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प्रश्न
Name and define the three types of natural selection.
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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
Write a short note based on the information known to you.
Darwin’s theory of natural selection.
Give the scientific name of the organism which is cited as the classical example of "natural selection".
Select the correct statement.
Which of the following sequences fits into the organic evolution theory proposed by Charles Darwin and Alfred Wallace?
Which one of the following statement is correct?
Theory of natural selection dwells on:
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.
Mention Darwin's observations made on finches during his visit of Galapagos Islands. Write the explanation given by Darwin on his observations.
The selective agent that was responsible for causing the change in peppered moth was ______.
The famous book "The Origin of Species" was written by ______.
