Natural selection of heterogeneous environments, Biology

While describing normalising selection it was said that in uniform environments selection limits the variability of populations and evolves a genetic homeostasis. The type of selection process that is in progress in heterogeneous environments is known as diversifying selection.

Diversifying selection is the converse of normalising selection. Let us assume that a population occupying a certain environment, has two or more groups of genotypes (AA, Aa and aa) and meets two or more sub-environments or habitats. Among the two or more genotypes, let us say that a rare genotype (aa) that is well adapted to its habitat will be promoted by selection and the frequency of that genotype will increase as long as the habitat is not fully occupied. But when the habitat is saturated, no further increase in the frequency of that genotype an be observed. It is quite likely that the excess population could spill over to another sub-environment. The genotype may not be completely adapted to the new habitat and it is here that diversifying selection plays a role so as to establish a population consisting different genotypes. The phenomenon where two or more genotypes for a given trait exkt in a population is called genetic polymorphism. The different sub-environments co'me to be occupied by different genotypes and such an occupation would be as complete and efficient as possible.

Posted Date: 4/6/2013 1:42:03 AM | Location : United States







Related Discussions:- Natural selection of heterogeneous environments, Assignment Help, Ask Question on Natural selection of heterogeneous environments, Get Answer, Expert's Help, Natural selection of heterogeneous environments Discussions

Write discussion on Natural selection of heterogeneous environments
Your posts are moderated
Related Questions
Inhibitor Proteins - Enzyme-activity Control One kind of inhibitor protein found in higher plants is an endopeptidase which degrades nitrate reductase thus causing irreversibl

differenciate between plasma and serum

Explain the Composition of Blood Agar? Infusion from beef heart - 500 gm Tryptose - 10.0 gm Sodium Chloride -  5.0 gm Agar - 15 gm Distilled water - 1000  ml pH

What are the genotypes and respective blood types of the ABO system? Since the alleles are IA, IB and i the possible genotypes are IAIA (blood type A), IAIB (blood type AB), IB

In an experiment, it was necessary that you determine the concentration of dsDNA by using a spectrophotometer. You used 6 microliters of your purified dsDNA, and the reading at OD=

What is the stage of cellular respiration during which carbon dioxide is liberated? In aerobic cellular respiration the release of carbon dioxide occurs in the transformation o

Food Spoilage Bacteria - Lactobacillus Different organisms of this group, also known as "lactic acid bacteria", have different properties but all of them produce lactic acid fro

Q. What is function of Gamaaminobutyric acid? GABA is the principal inhibitory transmitter in the brain. The concentration of GABA is up to 1000 times greater than that of oth

Explain Community dietitians Community dietitians or  nutritionists  may  counsel  individuals and  groups on  sound nutrition practices  to  prevent  disease, maintain  healt

Cake mix evaluation  Originally, cake mix formulations were very similar to bakery cakes and utilized standard "Hi-Ratio" cake oils; however, development of improved cake mixes