18.3.2 Artificial selection
Evidence of Evolution – One of Darwin’s most difficult tasks was to convince biologists that selection can produce change within a species.
He supported his argument by pointing out that farmers and breeders have developed many varieties of animals and plants through artificial selection. N addition Darwin himself bred pigeons and got variety in color, size, form and behavior (figure 18.4) through artificial selection which gave him a clue to the concept of artificial selection but he was unable to appreciate how this could operate in nature . Darwin used this observation to argue that species can change and that its characters are not fixed. He said if change is possible artificially, a similar process of change of selection can also occur in nature.
Fig 18.4 many types of pigeons produced by artificial selection.
Now a days biologists have produced completely new varieties of animals and plants by artificial selection. It is the process in which organisms with the ‘best’ or ‘desired’ traits/ characters are selected and bred with one another so that the traits/characters would be passed on to the offspring. Numerous varieties of animals (e.g., sheep, goats, cows, hens) have been produced by artificial selection to increase production of meat, milk, wool etc. similarly many plant varieties (fig. 18.5) for example cereals, fruits, vegetables etc. are produced for better quality in production and taste by artificial selection.
Evidence of Evolution
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Fig 18.5 many varieties of plants produced by artificial selection.