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

Will sedantary lifestyle increased risk for cad, Q. Will Sedantary Lifestyl...

Q. Will Sedantary Lifestyle increased risk for CAD? A sedantary life style is associated with increased risk for CAD. Sedentary persons have almost double the risk for CAD deat

Mitral valve repair-indications for surgery, Mitral Valve Repair :  When...

Mitral Valve Repair :  Whenever possible, the valve has to be repaired rather than replaced. Preoperative investigations and a TEE done on the operating table will help the surg

How do sponges try to protect themselves, Q. How do sponges try to protect ...

Q. How do sponges try to protect themselves against harm from the environment? Is that method rudimentary or efficient? Sponges can close their pores to avoid the entrance of w

Which of the vertebrate classes are warm-blooded, Which of the vertebrate c...

Which of the vertebrate classes (a) are 'warm-blooded', (b) reproduce by laying eggs?   (a) Birds and mammals are 'warm-blooded'. (b) Fish, Amphibia, Reptiles

Behavioural adjustments, Behavioural Adjustments When faced with a su...

Behavioural Adjustments When faced with a sudden temperature change, most animals make behavioural responses that enable them to avoid extreme or lethal conditions. Among the

Pathophysiology of chronic wasting disease, Q. Pathophysiology of Chronic w...

Q. Pathophysiology of Chronic wasting disease? We all know that heart attack i.e. myocardial infarction is not the beginning but a last stage representing acute clinical manife

Define functions of manganese, Define Functions of Manganese? Like othe...

Define Functions of Manganese? Like other micro minerals, Mn also functions in mammalian enzyme systems. It can function both as an integral part of metalloenzymes and as an en

Explain congenital syphilis, Congenital Syphilis  A positive serologica...

Congenital Syphilis  A positive serological test for syphilis in a newborn without stigmata of syphilis may be due either to passive transfer of maternal antibodies or to prena

Nature of stress - responses of plants to stress, Nature of Stress - Respon...

Nature of Stress - Responses of Plants to Stress As mentioned in the preceding section, stress can be considered as any deviation in environmental condition from optimal for t

hormones secreted by gonads, Hormones secreted by gonads: 1. Testis and...

Hormones secreted by gonads: 1. Testis and ovary are called gonads in the human body. 2. Apart from producing gametes, gonads also secrete hormones. Testis : Testis s

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