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Theory of Evolution

Theory of Evolution. Charles Darwin. 1831 - Sailed on HMS Beagle The voyage lasted 5 years Gathered evidence about species and how they change. Evidence. South America: Darwin found fossils of extinct armadillos that closely resembled the armadillos living in the area.

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Theory of Evolution

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  1. Theory of Evolution

  2. Charles Darwin • 1831 - Sailed on HMS Beagle • The voyage lasted 5 years • Gathered evidence about species and how they change

  3. Evidence • South America: Darwin found fossils of extinct armadillos that closely resembled the armadillos living in the area.

  4. A collection of Glyptodons -- giant armadillo-likefossilshttp://abcnews.go.com/Technology/Science/story?id=6815330&page=2

  5. Evidence • Galapagos Island and coast of South America had animals and plants that were similar to one another but also different in ways. • Darwin surmised that S.A. animals migrated and then changed (over time). • http://abcnews.go.com/Technology/Science/story?id=6815330&page=3

  6. Descent with Modification

  7. Evolution: • Descent with modification from a common ancestor. There must be a change in gene frequency OVER TIME. • Time is KEY

  8. Evolution??? • Beetles on a diet • Imagine a year or two of drought in which there are few plants that these beetles can eat. • All the beetles have the same chances of survival and reproduction, but because of food restrictions, the beetles in the population are a little smaller than the preceding generation of beetles. • http://evolution.berkeley.edu/evosite/evo101/IIIADescent.shtml

  9. Evolution??? • Beetles of a different color • Most of the beetles in the population (say 90%) have the genes for bright green coloration and a few of them (10%) have a gene that makes them more brown. • Some number of generations later, things have changed: brown beetles are more common than they used to be and make up 70% of the population.

  10. Population: • All the individuals of a species that live together in one place at one time. • Ex: Alligators in the Everglades • http://www.google.com/imgres?imgurl=http://www.animalwebguide.com/Alligator-1.jpg&imgrefurl=http://www.animalwebguide.com/Alligator.htm&usg=__iIeUOzX6AWt62BkR893nxHD94B4=&h=542&w=405&sz=73&hl=en&start=39&zoom=1&tbnid=RKtrpdVswhg5eM:&tbnh=169&tbnw=140&ei=NLSgTffMNKHE0QHqkfn_BA&prev=/search%3Fq%3Deverglade%2Balligator%26um%3D1%26hl%3Den%26rlz%3D1G1GGLQ_ENUS398%26biw%3D1238%26bih%3D679%26tbm%3Disch0%2C963&um=1&itbs=1&iact=hc&vpx=885&vpy=253&dur=683&hovh=260&hovw=194&tx=129&ty=163&oei=LbSgTb-ZOYW_0QHVzcSWBQ&page=3&ndsp=15&ved=1t:429,r:3,s:39&biw=1238&bih=679

  11. Natural Selection: • Process by which organisms change in response to their environment. • http://jrenseyblog.wordpress.com/2011/07/

  12. Natural Selection cont’d • Individuals that have physical or behavioral traits that are better suited their environment are more likely to survive and reproduce than those that do not have such traits.

  13. Adaptation: • The changing of a species that results in its being better suited to its environment. • http://www.johnehrenfeld.com/2009/05/be-careful-with-adaptation.html

  14. List some examples of adaptations

  15. On the Origin of Species • Darwin did not publish his ideas on evolution until 1859. • He published On the Origin of Species by Means of Natural Selection

  16. Darwin’s ideas have been updated • Genes are responsible for inherited traits.

  17. Darwin’s ideas have been updated • Isolation leads to species formation. • Isolation: the condition in which two populations of the same species cannot breed with one another. • Populations of the same species living in different locations tend to evolve differently. http://williamcalvin.com/bk3/img/kaibab.gif

  18. Kaibab Squirrel Aberts Squirrel

  19. Species: • Group of organisms that are genetically similar and can produce fertile offspring.

  20. Darwin’s ideas have been updated • Extinction leads to species replacement. • Climate changes & natural disasters lead to extinction. • Extinct: species disappears permanently. • Species that are better suited to the new conditions replace the old species. http://hypebeast.com/image/2008/06/nike-plus-human-race-3.jpg

  21. The Theory of Evolution is Supported by Four Points • Variation exists within the genes of every population or species. Some human examples: __________________________________________

  22. The Theory of Evolution is Supported by Four Points • In a particular environment, some individuals of a population or species better suited to survive (as a result of variation) and have more offspring.

  23. The Theory of Evolution is Supported by Four Points • Over time, the traits that make certain individuals of a population able to survive and reproduce tend to spread in that population.

  24. The Theory of Evolution is Supported by Four Points • There is clear proof from fossils and many other sources that living species evolved from organisms that are extinct. http://www2.estrellamountain.edu/faculty/farabee/biobk/BioBookEVOLII.html#Evidence%20for%20Evolution

  25. QUESTIONS?

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