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Evolution — BIOLOGY STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 ScienceBIOLOGYEvolution3 Marks
Question
How can Hardy-Weinberg equilibrium be affected? Explain giving three reasons.
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Answer

Any disturbance in Hardy-Weinberg's genetic equilibrium indicates an evolutionary change.

It is caused by one or more of the following:

  1. Gene migration/ Gene flow:
  • When a section of a population migrates to another population in another place, the gene frequencies change in both the populations.
  • When gene migration occurs a number of times, there is gene flow.
  1. Genetic drift: Due to some chance events, the allele frequency becomes so different that they become new species.
  2. Natural selection: It is a process in which heritable variations enabling better survival are made to reproduce and leave more progeny; hence, there is a change in the allele frequency.
  3. Genetic recombination: In sexually reproducing organisms, recombination of maternal and paternal alleles occurs during gametogenesis, it is a major cause of variation in the allele frequency

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