CBSE Class 10 Science 2020 · Paper 31/5/2 · Question 21
Define the following :
- (a)Speciation
- (b)Natural Selection
- (c)Genetic Drift
Answer
Speciation is the origin of a new species, natural selection favours the best-suited variations, and genetic drift is chance change in gene frequency.
(a) Speciation: the origin of a new species from an existing (pre-existing) species, whose members can no longer interbreed with the original population.
(b) Natural selection: nature selects the individuals with variations best suited to the environment; they survive and reproduce more (survival of the fittest), and the species evolves.
(c) Genetic drift: accidental (random) changes in the frequency of genes in a population, especially a small one, without any survival advantage.
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