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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I AND II
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I AND IV
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II AND IV
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III AND IV
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Detailed explanation-1: -The three main sources of genetic variation arising from sexual reproduction are: Crossing over (in prophase I) Random assortment of chromosomes (in metaphase I) Random fusion of gametes from different parents.
Detailed explanation-2: -Genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism’s offspring).
Detailed explanation-3: -Mutations and recombination are major sources of variation.
Detailed explanation-4: -Meiosis causes the reshuffling of the genes. This creates variations in the gametes of the parents.
Detailed explanation-5: -During meiosis, homologous chromosomes (1 from each parent) pair along their lengths. The chromosomes cross over at points called chiasma. At each chiasma, the chromosomes break and rejoin, trading some of their genes. This recombination results in genetic variation.