CHAPTER 15 Summary

• From a genetic perspective, a population is identified by the particular collection of alleles in its gene pool.
• Genetic diversity, as reflected by the number of different alleles in a population’s gene pool, is important for the continued survival of populations, especially in the face of changing environments.
• Evolution is a change in allele frequencies in a population over time. Evolution can be adaptive or nonadaptive. Mutation, genetic drift, and gene flow are nonadaptive forms of evolution.
• The founder effect is a type of genetic drift in which a small number of individuals establishes a new population in a new location, with reduced genetic diversity as a possible result.
• The bottleneck effect is a type of genetic drift that occurs when the size of a population is reduced, often by a natural disaster, and the genetic diversity of the remaining population is reduced.
• Inbreeding of closely related individuals may occur in small, isolated populations, posing a threat to the health of a species.
• Gene flow is the movement of alleles between different populations of the same species, often resulting in increased genetic diversity of a population.
• Genetic diversity can be assessed by using DNA sequences to determine allele frequency.
• Hardy-Weinberg equilibrium describes the frequency of genotypes in a nonevolving population. The Hardy-Weinberg equation can be used to detect evolutionary change in a population.
• According to the biological species concept, a species is a population of individuals that can interbreed to produce fertile offspring.
• Speciation can occur when gene pools are separated, gene flow is restricted, and populations diverge genetically over time.

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  MORE TO EXPLORE

  • Munshi-South, J. (2012) TED Talk: Evolution in a big city http://ed.ted.com/lessons/evolution-in-a-big-city
  • School of Ants http://schoolofants.org/
  • Munshi-South, J. (2012) Urban landscape genetics: canopy cover predicts gene flow between white-footed mouse (Peromyscus leucopus) populations in New York City. Molecular Ecology. 21:1360–1378.
  • Munshi-South, J., and Kharchenko, K. (2010) Rapid, pervasive genetic differentiation of urban white-footed mouse (Peromyscus leucopus) populations in New York City. Molecular Ecology 19:4242–4254.
  • Menke, S. B., et al. (2010) Urban areas may serve as habitat and corridors for dry-adapted, heat tolerant species; an example from ants. Urban Ecosystems 13(2):135–163.
  • Dunn, R. R., et al. (2006) The pigeon paradox: dependence of global conservation on urban nature. Conservation Biology 20(6):1814–1816.