1.
High altitudes provide environmental stress such
as low humidity strong winds and lower air pressure. The wind cause rapid
dehydration and amplifies cold stress. While the low air pressure leads to hypoxia,
which is insufficient levels of oxygen in body tissue or oxygen deficiency.
2.
Short-term adaptations to the stress of high
altitudes include a breathing and heart rate increase of up double even while resting
resulting in an increase of blood pressure and pulse rate as the hearts pumps
harder to get more oxygen.
A facultative adaption to high altitude is
the process of acclimatization when a person born at a low elevation travels to
a high elevation within
one or two day’s increases in metabolic rate, respiration,
heart rate, and production of red blood cells (hemoglobin) occurs. The
hemoglobin in the red blood cells is responsible for transporting oxygen to organs
and tissues
High altitude born natives have the
developmental adaption of developmental acclimatization in which the natives
grow slower and mature later than those in lower elevations as well as being
more efficient at diffusing oxygen from blood to body tissues.
A cultural adaption of Tibetans and Nepalese
is the solution to breathe faster to inhale more oxygen and broaden arteries
and capillaries, which results in higher blood flow rate and greater amounts of
oxygen delivered to the muscles while having relatively normal hemoglobin
levels.
3.
The study of human variation and explorations
has lead to the discovery of mutations such as the one found in Tibetans EPAS1.
The study of mutations like EPAS1 can help in the creation of vaccines and
medications for issues like oxygen deficiency or reproduction problems such as
maternal death caused by preeclampsia.
4.
Race could be used as an example of the Tibetans
and the EPSA1 being passed on within the Tibetans that allowed them to adapt to
the higher altitudes while still having normal levels of hemoglobin. Environmental
influences better explains adaption’s in human variations because the adoptions
do not alter for certain races it stays the same throughout each one.
Good opening description of high altitude stress.
ReplyDeleteAccurate explanation of the short term stress.
You do see an increase in red blood cells and hemoglobin and also an increase in metabolism, but these are longer term adaptations that help step in to take the stress off of the heart and lungs, which are the front lines in short term adaptations to high altitude. When a person first enters a high altitude environment, as you have already described, the heart and respiration rates increase, but this puts high stress on the heart, in particular, and can't occur indefinitely. When red blood cells and the metabolism increase, this allows the heart to slow it's heart rate moderately.
For your developmental section: "the natives grow slower and mature later than those in lower elevations as well as being more efficient at diffusing oxygen from blood to body tissues."
How does growing more slowly and maturing later help with hypoxia? Are these adaptations or secondary indicators that the body is being impacted by hypoxia? How does the body become more efficient getting oxygen to the tissues? This should have been explained a little more fully.
Cultural adaptations are the use of tools in some say to adapt to an environmental stress. The adaptations you describe are biological, not cultural. An example of a cultural adaptation includes the use of oxygen tanks by mountain climbers.
Good explanation for the benefits of the adaptive approach.
" Race could be used as an example of the Tibetans and the EPSA1 being passed on within the Tibetans that allowed them to adapt to the higher altitudes while still having normal levels of hemoglobin."
But as soon as you mention "higher altitude" you are using the adaptive, environmental approach, not race. Is there any way at all to use race alone to understand human variation? It is okay to acknowledge that there is no useful way to use race.