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

How phosphorus in blood is presented, How Phosphorus in Blood is presented?...

How Phosphorus in Blood is presented? Phosphorus in Blood is Present as: 1.  Inorganic phosphorus in the form of HPO 4 or H 2 PO 4 2.  Organic or ester phosphorus such

What is meant by the substrates of enzymatic reactions, Q. What is meant by...

Q. What is meant by the substrates of enzymatic reactions? The Substrates are reagent molecules upon which enzymes act. The enzyme has spatial binding sites for the attachmen

Craninal nerves, Craninal nerves: Cranial nerves take their origin f...

Craninal nerves: Cranial nerves take their origin from different areas of brain  Some of them are sensory, some are motor and a few are mixed nerves. There are 12 pair

Congenital aortic stenosis-types of aortic stenosis, Congenital Aortic Sten...

Congenital Aortic Stenosis :  The valve may be unicuspid, bicuspid or tricuspid. Rarely it is a dome shaped diaphragm. Uni commissural aortic stenosis produces significant sy

Natural selection and genetic drift, Tell me which statement belongs to eit...

Tell me which statement belongs to either natural selection, genetic drift, or gene flow Can you tell me if I am correct? -Consistently causes a population to become better adapted

How can we determine the status of brain function, How can we determine the...

How can we determine the status of brain function Neuropsychological assessment is the clinical practise of using tests and other behavioural evaluation instruments to determin

What is sex-influenced dominance, What is sex-influenced dominance? The...

What is sex-influenced dominance? The Sex-influenced dominance is the phenomenon in which the manifestation of a phenotype of a gene in heterozygosity depends on the sex of the

Procedures for diagnosis - electron microscopy, Direct demonstration of the...

Direct demonstration of the causative agent by electron microscopy (EM): Where facilities for electron microscopy are available and a viral disease is suspected, presence o

Diagnostic evaluation of leukemia, Diagnostic Evaluation   A  study of ...

Diagnostic Evaluation   A  study of complete blood count (CBC) and blood chemistry mainly uric acid levels, is necessary for dignostic evaluation.  Radiologic  studies  are

What is the characteristic of cardiac muscle, What are the characteristics ...

What are the characteristics of cardiac muscle that allow it to be highly resistant to fatifue?

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