EVOLUTION
DARWIN’S THEORY OF NATURAL SELECTION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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It is necessary for natural selection.
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It exists in almost all populations.
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It is caused by mutations and sexual reproduction.
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All of the choices are correct.
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Detailed explanation-1: -Variations are essential for natural selection to occur. It exists in almost all populations. It is caused by mutations and erotic reproduction. Hence, all of the choices are correct.
Detailed explanation-2: -Variations occur only in sexual mode of reproduction.
Detailed explanation-3: -Only variations that confer an advantage to an individual organism will survive in a population.
Detailed explanation-4: -Which of the following statements is not true with respect to variation? c)Selection of variants by environmental factors forms the basis of evolutionary processes. Solution: Since only useful variation has a chance of surviving, statement a) is incorrect.
Detailed explanation-5: -Major causes of variation include mutations, gene flow, and sexual reproduction. DNA mutation causes genetic variation by altering the genes of individuals in a population. Gene flow leads to genetic variation as new individuals with different gene combinations migrate into a population.