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Chapter 9 Diseases And Human Evolution Summary

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Chapter 9 in Diseases and Human Evolution discusses tuberculosis in humans and cattle. The first thing that comes to mind when I think of tuberculosis is the visits to the veterinarian whenever we wanted to cross state lines with livestock from our farm. Though Arizona is considered a tuberculosis free state, New Mexico is not. Even though our livestock was coming out of a TB free state, we still were required to take our goats to the vet and have blood draws done. The chapter reminded me of the relevance of tuberculosis in society today, both in livestock and humans, and how it is still a disease we are struggling to control in some countries, even though it has been around for several thousand years. One evolutionary mechanism made itself very clear while reading the chapter: the mycobacteria that causes tuberculosis can live outside of a host cell because of its lipid capsule. Barnes said that it can survive without a host for …show more content…

This has happened a variety of times throughout evolutionary history, like with seals and sea otters. Based on the genetic research done, it is believed tuberculosis coevolved with ancient hominids. This coevolution would have allowed the mycobacteria to always develop new mechanisms to overcome our immune systems. This is a great explanation as to why tuberculosis is still an issue in human populations. We have not managed to eradicate the disease, and I think this coevolution is why. When a disease is evolving as a species is, it makes sense that we developed ways to harbor it without showing symptoms. Barnes said that if twenty people are exposed, five to ten people will contract it, but only one or two will show symptoms. From that, I take that the coevolution has allowed humans to handle exposure better than we do with other

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