Natural Selection and Evolution Impact on Health Essay Example

Natural selection is when a population becomes adapted to an environment over time. Now this is not the same as evolution. Evolution is when there is a change in the genetic composition of a population over time. Evolution is also possible without natural selection via a process called genetic drift. In order for natural selection to occur there must be specific conditions met. First, there has to be fewer resources to support the organisms, or in the terms of humans, the individuals. The second condition is variation within the population must be present in order for natural selection to take place. The final condition for natural selection to happen is that the variation must be heritable.  

There are many examples of natural selection occurring in humans, but the most common example of would be the development of lactose intolerance. Lactose intolerance is when a human cannot digest the sugar lactose in milk because their body does not produce the lactase enzyme. This would be considered natural selection because this variation of not being able to produce the lactase enzyme is hereditable, which means it is passed to offspring. This example of natural selection is most commonly seen in adults. Due to this development of lactose intolerance more and more people have been turning to alternate sources of milk, like almond milk, coconut milk and lactose free milk, to get their daily doses of vitamins and minerals that they would get in regular dairy milk, but without the consequences of ingesting lactose.  

Another example of natural selection that affects humans is a bacteria's resistance to antibiotics. Because many antibiotics are used incorrectly, some bacteria, and even fungi, have become resistant to some antibiotics. Genetic variation is the main reason for bacteria to develop a resistance to antibiotics. It is because of this genetic variation in bacteria that an antibiotic may kill some but not all of the bacteria it was designed to kill. The ability for the bacteria to thrive and reproduce genetically superior copies of themselves is referred to as differential reproductive success. One example of a bacteria's resistance to an antibiotic is penicillin. Penicillin was first used in 1942, with the increase in its use over many years, most types of bacteria have developed a resistance to penicillin. This example of resistance in bacteria can be harmful to humans because without other antibiotics to treat these bacteria in the mid 20th century, many people died because of their infection or illness.  

This knowledge of natural selection and how they affect humans can be very beneficial for my future health. As of now I am not lactose intolerant, but because of natural selection it may happen when I am older. This knowledge of lactose intolerance in previous years has been beneficial to others because the world now has different alternatives to dairy milk for those who are lactose intolerant. Even though bacteria are always changing based off their environment, knowing about antibiotic resistance can help the world to adapt their antibiotics and make new ones based off of the genetically superior forms of bacteria.