Natural populations have variations. Organisms of a population have various genetic traits. Some of these genetic variations make the organisms better suited to the prevailing environmental conditions. These organisms are more likely to produce more progeny. Over generations, the frequency of the beneficial genetic traits increases in the population due to the higher reproductive success of the organisms with these genetic traits.
This process of differential fitness of organisms of a population where the organisms with adaptive genetic traits have survival and reproductive benefits is called natural selection.
Natural selection is a process where organisms that adapt very well in their environment survive , reproduce and transfer genes over generations successfully. The advantageous genes are passed on to offsprings over generations. This process leads to evolution.
