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Evolution powerpoint

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  • 1. Evolution
    SC.912.L.15.1 Explain how the scientific theory of evolution is supported by the fossil record, comparative anatomy, comparative embryology, biogeography, molecular biology, and observed evolutionary change
  • 2. Darwin wasn’t the only one
    Lamarck
    Changes in a phenotype occur because of an environmental need
    Giraffe
    Modifications were passed onto the next generation
    Inheritence
    “need” was dictated by environmental change and that change involved movement towards perfection
  • 3. Now we know
    No evidence that changes in environment can initiate changes in organisms that can be passed on to future generations
    Change originates in the process of gamete formation
    Environment does not create these variations it determines the survival of these variations
  • 4. “Decent with Modification”
    Organic Evolution: “Decent with modification” - Charles Darwin
    Species change gradually through adaptation.
    Chance
    FLASH CARD ALERT
    ADAPTATION: A single individual has a random mutation/trait that creates a change in phenotype, which increases the organism’s chance of successful reproduction.
    Leads to: NATURAL SELECTION
  • 5. FLASH CARD ALERT: NATURAL SELECTION: The adapted individual is able to survive and reproduce in the new environment better than others
    Then: The adapted individual reproduces, creating more individuals with the same adaptations.
    These adaptations become predominant in the population, thus altering the genetic makeup of the entire population… OR…
    A new species arises that co-exists with the ancestor
  • 6. THE STEPS OF EVOLUTION
    1. Random mutation. A single individual has a random mutation/trait that is beneficial in its environment.
    2. Natural selection: The adapted individual is able to survive and reproduce in the new environment better than others
    • 3. Reproduction of adaptive trait: The adapted individual reproduces, creating more individuals with the same adaptations.
    • 7. 4. These adaptations become predominant in the population, thus altering the genetic makeup of the entire population… OR…
    • 8. 5. A new species arises that co-exists with the ancestor
  • Flightless Birds: Penguin
  • 9. Random Mutation:
    Can be advantageous (adaptation) neutral, or maladaptive
    Adaptation: characteristics that increase the potential of an organism to successfully reproduce in a specified environment
    Adaptations are characteristics that increase an individual's evolutionary fitness.
  • 10. FLASH CARD ALERT:
    EVOLUTIONARY FITNESS: measure of the capacity for successful reproduction in a given environment relative to others of that same species.
  • 11. Example: The Hedgehog
  • 12. How Natural Selection Works
    All organisms have a far greater reproductive potential than is ever realized
    Starfish
    Struggle of survival:
    Not enough resources to go around
    Changes in the environment: climate change, food shortages, environmental stressors.
    Inherited Variations exist
    Genetic mutation & recombination
  • 13. These genetic changes MAY BE an advantage
    Chance.
    Because individuals with maladaptive traits are less likely to reproduce the maladaptive traits become less frequent and are eventually eliminated

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