Biology - Other

Is the Human Race Evolving or Devolving – Evolving



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"Is the Human Race Evolving or Devolving - Evolving"
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We are evolving as all things do in response to environmental pressures, now how much we are evolving has to do with whether you look at the human race as a whole or if you look at different sections of the human population.

If you are to look at first world countries, where disease is low and nutrition is good, and bountiful resources available (for the most part) well there simply isn't much pressure for humans to evolve to. The only evolution we may be doing is resistance to certain diseases like AIDS, and we seem to be getting taller (as a general rule-although this does not hold entirely true, short men are selected against). Also there is some evidence we select our partners based on MHC compatibility. Your MHC complex is a major genetic component of your immune system. If you have kids with someone whose MHC complex is different than yours then your offspring will inherit a genetic immune resistance to more diseases. So we actually select for partners that have a different MHC complex. We do this by smell (and this was proven by a unique set of papers from Sweden) which begs the question what are we really doing by using perfumes to cover our scent? In another paper I read on the topic, it was proved in isolated human populations that couples with similar MHC complexes had an increased risk of miscarriage.

If you look at third world countries, where disease is common and widespread and resources are scarce and competed for then there is a lot more evolution going on. You have humans evolving traits that help them survive and acquire the resources necessary to live and reproduce. You also have disease resistance evolving by such mechanisms as Sickle Cell anemia. Sickle Cell anemia is a genetic disorder that changes the shape of a red blood cell from a round donut to a sickle shape. The sickle shaped cell doesn't carry as much oxygen as the donut cell. If you carry two copies of the gene for sickle cell anemia then all your red blood cells are sickle shaped and you cannot get enough oxygen to the cells of the body and you die. If you have one normal copy of the gene and one sickle cell copy then you make some sickle cells and some round cells. This allows you to lead a pretty normal life (as long you don't change altitudes quickly or try to live on a mountain. The sickle cells in your blood also give you some immunity to Malaria. For some reason, the bacteria cannot inhabit the sickle cells. So this give you an advantage over someone with all normal red blood cells in regards to surviving Malaria.

Where a population lives and how they live determine what they will evolve to be, unfortunately for modern man we haven't evolve to live in the world we have created just yet.

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