EVOLUTION
SOURCES OF VARIATION IN A POPULATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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The environment only
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Inheritance only
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The environement and inheritance
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none of the above
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Detailed explanation-1: -So, the correct answer is ‘Mutations’
Detailed explanation-2: -Discontinuous variations are decided by a single gene or a small number of genes. The phenotypic appearances of them are generally not affected due to environmental factors. Discontinuous variation does not show a normal distribution.
Detailed explanation-3: -Genetic basis of discontinuous variation At the genetic level: Different genes have different effects on the phenotype. Different alleles at a single gene locus have a large effect on the phenotype. Remember diploid organisms will inherit two alleles of each gene, these alleles can be the same or different.
Detailed explanation-4: -These characteristics are usually controlled by alleles of one gene or a small number of genes, and are not strongly influenced by the environment. An example of discontinuous variation is blood type in humans. There are four categories (A, B, AB or O), and humans can only belong to one of these categories.
Detailed explanation-5: -Discontinuous variation refers to things like eye colour or blood group, which have a limited number of possible values. In other words, a person’s blood can be A, B, AB or O, but it can’t be anything in between.