The environmental stress that I chose is high altitudes.
High altitudes disturb our homeostasis in several ways including:
- · Respiratory conditions (i.e. hyperventilation, and respiratory alkalosis)
- · Increase in Pulmonary Artery Disease (due to strain on the heart as it pumps harder in an effort to oxygenate the blood
- · Intense UV Radiation
Some additional long-term effects of living at high
altitudes vary based on gender and include the following:
- · Lower birth weight in infants
- · Delayed menstruation in women
- · Sterility in men
The major factor in the physiological changes resulting from
living at high altitudes has to do with the lack of oxygen available. The body
generally adapts to oxygenation levels at low altitudes and undergoes
significant changes when forced to adapt to abnormal levels. Some of the
complications that result from a severe lack of oxygen (known as hypoxia) include:
fatigue, dizziness, headaches, body pain, ear-ringing, swelling and blistering
of the hands and feet. More serious conditions include: swelling of the brain,
fluid build in the lungs, and in some cases heart attack and stroke.
In cases where the body is required to adapt to these
conditions in the short-term the changes it undergoes are not easy to detect
and happen internally. Some of these changes include increased breathing,
increased heart rates and blood pressure as the body attempts to compensate for
the lack of oxygen by increasing the breathing rate in an attempt to take in
more oxygen and by pumping more oxygenated blood through the body. Some of the
other changes include a suppression of certain body systems such as the
digestive system in order to conserve energy needed to increase production in
the circulatory system. Some of the more visible changes that might appear include
sleeping longer, dilated veins, fatigue, headaches, and in some cases repeat
hyperventilation.
As mentioned earlier some of the facultative changes include
the suppression of certain body systems as compensation for the increase in
function of the circulatory system which allows for more oxygenated blood to
circulate through the body. As the body becomes accustomed to the increased
function of certain systems it will become accustomed to utilizing other
systems such as the digestive systems at lower levels than individuals who live
at lower levels.
From a developmental standpoint the body actually changes
depending on gender. As mentioned earlier the reproductive systems of both
males and females are impacted. The average age for a female to start menstruating
is 13 in the U.S. In the Himalayas the average age is 17. Males can become
sterile at young ages making reproductive rates relatively low in comparison to
other areas. Women who do give birth run the risk of having children born with
low birth rates increasing the chances of infant mortality.
Culturally the high altitude lifestyle garners as level of
unity among its members and a relatively “calm” lifestyle in comparison to the
fast paced style of the U.S. For example Nepal is a fairly large society that
hosts a variety of people. Due to the increased level of UV exposure, almost
all Nepalese people have a darker pigmented skin color and dark hair color.
Both height and weight can vary but individuals who live at these altitudes generally
practice a diet that includes heavily spiced foods and lots of grains to help
with digestion. According to www.nepallink.com, about 80% of the populations are
Hindu and they adhere to the traditional practices of Hinduism which adds to
the feeling of togetherness among the people.
I think it’s important to study human variation across
environmental lines because it helps us to understand our differences from an
elemental level. It’s easy to look at someone and recognize the differences
between us but it’s another to actually look at what causes the differences
from an environmental and physiological stand point. For example when I began
researching the people in Nepal I was aware that there would be significant
differences between our lifestyles but I wasn’t aware of the challenges that
they face and the differences that their bodies undergo in order to sustain
itself in such high altitudes. It makes me have a better appreciation for people
who face those types of challenges as I recognize the difficulty that I would
have living in such an environment and it also makes me wonder about the
amazing ability that our bodies have to adapt in order to survive. It gives the
phrase “survival of the fittest” a whole new meaning. We can use this
information to gain a better appreciation of people from different backgrounds.
When we look at individuals living in these altitudes it’s pretty
easy to lump them into the same category of “race” because of the physical
similarities that I’d listed earlier. But I think that what makes people living
at high altitudes different is not specific to their “race” it has more to do
with the body functions that have contributed to their level of activity and as
a result; their way of life. In reality I don’t think “race” explains anything
from a developmental standpoint. In a sense, everything starts with how we are
made and the only way that we can really understand a person is by
understanding how our environment has shaped our development. You can’t tell
who a person is just by looking at them no matter how many people of the same
color or race you’ve seen. Everyone develops differently at some point, there
are different influences on each and every one of us all of our lives. Whether it’s
the area where we grew up, the type of home we grew up in, our family and friends,
socio-economic status, or the number of feet that we reside above sea-level, we
have to consider all of the factors of our development as we work towards
understanding each other. I think that as we expand our efforts towards
understanding each other from a less superficial level we have a better chance
at living together in relative peace.
Hi Whinira,
ReplyDeleteGreat post! very informative and interesting facts. It s interesting to learn how the environmental stress of high altitude really affects the body and how the body reacts to it and protects itself. Your pictures were nice too, they served as a perfect visual example for your explanation. I also think that its important to study human variation so that we can understand the environmental stress and how our bodies react to it. I also agree that its also more about understanding how the body functions and not really about race.
Great background on high altitude stress.
ReplyDeleteKeep in mind that adaptations are beneficial to the survival and reproductive success of an individual. So if a process works against that end result, in general, it is not an adaptation. This is complicated depending on the type of trait (short term, facultative, etc) but keep this in mind while reviewing the following comments:
Great discussion on short term adaptations.
With regard to facultative, you talk the suppression of some systems. This may be necessary in the short term, but it is not beneficial, especially for very long. This would be something that the body would have to do until other facultative traits kicked in.
An example of a facultative trait to hypoxia would be the generation of more red blood cells to allow for a higher concentration of oxygen delivery to the tissues.
Similarly, the processes you mention in the developmental section are not beneficial traits that help a human adapt to hypoxia. They are just a natural, physiological response (i.e., not genetic) to lower oxygen availability. Later onset of menses and males become sterile do not help with reproductive success.
Populations that have lived for many generations in higher altitude have evolved genetic traits that give their people higher baseline levels of hemoglobin and larger, barrel shaped thoracic cavities for larger lung capacities. These are traits they have from birth. They aren't acquired during their lifetime and they wouldn't lose them if they moved to a lower altitude environment.
I agree that populations at higher altitude will likely need to have adaptations to cold stress, but can you think of any cultural adaptations to hypoxia?
Good discussion in the section on the benefits of the adaptive approach. You used that magic word "cause"!
Great final discussion on race.
I like reading your blog. It was great and Everything was well written and informative. I learned how environmental stress of high altitude really affects the body and how the body reacts to it and protects itself. I liked how you started with a great background. and I also learned how our body reacts. It is very interesting blog. Great Job!
ReplyDeleteI liked reading your blog a lot I learned of things that I didn't know. I especially liked how interesting your pictures were they dragged you in and made you want to read more about what you were talking about. I also did not know that a long term affect could be sterile men and that your menstruation could be delayed. Great job with the information and work you put in.
ReplyDeleteHi Whinira,
ReplyDeleteI enjoyed reading your post. I did not realize that these connections were made with people who lived in high altitude. I knew that it made a difference in our breathing, but no idea that it might cause the swelling of the brain. The point you made about menstruation starting at 17 for females who live in high altitude, makes me think that there has got to be some sort of benefit to starting the menstruation cycle later rather than it just being a cause of the altitude. I agree with you we can not determine someone's life based on their race. Race is not a sign of developmental changes.