Chapter 17

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Chapter 17
2010-11-18 05:27:30

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  1. Define species.
    Group of organisms who can successfully interbree with one another in nature, but who don't successfully interbreed with members of other such groups.
  2. Define population.
    All the members of a species that live in a defined geographic region at a given time.
  3. Define phenotype.
    Any observable traits that an organism has, including its physical characteristics & behavior.
  4. Define genotype.
    Genetic makeup of any organism.
  5. Define alleles.
    Coloration genes
  6. What is the gene pool?
    All the alleles that exist in a population; The raw material that evolution works with.
  7. What is microevolution? Why is it micro?
    A change of allele frequencies in a population over a relatively short period of time. It's micro because evolution within a population is evolution at its smallest scale.
  8. What is macroevultion? Why is it macro?
    Evolution that results in the formation of new species or other large groupings of living things. It's macro because its large-scale patterns produced by microevolution that evenually become visible --- mammals from reptiles.
  9. What can affect evolution?
    • 1. Mutation
    • 2. Gene Flow
    • 3. Genetic Drift
    • 4. Sexual Selection
    • 5. Natural Selection
  10. What is gene flow? How does it occur? Give a short example.
    • The movement of genes from one population to another. it takes place through migration.
    • Ex: Migration of plants or animals
  11. The essential unit that evolves in nature is the __________, which can be defined as all the members of a __________ living in a defined geographic region at a given time.
    population; single species
  12. Genes come in variant forms called __________. A gene pool's defined as all the __________ that exist in a __________.
    alleles; alleles; population
  13. Microevolution is defined as _________ in __________ in a population over a relatively short period of time.
    change; allele frequencies
  14. What the agents of microevolution all have in comon is that each of them can __________ in a population.
    alter allele frequencies
  15. Genetic drift is a __________ alteration of __________ in a population that has its greatest effect on __________ populations.
    chance; alelle frequencies; small
  16. In sexual selection, differential reproductive success comes about because of differential success in obtaining __________.
    mating partners
  17. True or False: If an insect has 1,000 offspring, we can label it as "fit" in an evolutionary sense.
    False; Evolutionary fitness eists only in a relative sense; in a population, one organism's more or less fit tan another depending on whether it has more or fewer offspring than another. So, having 1 offspring or 1,000 does nothing to qulify an organism as fit or not.
  18. In stabilizing selection, forms that are __________ are favored over forms that are __________.
    intermediate; extreme
  19. We normally think of evolution working through directional selection, in which a character moves toward __________.
    one extreme
  20. What is polygenic?
    Continuously variable traits/characteristics