Genetic drift Knowledge-Based Download PDF

Questions

1. 1.

   When multiple isolated subpopulations are subjected to prolonged genetic drift in the absence of gene flow and mutation, how does this evolutionary force affect genetic diversity within and between the subpopulations?

   • A) It increases genetic variation within each subpopulation and decreases divergence between the subpopulations.
   • B) It maintains genetic variation within each subpopulation while eliminating divergence between the subpopulations.
   • C) It increases genetic variation within each subpopulation and increases divergence between the subpopulations.
   • D) It decreases genetic variation within each subpopulation and increases divergence between the subpopulations.
2. 2.

   Which of the following describes the fundamental distinction between genetic drift and natural selection regarding their effects on allele frequencies within a population?

   • A) Genetic drift alters allele frequencies through stochastic sampling events regardless of fitness, whereas natural selection alters frequencies based on differential reproductive success.
   • B) Genetic drift introduces novel beneficial alleles into the gene pool, whereas natural selection primarily removes neutral alleles from the population.
   • C) Genetic drift produces predictable, directional adaptations to the environment, whereas natural selection causes non-adaptive fluctuations in allele frequencies.
   • D) Genetic drift operates exclusively in infinitely large populations, whereas natural selection takes place only when populations experience severe numerical crashes.
3. 3.

   Which of the following scenarios best exemplifies genetic drift acting via the founder effect?

   • A) An epidemic kills most members of a prairie dog colony, leaving a small surviving group with altered allele frequencies.
   • B) Herbivorous insects with camouflaged coloration survive bird predation more effectively than brightly colored variants.
   • C) A small group of storm-blown seeds colonizes a remote volcanic island to establish a new population.
   • D) Pollen from a mainland pine forest is blown across a mountain range and fertilizes trees in an isolated valley.
4. 4.

   In a small, isolated population experiencing no mutation or gene flow, what is the most likely long-term evolutionary outcome of genetic drift acting on a neutral allele?

   • A) The allele frequency will stabilize at a stable intermediate value because of balancing forces.
   • B) The mutation rate will rise substantially to replace any alleles lost by chance.
   • C) The allele will eventually either reach complete fixation or be permanently lost from the population.
   • D) Natural selection will automatically intervene to restore the original ancestral frequency of the allele.
5. 5.

   Which of the following statements best characterizes genetic drift in population genetics?

   • A) It systematically increases the frequency of beneficial alleles through differential reproductive success.
   • B) It causes random fluctuations in allele frequencies that have a greater impact on small populations than on large ones.
   • C) It relies on the continuous migration of individuals between populations to homogenize their gene pools.
   • D) It occurs exclusively in infinitely large populations that satisfy all assumptions of Hardy-Weinberg equilibrium.