The Theory of Natural Selection

Topics: Black Death, Mutation, Bubonic plague Pages: 2 (702 words) Published: October 24, 2010
The bubonic plague, also known as the Black Death, was one of the deadliest pandemics in history. While mostly everyone who came into contact with the plague or another individual who was infected would soon become sick and eventually die for the deadly plague. But, there were a select few the didn’t become infected at all or became infected and then over came the sickness. How did some individuals live and most individuals die? This is because of natural selection. Natural selection is the process by which heritable traits the make it more likely for an organism to survive and successfully reproduce become more common in a population over successive generation. It is a key mechanism of evolution.

Individuals who were resistant to the bubonic plague were later found to have a rare mutated gene called Delta 32. This gene provides immunity to the deadly disease. People who are homozygous for the delta 32 gene are completely immune, while heterozygous have partial immunity. It is likely that this life-saving allele occurs as a random mutation and that it was selected for by the devastating black plague epidemics. The first wave of the plague hit Europe between 1347 and 1350, and it killed about one fourth of the population. Those few individuals who randomly inherited the delta 32 gene were favored by natural selection. The plague hit in waves over the next three generations and during these times there was an increase of the delta 32 gene found in the European population. What is the purpose of an emotion? Emotions can be happy and sad and everything in between. Some people have stable emotions that don’t fluctuate very much and other people’s emotions can go from extremely happy to extremely depressed in a matter of minutes. Sadness and depression are two emotions that most people would think that the human species could do without. These two emotions have developed through natural selection for a specific purpose. Sadness is easier...
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