Question

Definitions/short answer: Character displacement Use an example (real or hypothetical) to explain the difference between VA and Vo What is the meant by genetic distance and how does it relate to geographic distance in different types of organisms?

Answer 1

Character displacement ,Use an example (real or hypothetical) to explain difference between VA&VD:-

1. Character displacement is the phenomenon where differences among similar species whose distributions overlap geographically are accentuated in regions where the species distribution do not overlap.
2. Character displacement is a term used describe an evolutionary change that occurs when two similar species inhibit the same environment. Under such conditions, natural selection favors a divergence in the characters- morphology,ecology,behaviour, or physiology of the organisms.
3. Example-Two of the most notable examples are two species of Darwin's finches & the island dwelling Anolis lizards.
4. VA is fat-soluble vitamin found both in plants& animals. Animal sources are referred to as retinoids,while plants derived VA precursors are called carotenoids.Ex-It is found in eggs,butter,whole milk,meat &also green-yellow fruits &vegetables.VD is a nutrients found in some foods is needed for health & to maintain strong bones. VD found in cells throughout the body.
5. GENETIC DISTANCE &How does it related to geographic distance in different types of organisms:-Genetic distance is the term used to describe the number of differences or mutations between two sets of Y-chromosome DNA or mitochondrial DNA test results.
6. Genetic distance is a measure of the genetic divergence between species or between populations within a species,whether the distance measures time from common ancestor or degree of differentiation. A genetic distance of zero means that there are nl differences in the two results &there is an exact match.
7. A measure of genetic distance (D) based on the identity of genes between population is formulated. It is defined as D=-Iogel, where 'I' the normalized identity of genes between two population. This genetic distance measures the accumulated allele differences per locus.
8. It is linearly related to geographical distance or area in some migration models.Thus,if enough data are available, genetic distance between any pair of different types of organisms can be measured in terms of 'D'.This measure is applicable to any kind of organisms without regard to ploidy or mating scheme.
9. Equilibrium models of isolation by distance predict an increase in genetic differentiation with geographic distance
10. A close relationship is shown to exist between the correlation of geographic distance or genetic differentiation(as measured by Fst) & the geographic pattern of heterozygosity across population.