Monday, January 30, 2017

Human Variation

1. The environmental stress of high altitudes doesn't have a major impact on the human population but it does has a negative impact on the disturbance on homeostasis. Specifically, humans that travel to high altitudes have to adjust to the lower pressure. The typical human body is use to the pressure at sea level, so when he reach a high altitude our body reacts to the lower oxygen levels making it difficult for the oxygen to enter our lungs and bloodstream. This results in something called hypoxia meaning we are depleted of oxygen resulting in numerous symptoms or sometimes death. Depending on your body, some may experience it at a higher altitude compared to others whom may experience only a couple miles up, like lowlanders. Another one is having to adjust to the rapid changes of temperature during the day and night.

2. Adaptions
Short term: An example would be an increase in lung capacity because lungs are able to undergo acclimatization to the higher altitudes. This leads to an increase in fitness of a human as it is short term and will only last a few days once returning to normal or lower altitudes. Many athletics undergo this process in order to increase their endurance as they are able to accumulate more oxygen in their lungs to go for longer distances.
 Image result for increase in lung capacity due to high altitudes
Facultative: An example for this would be the increase in the production of hemoglobin in the blood allowing the lungs to expand and to increase the amount of oxygen that is in the bloodstream. In the process of this is it able to increase the size of capillaries and arteries to allow the flow of oxygen.
 Image result for hemoglobin
Developmental: This is a trait that has been developed over time by natural selection of indigenous ancestors. They have been able to adapt to the stress by being able to breathe faster allowing for more oxygen to enter the body. For example, the EPAS1 gene with is the gene that allows the acclimatization to lower air pressure.
 Image result for high altitude people
Cultural: An example of this would be mountain climbers that climb to higher altitudes as a hobby and they have to be able to reach really high altitudes but not for a long period of time. They go through proper training and use oxygen tanks. This is also used by Olympic athletes as a training technique in order to increase their endurance.
Image result for mountain climbers everest
3.  The benefits of studying human variations with the environmental stresses is that your are able to prepare yourself for the stresses and what they may endure. With the study of this you are able to see how certain stresses can effect our body. An example of this would be, if you were to travel to higher altitude, you would need to be able to train yourself and be able to adjust your lung capacity such as mountain climbers.

4. I would use race to understand variation of the adaptions by location and where those groups are located. For example, you see different races in certain environmental conditions and other on a different condition. I think the study of environmental influences are better to understand variation rather than race because certain things like the color of our skin, or body weight, or how we dress is dependent on how the environmental conditions we live in are. For example. those with a darker skin tone are more implicated to a sunnier environment where there are more  UV rays coming in.

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1 comment:

  1. L RodriguezJanuary 31, 2017 at 10:55 AM

    Okay in the opening section, though I would have liked more detail on the "numerous symptoms". How does it negatively impact body? That was the point of this first section.

    An increase in lung capacity takes time and requires the turning on/off of genes to reshape the lung size. That defines a facultative trait, not a short-term one. Short term responses are immediate. An example would be an increase in pulse and respiration to draw more oxygen into the lungs and pump it throughout the body.

    Good discussion on the facultative trait, with the understanding that the enlargement of the lung capacity you discussed in the first paragraph would also be an example.

    The genes you mention for the developmental trait increase the efficiency of oxygen transport. It doesn't increase respiration, which is actually a short term adaptation. An increase in respiration is an inefficient response to high altitude stress and won't be good for a human over the long term.

    I agree with the cultural adaptation of the oxygen tanks, which is the use of cultural tools to help adapt to a high altitude environment. "Training" is just helping your body adapt more quickly and more efficiently. It is really just working with the body's existing adaptations, not substituting a cultural tool in place of those adaptations.

    I don't disagree that more information and knowledge is beneficial personally, but how do we actually use this information in a productive way to benefit society? Can the information we gain from these types of studies have medical or scientific implications? Help people with lung diseases, such as cystic fibrosis? Can we develop more tools and techniques to help humans adapt to high altitude environments?

    I'm not sure how your explanation in the final section describes a way to use race to understand variation. All you are really doing is using race as it was meant to be used, to categorize humans into groups, not to explain the patters it produces.

    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.

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