BSCI 106 Speciation Notes

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BSCI 106 Speciation Notes
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2015-11-16 09:38:58
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Speciation
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BSCI 106 speciation terms
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  1. Speciation Characteristics?
    • fast or slow
    • requires both isolation and differentiation
    • - the order of both varies, positive feedback loop, a lot different ways to create both
    • no set species definition
    • -fungi, prokaryotes, plants for example
    • secondary contact outcomes are important
    • not a theory
  2. Morphology reliability? example
    • - meal moth, fish at the bottom of the lake with little light
    • - whale fishes, once thought three separate species but actually larvae, male and female of one species
  3. biological species concept
    • most organisms
    • testable reproductive isolation hypotheses
    • no gene flow due to isolating barriers
  4. ecological species concept
    • a distinct group whose memebers share a distinct ecological niche, usually closely related and isolated from other such groups
    • - most organisms (not factoring sexual reproduction)
    • - how distinct a niche?convergent evolution?
    • -isolating barriers hinder gene flow
  5. at what point does speciation occur?
    no one knows for sure
  6. anagenesis
    species never splits, simply changes over time
  7. cladogenesis
    2 distinct species are created
  8. pubic versus head lice example
    • cladogenesis
    • pubic lice is specialized for a different environment, can be attributed to the rise of clothin (non-fur based)
  9. cavefish example
    • anagenesis
    • some have lost their eyes
    • no loss of fitness, actually helps because less expensive, more resources available for other function
    • NOT use it or lose it
  10. classic process of speciation
    • first population isolation
    • then differentiation by chance, good reason
    • no set order, reciprocal
  11. Secondary contact
    • two things that are potential species that lose their former isolation
    • Test: if there is less fitness of each species together than separately, we have two distinct species that should be apart
  12. Allopatric Speciation examples
    • panama canal-crayfish
    • galapagos- finches got lost, found new habitat
  13. What causes differentiation over time
    • isolation leads to different selective pressures, natural selection
    • genetic drift
    • founder effects?
    • sexual selective differentiation
  14. Generalist mutualist, example
    one bee will polenate many different flowers, not faithful to just one
  15. Specialist mutualist, example
    yuca moth will pollenate only yuca plant, white flower only attracts bats at night as to keep them faithful
  16. Cheating examples?
    • orchids- dress up as nectar producers
    • odor- some bees take orchid chemicals to make pheremone
    • flower- fakes as carrion to attract pollenating flies
  17. Pseudo copulation pollenation
    • bee is trying hard to have sex with flower since flower looks a lot like a female bee, thus attracting bee without using energy
    • -doesn't change because its better to risk being wrong than to miss oppurtunity
  18. copper loving monkey flower
    • different from regular monkey flower because it can handle metal poisons, looks slightly different
    • - where did isolation come from?
    • temporal- different mating seasons select for different sexual traits
    • - now will not mate with regular monkey flowers
    • (sympatric speciation)
  19. aneuploid
    the ploidy is abnormal but not a full set wrong
  20. incipient speciation
    close to speciation
  21. aphids example
    • feed on both pees and alfalfa
    • some are better at pees, some at alfalfa
    • aphids mate where they eat
    • increasingly more likely to mate with others with similiar tastes
  22. misconceptions
    • true definition- speciation is a natural consequence of population subdivision
    • - no goal, just math
    • - only goal is reinforcement
    • - some differentiation and isolation is adaptive (hybrid reduction, better environments)
    • - some just luck( mutations that don't go well together, drifting till lower hybrid fitness, change in female preference)
  23. slow or fast?
    • slow usually, fast with polyploidy, mutations
    • can make hypotheses
    • we can see everystep of process
    • -not always in the same species
  24. new species by hybridization example
    spartina- cordgrass
  25. Stickleback example
    • got into lakes and became isolated between lakes and ocean
    • -more adaptation of local conditions
    • secondary contact with marine species
    • - hybrids weak, distinct lake bottom and shallow water types
  26. shared errors example
    • pseudogenes- no longer functions as a genes
    • 60 percent of olfactory are pseudo because wasn't a big deal
    • share with gorrilla
  27. adaptive radiation
    • rapid speciation
    • -new habitats
    • -innovations
    • -new resources
  28. Cambrian Explosion
    • sudden appearance of majority of our animal phyla
    • - 40 million year period (compared to 100's of millions of years )
    • - climate changed rapidly
    • - increased oxygen
    • -therefore new genetic mechanisms selected for
    • -ex: teeth will speed up adaption in prey, vv
  29. History is important?
    • what if meteor that hit dinosaurs missed
    • genetic drift
  30. what shaped our tree of life?
    • adaptive radiation
    • - key innovations (vascular tissues expand range)
    • -extinctions
    • exaptation- new opportunities from given system
    • -good enough evolution
    • -contingency? dumb luck, drift, constraint of ancestry
  31. Tree of life example
    • higher hemoglobin and higher basal respiratory rate vs lowland competition
    • -both were relatively good enough
    • - fitness changes based on outside factors
    • - how we get to endpoint involves luck
  32. amino acids
    • only 5 bases= 20 base pairs
    • good enough before and too dangerous to change now (were not always necessary)
    • no reasons to exist, just not enough molecular mechanisms to accomodate complete uniqueness
    • certain key structures were identical across the board for all life
  33. 20 species example
    • most of what we names? all on one little branch
    • 20 percen t of all plants and animals are beetles
  34. early earth conditions that shaped life
    • - photosynthesis (anaerobic) 3.5 B
    • - cyanobacteria (aerobic) 2.7 B
    • - 2.4 B now enough oxgyen to create rust in iron, ocean iron begins to rust
  35. great oxidation event
    iron is greatly depleted oxgyen becomes more free ( 2 percent to 12 percent jump)
  36. cambrian explosion (oxygen)
    • nearly all iron depleted, major changes in life now
    • complex body forms
    • aerobic respiration is given advantage, toxic to anaerobs
    • new heart of food web
  37. plastids
    • green is chloroplast
    • 2 types of reciever molecules in the same process as green algaed and land plants
    • bacteria too
  38. Land plants advantages?
    • more light for photoysynthesis
    • sufficient ozone for uv filtration
    • inorganic nutrients are now available on land
    • no herbivores for a while
    • disease and competition severely over looked evolutionary forces during this oxgyen revolution
  39. major disadvantages?
    • conservation of water
    • nutrient transportation
    • gravity!
    • gamete dispersal is harder
    • vulnerability

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