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

Explain starch, Starch It is a plant polysaccharide synthesized by  the...

Starch It is a plant polysaccharide synthesized by  the plant by photosynthesis and stored mainly  in  grains,  legumes,  roots  and  tubers.  Its molecular formula is (C 6 H 1

Mass extinction, Mas s Extinction - Since beginning many species ev...

Mas s Extinction - Since beginning many species evolved and got extinct (in fact only 1 % is living). Sometimes it occured suddenly at large scale, (most recently dinosa

What is dna sequencing, DNA sequencing is the process of reading the nucleo...

DNA sequencing is the process of reading the nucleotide bases in a DNA molecule. It includes any technology or method which is used to verify the order of the four bases- guanine,

Functions of insulin, FUNCTION S - (a) It is antagonistic to glucagon....

FUNCTION S - (a) It is antagonistic to glucagon. Insulin decreases the level of glucose in the blood. It acts by increasing the rate at which glucose is transported out of the

How are the beings of the phylum annelida classified, Q. Concerning the occ...

Q. Concerning the occurrence of separated sexes how are the beings of the phylum Annelida classified? These beings may be dioecious (the majority of polychaetes) or hermaphrodi

Necessity of transport in phloem, Necessity of Transport in Phloem Lea...

Necessity of Transport in Phloem Leaves produce photoassimilates and support various tissues including roots. The excess photoassimilates and metabolites stored in specialised

Fundamental polymers of life, The synthesis of the three fundamental polyme...

The synthesis of the three fundamental polymers of life, DNA, RNA and protein, is template-directed. This means that - Answer A. the monomers are assembled one by one in a sequence

Cyanotic heart disease, Cyanotic Heart Disease In  this there is a com...

Cyanotic Heart Disease In  this there is a communication between Pulmonary and systemic circulation through which venous blood enters the systemic circulatory system. The infa

What is the non-paralytic squnit, Concomitant or Non-Paralytic Squnit ...

Concomitant or Non-Paralytic Squnit This type of squint usually occurs when there is an obstacle in the sensory pathway of binocular reflex such as refractive errors, opacities

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