What is a Natural Selection? Natural Selection is the process by which favorable inheritable traits become more common in successive generations of a population of reproducing organinsms and unfavorable heritable traits become less common. It is also known by its more commonly used, "the survival of the fittest". The three major components of natural selection are genetic variation, overproduction of offspring and struggle for exsistance. Each of these components contributes to the idea of natural selection because they all examine the different aspects as to why certain organisms are more likely to live based on certain favorable traits. Natural selection was an idea that originally came from Charles Darwin. He traveled the world making discoveries and he eventually used his findings to come up with his own theory called Darwin's Theory of Evolution. He was influenced by the works of other individuals and used their ideas along with his own to develope one of the most accepted theories used and taught today.
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Genetic Variation
Genetic variation is the genetic diversity of humans and represents the total amount of genetic characteristics observed within the human species. The two main sources of genetic variation are mutations and genetic shuffling that results from sexual reproduction. It was first thuroughly observed by Charles Darwin when he went on a trip. This trip is known as the Voyage of the Beagle and on it he traveled to several places including the Galapagos Islands. Here he studied the beak sizes of many different birds. He found that some birds had different sized beaks and he assumed that their beak sizes differed based on eating habbits. This suggests that their beak shapes evolved and mutated to fit their preffered food. For example, suppose there was a bird that liked to eat nuts or foods with hard shells. Over time the gene that produced bigger beaks was passed down from generation to generation until all the birds with big beaks were known as a specific specie of bird. This scenario proves that genetic variation helps certain species of organisms become more likely to thrive and survive.
Overproduction of Offspring
Overproduction of offspring is when there are too many offsprings and too little resources which results in the inablilty of the offsprings to survive. This is a contributing factor in natural selection because this causes competition in the ability to find food and shelter in order to survive. This is where natural selection comes into play because basically, those who are better adapted are more likely to survive and reproduce. This means that organisms with characteritics that are not well suited to their enviroment causing them to have low levels of fitness either die or leave few offsprings. But indidviduals that are better suited to thier enviroment causing them to have high levels of fitness survive and reproduce more successfully. Overtime organisms with the beneficial traits are likely to survive while the others are likely to gradually die off. Thus, natural selection results in inherited characteristics of a population. These changes increase a specie's fitness in its enviroment.
Struggle for Exsistance
The struggle for exsistance means that members of each species compete regulary to obtain food, living space, and other necessities of life. Darwin's idea was influenced by Thomas Malthus who believed that if the human population continued to grow unchecked, sooner or later there would not be insufficient living spaceand food for everyone. Darwin also believed that in this struggle, predators that are faster or have a particular way of preying on other organisms, will be able to catch more prey. However, the prey who are faster, better disguised, or better protected can avoid getting caught. The struggle for exsistance was a vital part to all of Darwin's theories.
Descent With Modification
Darwin also said that over long amounts of time, natural selection produces organisms with different structures or live in different habitats. This is why species today look different form their ancestors. Each living species has changed and come from other species over time. This principle is known as descent with modification. Descent with modification insists that all living things are related to each other. If you pay attention o all the different organims, you will realize that they all share similar traits. This is known as common descent. The common descent principle also states that all living species whether they are alive or extinct, originated from common ancestors. This means a single tree of life connectts all living things together.
