Un-Natural Selection: Human Evolution's Next Steps

URL: http://www.npr.org/templates/story/story.php?storyId=129638953

Date Published: September 6, 2010

Source: NPR

For billions of years, species have evolved by natural selection. This process takes millions of years. However, humans have been on earth for only tens of thousands of years, and we are altering the world so much that genetic evolution is unable to keep up with the pace. Instead of the environment controlling the humans species, humans are creating their own environments. 

For example, before humans developed a cure for malaria, people were dying throughout Africa. But through natural selection, the people who were able to develop a sickle-cell mutation were resistant against malaria. These people were then able to survive, and their offspring would have these malaria resistant traits too. With natural selection, the death rate of Africans would have decreased through a span of billions of years. But humans quickly made medicine that cured people with malaria. With this medicine, the people who were treated were able to survive. Natural selection didn't occur anymore because the medicine made it so that it didn't matter whether one had a sickle-cell mutation or not. After several years, malaria didn't have much impact on Africans because of the medicine. But there were still people with the sickle-cell mutation who survived before medicine intervened. Although this sickle-cell mutation is no longer useful, if a child inherits this mutation from both parents, it turns into a sickle-cell anemia. 

In order to overcome bad mutations, humans have developed medicine. We want a cure for everything, such as eyesight. For instance, if a hunter was nearsighted, he would die of starvation pretty quickly because he would be unable to see any animals in the distance. But now there are glasses to counter this nearsightedness. Also, there are contact lenses that make the human vision sharper without wearing glasses, 

Now, natural selection is very fast. What usually happens during the course of billions of years, happens in a course of several years nowadays. Nature isn't the only one that selects the genes, because humans are doing it too. 

This article relates to the current unit which consists of natural selection. Specific traits of an individual helps it survive in its environment more than others. Then these traits are passed on through billions of years. Darwin's finches showed that a particular finch's beak made it able to eat certain foods and survive. But this slow process of natural selection is sped up by humans, and nature is no longer the only force.