Isolating mechanism, Biology

Assignment Help:

In this section we are to discuss the means by which populations get separated or isolated from each other, first gain the status of'Sub-species and finally evolve mechanisms which prevent them from mating with local populations to be called as a distinct species. In ghort, we are to discuss the mechanisms that are responsible for keeping populations from the access of each other that in turn leads to,origin of new species. You are aware that local populations generally interbreed among themselves ' with only rare cases of outbreeding. Therefore, the genotypes of different populations of a single species may show differences in some or many loci. The resulting phenotypes could be classified into sub-species based on the differences in parts.

These subspecies because of their proximity to other populations tend to meet the other members with the result that a single generally intermediate and variable population is formed. This would result in the loss of the status of subspecies for the population. However, if a sub-species is isolated over a long period of time and the breeding with its relations is prevented, then by continuing to accumulate the genetic differences it may lose its ability to interbreed with the parental species. Under such circumstances, the sub-species gets elevated to the status of a species, satisfying Mayr's definition of a species. When two groups are geographically separated from each other, it is often difficult to determine whether they do not interbreed any more. In other words, could they be referred to as allopatric species? Once they move into the same territory, fail to interbreed and form intermediates, they may said to have passed the test of sympatry or they could be regarded as sympatric species. In many cases it has been noticed that once the species status has been established, selection tends to promote those characters which act as a deterrent for the formation of hybrids, since usually hybrid progeny have a reduced fitness.


Related Discussions:- Isolating mechanism

Explain the source of energy - growth of microorganism, Explain the Source ...

Explain the Source of Energy - Growth of Microorganism? Constant supply of energy is required to carry out cellular activities, like biosynthesis and degradation of macromolecu

Light - marine ecosystems, Light - Marine Ecosystems Light is a limiti...

Light - Marine Ecosystems Light is a limiting factor in the ocean as it contributes significantly to organic production and distribution of marine life. The ocean is divisible

What are some diseases caused by abnormal gh secretion, What are some disea...

What are some diseases caused by abnormal GH secretion by the hypophysis? In childhood deficient GH secretion might be lead to delayed growth and in severe cases to nanism (dwa

Cell, The scientist who described cells as “many little boxes” was

The scientist who described cells as “many little boxes” was

Mechanism of cleavage, Mechanism of Cleavage Such as the mitotic divi...

Mechanism of Cleavage Such as the mitotic division in any cell, cleavage is the result of two events: mitotic nuclear division (Karyokinesis) followed via cytoplasmic divisio

Refining of crude oil, The crude oil obtained from earth's crust is refined...

The crude oil obtained from earth's crust is refined by following steps. Step 1: separation of water Cottrell's process is used for separation of water. Crude oil is an emu

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd