LIFE SCIENCE

Detailed explanation-1: -Key points. Genetic drift is a mechanism of evolution in which allele frequencies of a population change over generations due to chance (sampling error).

Detailed explanation-2: -The three mechanisms that directly alter allele frequencies to bring about evolutionary change are natural selection, genetic drift, and gene flow.

Detailed explanation-3: -Genetic drift is an evolutionary change in allelic frequencies of a population as a matter of chance. It occurs in very small populations, but its effects are strong. It occurs due to an error in selecting the alleles for the next generation from the gene pool of the current generation.

Detailed explanation-4: -Natural selection, genetic drift, and gene flow are the mechanisms that cause changes in allele frequencies over time. When one or more of these forces are acting in a population, the population violates the Hardy-Weinberg assumptions, and evolution occurs.

Detailed explanation-5: -Genetic drift describes random fluctuations in the numbers of gene variants in a population. Genetic drift takes place when the occurrence of variant forms of a gene, called alleles, increases and decreases by chance over time. These variations in the presence of alleles are measured as changes in allele frequencies.