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प्रश्न
Name and define the three types of natural selection.
उत्तर
Three types of natural selection are :
1) Directional selection: It produces a regular change in a gene pool of a population in one direction in respect to one or some specific characteristics. It is a progressive selection.
2) Stabilising selection: This type of selection favours average or normal phenotypes and eliminates extreme variants. It occurs in a constant or unchanging environment and eliminates new mutations. It favours homozygosity.
3) Disruptive or diversifying selection: This type of selection acts to break up a previously homogenous population into several different adaptive norms. It favours individuals at both extremes of a distribution curve.
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संबंधित प्रश्न
What is "fitness of an individual" according to Darwin?
Answer each question in ‘One’ sentence only:
Identify which one of the following is a test cross.
Briefly discuss the Theory of Natural Selection as given by Darwin.
The more characteristics two species have in common ______
Which concept was not included in Charles Darwin’s theory of Natural Selection?
Which one of the following statement is correct?
Match List - I with List - II.
| List - I | List II | ||
| (a) | Adaptive radiation | (i) | Selection of resistant varieties due to excessive use of herbicides and pesticides |
| (b) | Convergent evolution | (ii) | Bones of forelimbs in Man and Whale |
| (c) | Divergent evolution | (iii) | Wings of Butterfly and Bird |
| (d) | Evolution by anthropo- genic action | (iv) | Darwin Finches |
Choose the correct answer from the options given below.
Write drawbacks of Darwin's theory
The famous book "The Origin of Species" was written by ______.
Mention four main postulates of Darwin's theory.
