanted to say something. When that happened, I did not attempt to get their attention to communicate my message because I figured I would not be able to convey it and even if I attempted to, it would not have been in a timely manner—dragging on and losing the enthusiasm. If this were to have gone on for longer, I would probably suffer from learned helplessness. Learned helplessness occurs when someone feels they have no control over a situation and do not persevere for reasons such as “what’s the point?” That feels depressing to say the least, but I am glad to have experienced this as it lets me empathize in particular  with people that have communication disabilities. Due to this, participants B and A had the power in the conversation throughout the 15 minutes and not once was I in power.

     In a culture where one is able to use spoken language and another is not, the one that is able to use spoken language would have the huge advantage of communicating complex ideas over the other. There would be more efficient and faster communication between the population in that culture and if in any danger, would be able to avoid it better. The speaking culture would probably feel they are superior to the other, and evidently oppress that culture. This can be observed many times when traveling to foreign countries. Native people may at times see foreign people as inferior and vice versa due to them not knowing a particular language. They associate this with not being intelligent which is preposterous. Those with language impairments, such as aphasia, are another example of people who are oppressed due to them not being seen as competent

     Experiment #2 was even more difficult that the first one. I was not able to express emotion through any means whatsoever, only to use my monotone voice. I struggled as soon as the questions from the participants began, not being able to hold in my laughter at how odd it felt and catching myself expressing minimal cues of emotion through facial movements such as wrinkling my brows as I concentrated and fidgeting my fingers to cope with the uncomfortableness—I was not able to go without fidgeting my fingers, it was impossible! At first, A thought that it would be better if they were to communicate as I was to make me feel more comfortable, but that was a bit more uncomfortable and weird and I could not take it.

     Due to my incompetence, the participants failed to continue the conversation. It was not until around the 5th try, after the participants and I had settled down, that I was able to keep myself under control. A did not participate in the conversation this time, while B did, but was not really engaged. It was evident the participants were bored with the conversation and did not want to continue the conversation.

     Emotion is shown and emphasized through body language; it is a vital part of communication and with it, we are able to understand better how someone feels. Some people on the autism spectrum struggle in reading the subtleties of nonverbal language and may leave them misinterpreting what is being said. Another faction that struggles with nonverbal communication is those with Amimia. Someone dealing with Amimia cannot comprehend hand gestures, even if previously understood.

     Our eyes tell us a lot about what is going on in our minds. For instance, closing our eyes for longer than a blink is our way of not letting our brain process anything threatening or undesirable. Another example is eye contact; when someone is lying, they usually look away to avoid eye contact. This poses a problem, at times, in police interrogations where suspects who know about these nonverbal cues deliberately make longer eye contact to throw the investigator off. However, investigators have learned to observe other nonverbal cues, such as intonation, that is indicative of deception and to watch when normal eye contact becomes abnormal. Eye contact can also show love, hate, confidence, creepiness, or enthusiasm. Furthermore, posture can indicate whether we are tense, relaxed, interested, angry, or disgusted. Our posture can emphasize what our face/eyes are trying to convey, such as leaning forward to show interest and pulling back to show disgust or fright.

     Through nonverbal language, we are also able to pick up on the cues of deception, honesty, or love that serve more as an adaptive benefit. Eye contact is important in showing confidence—as well as posture— and in seeing if someone loves or hates us. This allows us to fend for ourselves more efficiently—by spotting danger—, obtain resources—if you are confident you will excel more and people will believe in you—, and reproduce successfully—with cues of interest and trust. Body language is distinctly different throughout each culture and should not be seen as universal. For example, eye contact is seen as a sign of respects in some cultures, while in others averting your eyes is. Some signs are different in other countries—a thumbs-up is seen as vulgar in Iran and pointing with the wrong finger, or anything other than your whole hand, can be offensive in many countries. However, facial expression is probably the only nonverbal communication seen as universal. It was Charles Darwin who has been noted to be the first to discern facial expression as universal in his book The Expression and Emotion in Man and Animals.

     These experiments were insightful and interesting, but at the same time amusing. It would be a good exercise to allow people to empathize with those that have communication impairments. Moreover, it was startling just how much of body language contributes to our comprehension of communication. Without this ability to comprehend body language, we most likely would not have survived for long.