Question

How do natural selection, genetic variability, and differential reproduction combine to produce the process of ‘micro-evolution’?

Answer 1

Micro-evolution maybe defined as the evolution on a very small-scale and it basically refers to all those changes in the allele frequencies that occur within a single population. The two topmost relevant mechanisms of these evolutionary change are: (1)Natural Selection and (2)Genetic Drift. Natural selection commonly predominates in the large populations whereas the genetic variability/drift predominates in the smaller ones. The process of Natural Selection mainly leads to an evolutionary change within a population when some individuals having certain traits have both a higher survival rate and reproductive rate than the others and can pass on these inheritable genetic features to their offspring. Through the process of natural selection, evolution acts whereby the genetic and the reproductive qualities that prove to be advantageous to their survival still prevails into their future generations. The cumulative effects of the process of natural selection gives rise to certain populations that have evolved to properly succeed in specific environments. Natural selection basically operates by the differential reproductive success (fitness) of the individuals. In contrast to the process of natural selection, environmental or adaptive pressures does not drive the changes due to genetic drift. The effect of genetic variability or genetic drift is much larger in the smaller populations and smaller in the large populations.