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Evolution

Evolution. Mrs. Rago Bio. Charles Darwin. English scientist who developed theory of evolution Studied species on the Galapagos Islands Observed the species to compare features from each. Natural Selection. Mechanism for change in populations

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Evolution

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  1. Evolution Mrs. Rago Bio

  2. Charles Darwin • English scientist who developed theory of evolution • Studied species on the Galapagos Islands • Observed the species to compare features from each

  3. Natural Selection • Mechanism for change in populations • Occurs when an organism with certain variations (characteristics) survive, reproduce, & pass on their variations to the next generation • These variations make the organism more likely to survive and reproduce

  4. Reproduction in Natural Selection • Favorable traits make individual more likely to survive & reproduce • Individuals with the best traits pass them on to their offspring

  5. Convergent Evolution • Process by which different species evolve similar traits • Different ancestors but species with similar traits that have evolved to deal with the problem

  6. Divergent evolution • Descendants of a single ancestor diversify into species that each fit different parts of the environment

  7. Coevolution • When 2 or more species have evolved adaptations to each other’s influence

  8. Artificial Selection • Breeding organisms to produce offspring with identical traits • Example: breeding pure bred dogs

  9. On the Origins of Species • Book by Charles Darwin • First book on evolution

  10. Structural Adaptations • Changes that have developed in an organism’s form over time • Example: thorns on some plants • Take a long time to occur • Millions of years

  11. Mimicry • Structural adaptation that allows one species to resemble another species • Useful for a harmless species to resemble a harmful species, so that predators avoid the harmless species

  12. King snake-non venomous Coral snake- venomous & deadly

  13. Camouflage • An adaptation that allows a species to blend into their surroundings and avoid predators

  14. Physiological adaptations • Occur much faster • Changes in an organisms metabolic processes • Example: resistance to penicillin, insects & weeds resistant to specific pesticides

  15. Evidence for Evolution • Fossil record • Shows evidence of evolution but it is incomplete

  16. Anatomy • Homologous structures • Similar structures that come from a common ancestor

  17. Analogous Structures • Similar structures that are similar because they are used for the same purpose

  18. Vestigial Structures • A body structure that has no function in a present-day organism but was probably useful to an ancestor • Example: wings of an ostrich

  19. Embryology • Embryo is the earliest stage of growth & development of both plants & animals

  20. Biochemistry • Evidence for evolution, shows similarities in DNA or RNA

  21. Atmosphere of Early Earth • Large meteor impacted earth • More comets hit earth and brought ice with them which along with gases from volcanoes produces the water we now find on earth

  22. Atmosphere of Early Earth • Very little free oxygen • Water vapor • Carbon • Nitrogen

  23. Evolution of photosynthesis • Archaebacteria • Do not require oxygen • First group to develop • Cyanobacteria • Produce oxygen from their chemical reactions • This changed earth’s atmosphere

  24. Early Earth • Very hot • Lots of volcanoes meteorites • Lots of gases • Humans would never have survived early earth

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