Botany: Plant Evolution

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Botany: Plant Evolution
2012-03-23 20:47:48
botany evolution

basics on plant evolution, including vocab
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  1. Evolution
    species change over time; "descent with modification", genetic change in population.
  2. Characteristics of Natural Selection
    • -Variation in population's traits
    • -Hereditary traits
    • -More offspring produces than survive
    • -"fit" individuals are more likely to survive and reproduce.

    • Darwin and Wallace came up with it
    • it occurs at a POPULATION level
    • acts only on phenotype
  3. Artificial Selection
    • Also know as selective breeding.
    • Evolution created by humans
  4. Heritable
    Can be passed from parents to offspring. Does not include somatic changes as Lamark suggested.
  5. Fitness
    An organism's ability to survive in it's habitat
  6. Adaptation
    An evolutionary modification that improves an organism's chances of survival and reproductive success.
  7. Fossils
    • Remains/traces of organisms in layers of rock.
    • formed by slow decay under sediment
    • fossil record is biased
    • radioactive isotope dating is used to predict age.
  8. Comparative Anatomy
    comparison of the structural details of any given organ found in different organisms
  9. Homologous Feature
    similarities in related species because of a common ancestor. Same structure, could have different functions.

    Ex. Whale flipper and horse leg.
  10. Homoplastic Feature
    similarities that arise through convergent evolution. Same function, could be different function.

    Ex. Insect and bird wings.
  11. Evidence for Evolution
    • Fossils
    • comparative anatomy
    • biogeography
    • biochemistry and molecular biology
    • testing
  12. Biogeography
    the study of the geographic distribution of living organisms and fossils.

    Evidence of Evolution: areas that have been isolated for a long time have unique flora and fauna.
  13. Molecular Evidence
    • Amino acids in common proteins (ex cytochrome c)
    • sequence of nucleoties in DNA more similar in related species.
  14. Population
    a group of individuals of the same species living in one area.
  15. Gene Pool
    the total genes present/available in the population
  16. Allele Frequency
    the number of times an allele appear in a population
  17. Genotype Frequency
  18. Hardy-Weinberg Principle: Definition
    the matematical prediction that allele and genotype frequencies do not change from generation to generation in the abscence of microevolutionary processes.

    (p^2) + 2pq + (q^2) = 1
  19. Hardy-Weinberg Principle: Conditions
    • Random mating
    • No mutations
    • Large population
    • No migration
    • No natural selection
  20. 4 Agents of Evolutionary Change
    • Mutation
    • Genetic Drift
    • Gene flow
    • Natural Selection
  21. Mutation
    • must occur in gametes to be inherited.
    • Increases potential for adaptation.
    • increases variation
    • may be positive or negative
  22. Migration
    movement of individuals (animals) or pollen/seeds (plants) into or out of a population
  23. Gene Flow
    mating across populations provides access to more alleles.
  24. Genetic Drift
    • production of random evolutionary changes in small breeding populations
    • decreases genetic variation within the population.
    • Makes population more susceptible to extinction.
  25. Modes of Selection
    Directional, Stabilizing, and Disruptive

  26. Founder Effect
    genetic drift that results from a small population colonizing a new area.
  27. Bottleneck Effect
    Population becomes smaller, limiting the variation in the population.
  28. Biological Species Concept
    a species consists of one or more populations whose members interbreed in nature to produce fertile offspring.
  29. Speciation
    the differentiation of populations into two distinct species
  30. Allopatric Speciation
    • speciation that occurs when one population becomes geographically separated from the rest of the species.
    • clines on mountains.
  31. Sympatric Speciation
    when a population forms a new species within the same geographic region at it's parent species. In plants, it often involves polyploidy organisms.
  32. Extinction
    the elimination of a species
  33. Types of Extinction
    • Background extinction: occurs in response to gradual changes in the environment over long time periods.
    • Mass extinction: numerous species/genera/families go extinct at once in a relatively short time. Has occured 5-6 times in Earth's history.
    • Antropogenic Extinction: extinction caused by humans.
  34. Polyploidy
    the possession of more than two sets of chromosomes
  35. Allopolyploidy
    When polyploidy occurs along with sexual reproduction between individuals of two species. Creates polyploid offspring
  36. Polyplodization