Parasite Evolution 1 Flashcards
Q: How can knowledge of evolutionary processes be used to predict the structure (FST) of parasite subpopulations?
A: By understanding factors like gene flow, mutation, and genetic drift, we can predict if a parasite population is likely to have high or low genetic differentiation (high FST means more differentiation).
Q: What are potential outcomes of parasite-host coevolution?
A: Outcomes can include genetic adaptations in both parasite and host, selective sweeps, frequency-dependent selection, and evolutionary changes in traits like infectivity and resistance.
Q: What is evolved avirulence, and when might it be advantageous or not?
A: Evolved avirulence occurs when a parasite becomes less harmful over time, which can increase its transmission potential. It is advantageous if it promotes longer host survival, but may not be if high virulence increases transmission opportunities (e.g., by intermediate hosts needing to be eaten).
Q: Define microevolution.
A: Microevolution refers to evolutionary changes below the species level, observable over a few generations.
Q: Define macroevolution.
A: Macroevolution is the study of large-scale evolutionary patterns at or above the species level, occurring over thousands to millions of years.
Q: What are the five major evolutionary processes driving microevolution?
A: Mutation, genetic drift, gene flow, natural selection, and nonrandom mating.
Q: What is a mutation, and how does it affect genetic diversity?
A: A mutation is a change in DNA that can introduce new genetic variants, increasing diversity within a population.
Q: Are mutations always beneficial?
A: No, mutations can be neutral, beneficial, or harmful, depending on the ecological context.
Q: What is genetic drift?
A: Genetic drift is the change in allele frequencies in a population due to random chance, often reducing genetic diversity.
Q: What is a population bottleneck?
A: A population bottleneck occurs when a large portion of a population is wiped out, leaving only a few individuals and drastically reducing genetic diversity.
Q: What is the founder effect?
A: The founder effect is the reduced genetic diversity that occurs when a new population is established by a small number of individuals from a larger population.
Q: What is gene flow?
A: Gene flow is the transfer of alleles between populations, often due to migration, which generally makes populations more genetically similar.
Q: What is natural selection?
A: Natural selection is the differential survival and reproduction of individuals due to heritable traits that increase their fitness.
Q: How does natural selection affect genetic variation?
A: Natural selection tends to reduce genetic variation by removing disadvantageous alleles.
Q: Describe three types of selection on quantitative traits.
A: Stabilizing selection preserves the average phenotype, directional selection favors extreme phenotypes in one direction, and disruptive selection favors extreme phenotypes in both directions.
