evolution and cladistics

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evolution and cladistics
2014-04-16 13:23:34
evolution cladistics bio

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  1. evolution
    Changes in the hereditary characteristics of groups of organisms over the course of generations
  2. Charles Darwin
    naturalist on the HMS Beagle, published "Origin of Species"
  3. Evolution occurs only when
    there is a change in gene frequency within a population over time-these changes can be passed on to the next generation
  4. small scale evolution
    Changes in gene frequency in a population from one generation to the next
  5. large scale evolution
    descent of different species from a common ancestor over many generations
  6. natural selection
    Greater reproductive success among particular members of a species arising from genetically determined characteristics that confer an advantage in a particular environment
  7. mechanisms of evolutionary change
    natural selection, mutation, migration, genetic drift; can cause changes in the frequency of genes in populations
  8. Natural selection and genetic drift cannot operate unless
    there is genetic variation
  9. What are the sources of genetic variation?
    sex (exchange of genetic material) and mutation (change in DNA)
  10. species
    Groups of individuals with genetic material from the same pool, almost always incompatible with that of another gene pool; potentially interbreed to produce viable offspring
  11. A species is given a unique name, species that share a large number of characteristics are grouped into genera, genera are grouped into higher categories. This system is called
    the Linnean system
  12. phylogeny
    the evolutionary history of a particular group of organisms, or "family tree" that shows genetic linkages between ancestors and descendents
  13. cladistics
    traces the phylogeny of species by analyzing shared derived characteristics and grouping species in clades
  14. clade
    group of species descended from one ancestral species; group of organisms that are more closely related in comparison to other groups
  15. hierarchy (in describing clades)
    species belong to a clade which belongs to bigger clade and so on
  16. We determine relatedness/define members in the clade by looking at
    shared derived characteristics or evolutionary novelties or homologies. ex. vertebral column > jaw bones > 4 legged > amniotic egg > hair
  17. A clade as a whole is determined by
    primitive characteristics: characters shared by all members of the clades
  18. Homoplasy
    when organisms contain similar characteristics that were independently derived, not from a common ancestor; the result of convergent evolution. ex. sharks, dolphins, and ichthyosaurs
  19. cladogram
    visual reconstruction of evolutionary history