Blog #3 Explain what microevolution is? What are the three ways that variation occurs?

Microevolution is a change in gene frequency within a population over time. This change is due to four different processes: mutation, selection (natural and artificial), gene flow and genetic drift.
Population genetics is the branch of biology that provides the mathematical structure for the study of the process of microevolution. Ecological genetics concerns itself with observing microevolution in the wild. Typically, observable instances of evolution are examples of microevolution; for example, bacterial strains that have antibiotic resistance. Microevolution can be contrasted with macroevolution, which is the occurrence of large-scale changes in gene frequencies in a population over a geological time period (i.e. consisting of extended microevolution). The difference is largely one of approach. Microevolution is reductionist, but macroevolution is holistic. Each approach offers different insights into the evolution process. Macroevolution can be seen as the sum of long periods of microevolution, and thus the two are qualitatively identical while being quantitatively different. Mutations alter the order of bases in the nucleotides of DNA. Mutations are likely to be rare and most mutations are probably harmful, but in some instances the new alleles can be favored by natural selection. Independent assortment (recombination of chromosomes that occurs during sexual reproduction) and the Crossing over that happens during meiosis.