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

What is phagocytosis , Phagocytosis is the ingestion of huge particles ...

Phagocytosis is the ingestion of huge particles like as bacteria and cell debris by large endocytic vesicles called as phagosomes.   In order to be ingested the particle must first

Explain the vertical implant position, Vertical Implant Position: The i...

Vertical Implant Position: The implant can be submerged in the bone up till the level, where it is surface treated or further embedded till its shoulder, depending upon the sit

What is cuticle, What is Cuticle? The nonliving, and noncellular outer ...

What is Cuticle? The nonliving, and noncellular outer layer of an organism secreted by underlying epidermis. Cuticles are common in a range of animals including nematodes, anne

History of plant classification, Q. History of plant classification? Be...

Q. History of plant classification? Before Darwin's theory of evolution and publication of his epoch making work 'Origin of Species' in 1959 no outstanding basis for the classi

Explain research dietitians, Explain Research dietitians Research diet...

Explain Research dietitians Research dietitians work in the field of normal or therapeutic nutrition Research dietitians seek ways to improve the nutrition of both  healthy

What is the nitrogen cycle, What is the nitrogen cycle? The nitrogen cy...

What is the nitrogen cycle? The nitrogen cycle represents the circulation and recycling of the chemical element nitrogen in nature. The nitrogen cycle basically depends on t

Pathophysiology and medical mangement of acute renal failure, Pathophysiolo...

Pathophysiology of Acute Renal Failure It is usually reversible but the deviation of physiologic function can be extreme and mortality in pediatric age group remains high. Th

Explain thoracic, Thoracic (non-cardiac) Antibiotic prophylaxis is give...

Thoracic (non-cardiac) Antibiotic prophylaxis is given routinely in thoracic surgery, but sup- porting data are sparse. In one study, a single preoperative dose of cefazolin be

How is gas exchange done in flatworms, Q. How is gas exchange done in flatw...

Q. How is gas exchange done in flatworms? Platyhelminthes exchange gases exclusively by diffusion through their body surface. This is only possible because all cells are locali

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