10 25-11
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    10 25-11 10 25-11 Presentation Transcript

    • EVOLUTION REVIEW
    • Quick Review….
      • What is adaptation?
      • What is natural selection?
      • What are the 5 steps of evolution?
      • What is convergent evolution and how does it relate to analogous structures?
      • What are the three structures discussed in comparative anatomy?
    • Natural Selection in Depth
      • SC.912.L.15.13 Describe the conditions required for natural selection, including: overproduction of offspring, inherited variation, and the struggle to survive, which result in differential reproductive success.
      • What is the difference between artificial and natural selection?
    • Artificial Selection
      • Cattle and Livestock
      • Ranchers usually only breed their best cattle…. Why?
    • Natural Selection
      • What is natural selection?
        • When an adaptation/characteristic allows one organism to survive and reproduce better than others
    • What’s required for natural selection?
      • REPRODUCTION!!!
      • Overproduction of offspring: Animals reproduce to create more offspring than will likely survive (ex. Insects, birds, mice, fish, frogs, etc. etc.)
      • Remember the term “population capacity”
    • Struggle to Survive
      • If resources were unlimited and there was no threat from predation, there would be less natural selection.
      • The struggle to survive results in one organism “besting” another in the competition for resources
        • That takes care of the “Survival of the Fittest”… but remember, natural selection is not just about survival…
    • Differential Reproductive Success
      • If one organism survives extremely well but never actually reproduces, its genes will never be passed down and cannot be selected for…
        • Evolutionary “fitness” is the ability of an organism to survive and reproduce… it’s all about passing on your genes…
    • Adaptations that aid in reproduction
      • The goal of reproduction is how you end up with sometimes unusual and frivolous looking adaptations….
    • Inherited Variation
      • There must be genetic variation in the population.
      • If there is no genetic variation, then the genes coding for certain traits will always be the same.
      • Genes are passed down from generation to generation, thus, we get heritable traits .
      • What are some traits/characteristics that are NOT heritable?
    • CFU
      • Why is important to have inherited, genetic variation?
      • What are some factors of life that contribute to the “struggle to survive”
      • Natural selection is an adaptation that helps a species survive and WHAT?!
      • Explain population capacity
      • Define being evolutionary fit
    • BIODIVERSITY
      • SC.912.L.15.3 Describe how biological diversity is increased by the origin of new species and how it is decreased by the natural process of extinction.
    • BIOLOGICAL DIVERSITY
      • First… what is it?
        • Biological diversity refers specifically to the variety of organisms within a given area
      • Next… why are we concerned with it?
        • One of the ways in which scientists evaluate the environmental health of a region
    • Reduction of Diversity
      • Reduction of diversity creates less opportunities for inherited variation
        • Why does that matter?
    • Biodiversity can be reduced by…
      • #1 Loss of Habitat (ex. Rainforest)
      • #2 Decrease in Range (ex. Western ranching)
      • #3 Introduction of non-native species (ex. Dodo Bird, Rats, Mongoose)
        • This usually happens by accident, such as stowaways in ship and aircraft cargo holds
        • Can be devastating
        • Management of this issue must be thoroughly thought through
      • The Dodo lived on the island Mauritius and was made extinct by invasive dogs, pigs, rats, etc. as well as some initial human hunting.
      • Mongoose were purposefully introduced to Hawaii to deal with the rat problem (also an invasive species)… but now, due to differences in their sleeping patterns, they both live there!
      • #4 Over hunting-fishing-poaching (ex. Passenger Pigeon, Tasmanian Tiger/Wolf)
    • Genetic Diversity
      • Loss of inherited variation
      • When a species on the brink of extinction is preserved, reduced genetic diversity within the species is a concern
        • Why?
      • Populations that survive extinction tend to be genetically uniform
    • The result…
      • Genetic uniformity is detrimental
        • If one individual is susceptible to disease all individuals are susceptible disease
        • If one individual has a weakness, they all have the same weakness
          • Easy to wipe out a whole population
      • High genetic variation means at least some individuals will survive changes or diseases and the species will avoid extinction
    • BIOLOGICAL DIVERSITY = STABILITY
      • As each species goes extinct, the system becomes more unstable.
      • Stable ecosystems are more flexible and can rebound from natural disturbances and disasters.
      • Unstable ecosystems are susceptible to total collapse! This would lead to mass extinctions!
    • Once its gone its gone forever
      • Mutations are the only things that increase genetic variation
      • Since that evolution takes millions of years it is pretty much safe to say that once genetic diversity is gone its lost forever
        • Chances are it will not come back the same
        • Why not?
    • So…. In Essence
      • When new species evolve, biodiversity is increased.
        • An increase in biodiversity leads to greater ecological stability
      • When a species goes extinct, biodiversity is decreased
        • A decrease in biodiversity leads to ecological INstability
    • Extinction
      • Extinction: What is it?
      • What’s the difference between threatened, endangered, and extinct?
        • Extinct: species that no longer exist
        • Endangered: species that are in immediate danger of becoming extinct
        • Threatened: species in danger of becoming endangered in the near future
    • WE CAN DO SOMETHING!
      • There is at least one issue that you and I can do something about preserving biological diversity…