Why is a large population size vital for evolution?

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please and thank you.

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  • 1 decade ago
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    Small populations may experience drastic changes in alleles due to chance from one generation to the next (genetic drift), and there is a greater chance of non-random mating (e.g. inbreeding). This is less likely to occur in large populations, as well as extinctions.

    Addition: eucompboy is absolutely correct, by the way. Large-sized populations aren't vital for evolution - you can see some amazing examples of relatively small populations that have evolved. All I'm saying is that if a population is too small, then effects of genetic drift and inbreeding may become too detrimental for the population to evolve - e.g. the possible accumulation of deleterious recessive alleles.

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  • Anonymous
    1 decade ago

    It isn't, but thanks for asking. The main advantage of a large population is that there will be plenty of individual variants, so something like a plague disease may not wipe out the whole population.

    But, as you can see from semi-isolated islands and archipelagoes, such as the Galapagoes and Hawaii, very small populations evolve just fine -- and you'll see quicker speciation on them BECAUSE of the genetic drift factors. I mean, jeez, Hawaii has 700 species of fruit flies, and it's NOT because there was a large population. It's because of repeated "founder effect" genetic drift.

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