Definition - What does Natural Selection mean?
Natural selection is one of the basic mechanisms of evolution. It is the differential reproduction and survival due to differences in the observable characteristics (phenotype) of an organism.
The main idea behind this mechanism is that some hereditary characteristics are better suited (or favorable) to the environment than other types of hereditary characteristics. Organisms with less favorable characteristics will be less successful at reproduction.
Through this process, the characteristics of a population changes over a number of generations, which can result into genetic variations. This process occurs in all forms of life, including plants and animals.
MaximumYield explains Natural Selection
Natural selection can be a complex subject to comprehend, but an example of natural selection explained with a population of beetles may help. Assume there are green and brown variants of a beetle. Suppose green beetles cannot camouflage themselves in the environment as well and therefore are eaten more frequently by crows than brown beetles that are better camouflaged. A smaller population of green beetles leads to fewer baby green beetles. The more advantageous trait of brown color allows the brown beetles to produce more offspring and become more common in the population.
This mechanism occurs in plants as well. For example, if there are two plants - one with thorns and one without thorns, and pests usually tend to feed on the latter, natural selection might lead to a increase in the number of the former.