Expression of variability, Biology

Assignment Help:

In the preceding section we emphasised the fact that cvolution or the continuous adaptations to the environment can take place only when pheiiotypes exhibit variability. In the absense of variability, the chances arc that existing living organisms would become extinct since with the change in the environment these organisms would die without leaving progeny. Fortunatcly in living systems mutations and recombinations generate the required variability. However, organisms often strive to arrive at populations which are more or less uniform. This is possible because selection process acts in such a way that a certain degree of uniformity of phenotype is imposed among individuals of n population. If an individual were to be vcry different in some way from thc rest of the population. he would be less well adapted to the environment as compared to other members of the population and therefore unable to compete successfully with them. However, in a continuously changing environment, a slight phenotypic variability should be maintained in a population. In a changing environment no phenotype remains optimally adapted for long. This is the precise reason why variability needs to be generated continuously in a population and used to develop adaptations in the way Darwin suggested. We shall look into the mechanisms that generate variability.


Related Discussions:- Expression of variability

Adaptive Radiations, Adaptive Radiations The organisms all the time te...

Adaptive Radiations The organisms all the time tend to establish harmony with their environment. This process, called adaptation, enables the organism to face the vagaries of

Is fecundation in mammals internal or external, Is fecundation in mammals i...

Is fecundation in mammals internal or external? Fecundation in mammals is internal, with copulation. In the contemporary world human technology is able to endorse artificial e

Describe pericardial rub and their characteristic, Describe Pericardial Rub...

Describe Pericardial Rub and their Characteristic ? Generation of sound: The sound is generated due to rubbing of visceral and parietal pericardial surfaces against each other

Adaptation, ADAP T A TIO N - Characters that make an organism to...

ADAP T A TIO N - Characters that make an organism to adjust well and suited to its way of life. Variation occur in living organism due to change in environment. Th

Explain irradiation, Explain Irradiation The physical process of expos...

Explain Irradiation The physical process of exposing an object, system, or a material to a high radiant energy for the sterilization or preservation.

Explain the differance between savanna and desert, Explain the differance b...

Explain the differance between savanna and desert? Savanna : Savanna is characterized by relatively low rainfall and pronounced dry seasons. This type of climate produces a b

Cardiac cycle, Cardiac Cycle Cardiac cycle has two phases-systole and...

Cardiac Cycle Cardiac cycle has two phases-systole and diastole. Ventricular systole and diastole occur as a result of depolarization and chamber volume and pressure. The di

Taxonomy, classification of grantia

classification of grantia

Self-pollination - types of pollination, Self-Pollination - Types of Pollin...

Self-Pollination - Types of Pollination Self-pollination refers to the transfer of pollen grains from the anther to the stigma of the same flower. In chasmogamous flowers the

Define prevention of idd - double fortified salt, Define prevention of idd ...

Define prevention of idd - Double Fortified salt? iron deficiency anaemia and iodine deficiency disorders often co-exist, the most effective approach to control these public he

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