Microevolution An allele is one of the two or more versions o | NEET_JEE_NCERT_TRICKS

Microevolution

An allele is one of the two or more versions of a mutation at a certain location on a chromosome that is typically known, it is a variant form of a specific gene. To simply put into other words, it is a physical trait that gets expressed in a population causing fine and indistinct changes. However, the immediate changes do not reflect predominantly on the progeny. It can also be defined in the context of the Hardy-Weinberg equilibrium – “the allele frequencies change if any of the criteria of Hardy-Weinberg equilibrium is not fulfilled”.
It is also important to note that microevolution can perhaps lead to speciation, serving as a raw material for the process of macroevolution which is caused due to accumulation of changes from the process of microevolution. Hence, it can be deduced that both microevolution and macroevolution follow similar procedures, the difference being the time scale. In terms of evolution, this change occurs in a shorter frame in comparison to macroevolution.
The change that microevolution entails can be attributed to the following processes – Natural and artificial selection, Mutation, Genetic drift and Gene flow
There is a stream in Biology known as Population genetics that renders a mathematical explanation for the learnings of microevolution while ecological genetics deals with the observation of the process in the wild.

Microevolution Examples

Some examples of microevolution through the process of natural selection are herbicide resistance, pesticide resistance, antibiotic resistance and so on. Few other generally noticeable evolutionary instances of microevolution are the bacterial strains incorporating the property of resistance to antibiotics.
Few other examples are as listed below:

Resistance to pesticides by whiteflies

Resistance to DDT by mosquitoes

HIV strains developing resistance to antiviral medicines

Gonorrheal bacteria strains developing resistance to penicillin

Causes of Microevolution

The change that occurs in the gene pool from one to another generation, the change in the allele frequencies are attributed to the 4 fundamental evolutionary forces –

Mutations – this is known as one of the most likely causes of variations causing new alleles. A mutation is as a result of viruses, erroneous replication, UV rays and some mutagenic chemicals

Genetic drift – observed in smaller populations where evolution is as a result of haphazard changes in the allele frequency in a population.

Gene flow – it is the transfer of genes when the alleles are physically moving in a population. It takes place when an individual migrates between populations. The process causes an increase in the genetic diversity of a population

Natural selection – it can be artificial or natural and takes hundreds and thousands of years to take place and cause remarkable changes

Sometimes, the cause for microevolution is also attributed to Nonrandom mating.

@Science_Wallah