Ecology 3.5

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Ecology 3.5
2010-05-23 22:09:55
UK BIO Introductory Ecology

day 3.5
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  1. speciation
    the evolutionary process by which new biological species arise
  2. allopatric speciation
    • different places
    • isolated populations (geographically)
  3. sympatric speciation
    same place
  4. parapatric speciation
    adjacent populations with some overlap
  5. peripatric speciation
    one large population withsome small isolates at the perimeter
  6. Mayr's biological species concept
    "Species are groups of actually or potentially interbreeding populations, which are reporductively isolated from other such groups
  7. premating isolating mechanisms
    • prevents union of gametes -> zygote
    • 1. mates do not meet (seasonal or habitat isolation)
    • 2. mates meet but do not mate (ethological or behavioral isolation)
    • 3. mates meet but no sperm transfer (mechanical isolation)
    • * can have pre and post simultaneously
  8. post-mating isolating mechanisms
    • 1. sperm transfered but dies before fertilization
    • 2. zygote dies
    • 3. zygote produces an F1 adult that has reduced viability (survival)
    • 4. hybrid is viable, but partially or completely sterile (fecundity) or the F2 is deficient
    • *can have both pre and post simultaneosly
  9. cline
    the gradual change in certain characteristics exhibited by members of a series of adjacent populations of organisms of the same species
  10. In the Mimulus (monkeyflower) speciation study, what traits did Schemske and Bradshaw find to be attractive or repulsive to bee and hummingbird pollinators
    • Bees prefer large flowers and avoid flowers with carotenoids
    • Hummingbirds prefer large nectar loads
  11. neofunctionalization
    • one copy of a duplicate gene is under selection to retain its original function, and the other copy is free to evolve a new function
    • if this process occurs in regulatory genes, then this could lead to the evolution of new developmental pathways and new bauplans (blueprints)
    • *deleterious mutations are more common than beneficial)
  12. subfunctionalization
    • regulatory genes often have multiple functions (pleiotropy).
    • Gene AB -> Copy1 AB, and Copy2 AB
    • Copy1 loses function A and retains B, Copy2 unchanged
    • Copy2 loses function B and retains A (it has pressure to retain A and can afford to lose B)
  13. silverswords vs tarweeds
    • they are close relatives
    • two regulatory genes and 1 structural gene exist as single copies in the tarweeds, but as duplicate copies in the silverswords
  14. regulatory genes vs structural genes
    • regulatory genes evolved faster than structural genes in silverswords (suggesting the regulatory gene is controlling the macroevolution in silverswords)
    • regulatory genes evolved faster in silverswords than in tarweeds
    • (regulatory genes are "master control" genes; they tell other genes to talk or shut up)
  15. adaptive radiation
    rapid evolution and diversification of a lineage into a wide array of species (ex: almost all mammals in Austrialia are marsupials, very few placentals)
  16. nonsynonymous vs synonymous point mutations
    • non / s
    • high number means rapid evolution and vise versa