Hey, maybe there is something to this whole “natural selection thing.” (Note: sarcasm) According to Case Western University anthropologist Dr. Cynthia Bell, women who have the ability to carry more oxygen in their blood have more than twice as many surviving children as women who cannot carry as much oxygen. This is apparently a very strong example of natural selection at work in the human species.
A group of Tibetan Women in the Himalayas
Women who carry a copy of a specific version of a gene (an allele) that encodes the production of high oxygen saturated hemoglobin, a protein that carries oxygen to muscle tissues for production of ATP (energy), have 125% more surviving children. The specific gene has not been identified, but it is being worked on.
So how does that work? Well, women with that genetic allele will survive better in the high altitude Himalaya Mountains where oxygen is thin. They then are able to pass on that allele to their children, who in turn, survive better in that environment than children without the allele. This is an example of natural selection, “the process by which organisms that are better suited to their environment than others produce more offspring. As a result of natural selection, the proportion of organisms in a species with characteristics that are adaptive to a given environment increases with each generation. Therefore, natural selection modifies the originally random variation of genetic traits in a species so that alleles that are beneficial for survival predominate, while alleles that are not beneficial decrease. Originally proposed by Charles Darwin, natural selection forms the basis of the process of evolution (http://dictionary.reference.com/browse/natural%20selection)” (just in case you were born in the deep south and never heard of this).
We humans love to think that we are not animals and therefore somehow above of the theory of natural selection. We are not. This is why people with genetic diseases do not survive to have children: their genes will not be passed on. This is just another example that we are all tethered to the boundaries of the natural world.