Answer to Question #117348 in Evolution for Shania kumar

Question

Discuss the process of natural selection and evolution

Answer 1

The members of natural populations vary with respect to characteristics at all levels. They differ in their morphology, their microscopic structure, their chromosomes, the amino acid sequences of their proteins. The members of natural populations vary in their reproductive success: some individuals leave no offspring, others leave many more than average. Natural selection is a difference in survival or offspring production by individuals with different phenotypes. The measure of survival or reproductive output is called fitness. It is through natural selection and differences in fitness that adaptations spread and become established in a species. Natural selection can be directional, disruptive, or stabilizing, depending on the phenotype it favors. Natural selection can lead to the formation of new species in some instances. Natural selection can also drive convergent evolution, in which different lineages evolve similar features in response to common environmental pressures.

Evolution may occur as a result of natural selection. Natural selection does not necessarily give rise to evolution. Evolution by natural selection is a property of groups, not individuals. 

The theory of evolution by natural selection was proposed by Charles Darwin in his book “On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life”.