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Natural Selection

Natural Selection. Natural Selection:. A process by which characteristics that make an individual better suited to it's environment become more common in the species. Sometimes referred to as “survival of the fittest”. How Does Natural Selection work?.

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Natural Selection

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  1. Natural Selection

  2. Natural Selection: • A process by which characteristics that make an individual better suited to it's environment become more common in the species. • Sometimes referred to as “survival of the fittest”

  3. How Does Natural Selection work? Those with the unique characteristics best suited for their environment will survive and produce offspring. End result = ADAPTATIONS

  4. English Peppered Moth –Natural selection in action dark moth - random mutation not as common Soot covered tree England 1800’s camouflaged moth

  5. Adaptations • Behaviors or physical characteristics that allow organisms to live successfully in their environment Shell for protection Long neck to reach leaves Long shallow roots, needles to protect from animals

  6. Niche • An organisms’ role in an ecosystem = niche. • Niche and Habitat are different • Address of an organism = Habitat • “Job” or “Profession” = Niche Organism = tree Habitat = Forest Niche = produce oxygen provide home for birds

  7. Explain why two organisms cannot occupy the same niche: • If two species occupy the exact same niche in nature, one will die off due to competition for limited resources.

  8. Video Link – Niche, Competition, Predation, and Symbiosis http://www.youtube.com/watch?v=D1aRSeT-mQE

  9. Three major types of interactions among organisms: • Competition • Predation • Symbiosis

  10. Competition: • The struggle between organisms to survive as they attempt to use the same limited resources.

  11. Predation: • An interaction in which one organism kills another for food.

  12. Predator or Prey: • Predator - organism that does the killing • Prey – organism that is killed.

  13. Effect of predation on population size: • What variable is plotted on the x-axis? ______ • What two variables are plotted on the y-axis? ________ and __________ years # of moose # of wolves

  14. Effect of predation on population size: • How did the moose population change between 1965 and 1972 ___________ • How did the wolf population change between 1973 and 1976? __________ It increased It increased

  15. Effect of predation on population size: • How might the change in moose population have lead to the change in wolf population? • The wolf preys on the moose so more moose meant more food for the wolf.

  16. Effect of predation on population size: • How might disease in the wolf population one year affect the moose population the next year? • Disease in the wolf population might cause some to die. With less predators, the moose population would most likely increase.

  17. Examples of Predator Adaptations • Cheetah speed • Owl eyes • Jelly fish venom

  18. Defense Strategies of Prey • Mimicry • Protective Covering • False Coloring • Warning color • Camouflage

  19. Video Link on Predator and Prey Interactions http://www.youtube.com/watch?v=vZynrBA91fY

  20. Interactions – Three Types

  21. Symbiosis – a close relationship in nature that benefits at least one species Bacteria from gut of termite Termites

  22. Symbiosis

  23. Mutualism • Both species benefit

  24. Commensalism • One species benefits, but the other isn’t harmed or helped.

  25. Parasitism • One species benefits and the other is harmed. • The one benefiting is the parasite • The one being harmed is a host

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