Evolution
...origin of diseases, such as heart attacks, tuberculosis, myopia and cancer, has been one of the most mysterious, complex and controversial aspects in medicine. Darwin's evolutionary perspective on medicine, however, can help us understand the origin of diseases which can be a valuable input in the ultimate goal of medicine. Evolutionary explanation provides a better understanding of our bodies' malfunctioning, natural selection's inability to eliminate the genes that cause hereditary diseases and the causes of other infectious diseases. Natural selection for the most part is responsible for determining the existence of mild to lethal modern-day diseases. Since natural selection improves our chances of survival and reproductive success, modern-day diseases are perhaps associated with increased fitness.
Our immune system has been shaped over centuries to provide resistance to pathogens and ensure our survival. It is designed to attack, impair and label foreign particles, such as bacteria, dirt in the skin and cancerous cells. Most often after we recover from an infectious disease, our immune system becomes sensitive so that we have greater concentration of lymphocytes to destruct the pathogens that caused the particular disease later in life. However, our immune system is not perfect. It can sometimes fail to attack, expel or destroy lethal pathogens like tubercles bacterial cells, roundworms and other parasites while at other times, it attacks certain substances when it should not. Such mistakes increase the chances of our vulnerability to pathogens and contraction of deadly diseases.
We contract infectious diseases in an endless arms race against pathogens like bacteria and viruses. Both the host and the parasite evolve over time to be able to counteract each other's adaptations and ensure their survival and reproductive success. However, evolution does not...
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