Question

The selection coefficient is dependent on relative fitness, with s portraying the power of selection against every genotype comparative with the genotype with most elevated fitness. With directional selection the allele present in the high fitness homozygote will increment in frequency over various ages, at a rate reliant on s, and at last going to fixation. In any case, regarding a prior polymorphism (i.e., no requirement for mutations), there are two mechanisms of evolution that can lessen the power of selection (observed s < anticipated s). What are these two mechanisms and how might they diminish the power of selection?

Answer 1

1. Mutation
2. Natural selection

Both of these mechanisms bring in some changes in the genotype of the organism that makes is less or more to adapt and survive in a given environment.

These both can diminish the power of selection by bring in new alleles which might bring evolution in a species but the species could not adapt itself to it, like mutation can block some protein which might be required for basic metabolism and this brings a negative selection for the new allele due to which the evolution does not happen or if it does than work is being done to remove the mutation so that it does not spread in many generations.

Natural selection plays a role in changing certain alleles in a population that might adapt it to its changing environment. But sometimes the changes make the species more vulnerable due to which the species goes into backward selection in order to save itself.