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Evidence for Evolution

S7L5 Students will examine the evolution of living organisms through inherited characteristics that promote survival of organisms and the survival of successive generations of their offspring. .

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Evidence for Evolution

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  1. S7L5 Students will examine the evolution of living organisms through inherited characteristics thatpromote survival of organisms and the survival of successive generations of their offspring. S7L5.a Explain how physical characteristics of organisms have changed over successive generations (e.g. Darwin’s finches and the peppered moths of Manchester). S7L5.b Describe ways in which species on earth have evolved due to natural selection. S7L5.c Explain how the fossil record found in sedimentary rock provides evidence for the long history of changing life forms. Meet Darwin

  2. Evidence for Evolution • In 1831 Charles Darwin traveled around the world. In the Galapagos Islands he observed a great variety of organisms like finches p.175, tortoises and iguanas.

  3. Who was Charles Darwin? • Darwin had begun to think that species could evolve over time. It became clear to Darwin that Earth was much older than anyone had imagined. • What Is a Species? A species is a group of organisms that can mate with one another to produce fertile offspring. A characteristic that helps an organism survive and reproduce in its environment is called an adaptation.

  4. 2. The evidence Darwin collected led him to theorize that living things change over time or evolve.

  5. 3. Current evidence for evolution:(6) and (5) • Fossil record. Oldest fossils buried deeper. Horses evolved from a dog sized animal 60mya

  6. B. Phylogeny – the evolutionary history tells which species evolved from other species or had common ancestors.

  7. 4. How do we know the phylogeny – the history of how different organisms evolved? Phylogeny is determined . . . • Similar body structures ` • Similar embryonic development • Similar DNA codes • Unnecessary body structures

  8. a. Similar Body Structures

  9. b. Embryonic Development Because so many species are so similar in their development, it may suggest a common ancestor.

  10. c. Similar DNA

  11. d. Vestigial structures Some species have structures that they do not need. For example, humans ~ appendix whales ~ tiny hip bones that whales do not need may have been inherited from their walking ancestors.

  12. 5. What is Natural Selection? Evolution occurs because of Natural Selection – organism that is better adapted lives longer and produces more offspring.

  13. Natural Selection is the mechanism behind evolution.

  14. Another way to say it . . . • Natural Selection ~ the critters that are better equipped for survival have a better chance of…(you tell me)?

  15. Natural selection works in the same way, only the winner lives, and the loser dies.

  16. Natural Selection • Big Five Facts ~ • Overproduction: This refers to the way many species produce waaaay more offspring than can possibly survive.

  17. 2. Variation (differences) exist among individuals in a species

  18. 3. Competition ~ individuals of a species compete for resources.

  19. 4. Selection : Individuals with advantageous variations are more likely to survive.

  20. And those individuals that survive reproduce and pass on those advantages through their genes.

  21. When that organism dies the less advantageous genes die with it

  22. The variations can be a result of heredity or mutations

  23. Darwin…did he act alone? • Well…he did but there was another dude acting alone at the same time…Alfred Russel (don’t call me Russell) Wallace. • Wallace was an admirer of Darwin and texted him to say that he figured out the whole natural selection thing. • And then Darwin was all like…oh no you didn’t  • Yes…he did! This slide from Hightower

  24. Venn Diagram • Compare natural selection to selective breeding (aka artificial selection)

  25. Ecology Review • ..\CRCT\Ecology Review.ppt

  26. Holt Review Games • Genetics..\..\..\McDougal and review game\Review Game\rg_L_4 genetics.html • ..\..\..\McDougal and review game\Review Game\rg_L_5 genetics.html • Evolution ..\..\..\McDougal and review game\Review Game\rg_L_6 evolutio.html

  27. Brain Pop • http://www.brainpop.com/

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