BSCI 106 chapter 17 vocab

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BSCI 106 chapter 17 vocab
2015-11-03 20:19:44
chapter 17 vocab
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  1. species
    groups of organisms that mate with one another
  2. speciation
    the divergence of biological lineages and the emergence of reproductive isolation between lineages
  3. sepeices concepts
    what is a species? many different interpretations
  4. morphological species concept
    • made by Linnaeus
    • states that species are defined by groups of organisms that are similar to each other in appearance
  5. reproductive isolation
    • a state in which two groups of organisms are unable to exchange genes
    • each group now part of a "new branch on the tree of life"
  6. biological species concept
    • species are groups of actually or potentially interbreeding natural populations that are reproductively isolated from other such groups
    • does not include asexual organisms
  7. lineage species concept
    one species splits into two or more daughter species that are then separate entities
  8. lineage
    • ancestor -> descendant
    • over time
  9. allopatric speciation
    • allopatric - "other homeland"
    • the condition of speciation caused by a physical barrier
    • body of water, mountain range, or any land inhospitable to a group of organisms
  10. galapagos finches
    • an example of allopatric speciation
    • the finches crossed the sea and settled on an island to create an entirely new gene pool and lineage
  11. sister species
    species that are each others' closest relatives
  12. sympatric speciation
    • sympatric- "together with homeland"
    • speciation without a physical isolation
  13. How does sympatric speciation occur?
    • disruptive selection (micro-habitats get preference for mating)
    • host-plant specificity (apples vs. hawthornes)
  14. polyploidy
    • the duplication of sets of chromosomes within individuals
    • when an individual is tetraploid, it cannot mate within the normal population and is thus reproductively isolated to only other tetraploids
  15. autopolyploidy
    polyploidy in an individual with parents from the same species
  16. allopolyploidy
    polyploidy in an individual from parents that were different species
  17. reinforcement
    • this is when hybrid individuals are less fit than non-hybrid individuals and selection will not select for them
    • incomplete reproductive isolation
  18. pre-zygotic isolating mechanisms
    • hybridization is prevented altogether
    • examples
    • 1. mismatched genitalia
    • 2. different mating seasons
  19. post-zygotic isolating mechanisms
    • less fitness for hybrids
    • examples
    • 1. sterility
    • 2. developmental problems
  20. hybrid zones
    areas where species interbreed because reproductive isolation is incomplete
  21. centric fusion
    chromosomes switch long arms with short arms