2.5

• What does the term "descent with modification" refer to in evolutionary biology?

  It refers to how populations have changed over time from common ancestors to produce organismal diversity.
• What are the four mechanisms that produce change in populations from generation to generation?

  Artificial selection, natural selection, genetic drift, and mutation.
• What is genetic drift?

  It is the process by which allele frequencies fluctuate unpredictably from one generation to the next in a small population.
• What is the founder effect in genetic drift?

  It happens when few individuals are separated from a large population.
• What is the bottleneck effect in genetic drift?

  It happens when an environmental event drastically decreases the number of individuals in a population.
• What is gene flow?


  It is the change in genetic frequency due to the movement of fertile individuals and their gametes in and out of the population.
• How does natural selection function as a mechanism of evolution?

  It favors organisms whose traits are well-suited to the environment, allowing them to survive and produce more offspring.
• What is the only mechanism that results in adaptation?

  Natural selection.
• What is directional selection?

  It is when one of the phenotypic extremes is favored by natural selection, often occurring when an environment changes.
• What happens during disruptive selection?

  Both extreme phenotypes are favored, while organisms with intermediate phenotypes tend to underperform and may become extinct.
• What is stabilizing selection?

  It favors intermediate variants and reduces variation in a population, maintaining the status quo.
• What are the three mechanisms for evolutionary change?

  • Genetic drift
  • Gene flow
  • Natural selection
• How do the effects of genetic drift differ from those of natural selection?

  • Genetic drift: Random fluctuations in allele frequencies, especially in small populations.
  • Natural selection: Non-random process favoring traits that enhance survival and reproduction.