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Evolution

Evolution. Definition: Process of change through time. Theory of Evolution. Provides an explanation for the differences in structure, function, and behavior among life forms Evolution is based on COMMON ANCESTORY!. One Common Ancestor - Protozoa. Evidence of Evolution. Fossils:

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Evolution

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  1. Evolution Definition: Process of change through time

  2. Theory of Evolution • Provides an explanation for the differences in structure, function, and behavior among life forms • Evolution is based on COMMON ANCESTORY!

  3. One Common Ancestor - Protozoa

  4. Evidence of Evolution • Fossils: • Remains of organisms preserved in sedimentary rock, amber, ice, or tar

  5. Upper Strata – more complex organisms/youngest Lower Strata – less complex/oldest more complex less complex

  6. Comparative Cytology • The cell is the unifying structure for all living things • Organelles similar in most organisms

  7. Comparative Biochemistry • Nucleic Acids similar in all organisms (DNA/RNA) • Similar proteins (enzymes, hormones) • More similarities  More closely related

  8. Comparative Anatomy • Similarity in bone structure • Homologous Structure: Same structure different function • EX. Arms of humans, flippers of whales, wings of bat

  9. Homologous Structures Notice that the types and number of bones are relatively the same.

  10. Comparative Embryology • Similar embryological structure Common ancestry ***Mature growth is very different from embryological growth.

  11. Comparative Embryology • Notice that as organisms develop they become more and more distinguishable from one another.

  12. Vestigial Structure: • Parts that no longer serve a purpose • Structures were used in the past • Genes still produce these structures • Ex. Appendix, tail bone (coccyx)

  13. Charles Darwin Origin of Specieswritten in 1859 Studied finches, found differences on the Galopogos Islands Theory of Evolution- evolution based on variation and natural selection **Natural Selection: evolution is controlled by nature rather than by people.

  14. Theory of Evolution • Based theories on species variation and natural selection.- (There are 5 points to natural selection) 1.Overproduction- within a population more offspring are born than can possibly survive. 2.Competition- depends on number of individuals in a population struggle for survival - compete for food, shelter, living space

  15. Darwin (cont.) 3.Survival of the fittest- the “strongest” or best adapted to its environment will survive. 4. Reproduction- individuals that survive will reproduce and transmit favorable traits and variations to offspring.

  16. Darwin (cont.) 5. Speciation- new species have evolved from a COMMON ANCESTOR

  17. Weakness of Darwin’s Theory • Even though Darwin was able to tell us that there were many variations of all living things on the planet….. -He could not explain why. -Did not explain how variations arose.

  18. Darwin’s Theory

  19. Hugo DeVries • Hugo DeVries- - Found that something called a mutation were the source of variation in a population. - Favorable mutations among competing species resulted in modern species.

  20. Modern Evolutionary Theory • The Modern Evolutionary Theory supports Darwin's theory of variation and natural selection but incorporates the reason for the variation (mutation).

  21. What Produces Variation? • Variation: mutation and natural selection. • Mutations: spontaneous • Sexual reproduction - sorting and recombination of alleles.

  22. Examples of Evolution in Modern Times 1. Peppered Moth: light vs. dark (industrialization influence) • Moth was originally light in color  a mutation occurred  moth turned black  at same time the trees were getting darker because of industrialization, those that were dark blended into the trees better and SURVIVED

  23. 2. Insect resistance to insecticide: Insect gets a mutation and becomes resistant to the insecticide • Resistance is not in response to insecticide. (Insecticide=spray that kills insects) • Bacteria resistant to penicillin: • One bacteria becomes resistant to PCN bacteria reproduce ASEXUALLY  offspring are also resistant

  24. Modern Evolutionary Theory (cont.) • -involves the struggle of organisms to survive and reproduce in a given environment. • Good traits will passed onand will increase in frequency within a population • Bad traits will decrease in frequencywithin a population

  25. Geographic Isolation • Favors speciation (development of new species) by segregating a small group from the main population. • Ex. Mountains, deserts, cities, bodies of water.

  26. Reproductive Isolation • As a result of geographic isolation, organisms become so different they cannot mate and produce fertile offspring therefore a new species evolves

  27. 2 Theories of Evolution Rate • Gradualism: • - evolutionary change is slow, gradual and continuous.

  28. Punctuated Equilibrium: • - long periods of stability interrupted by significant change.

  29. Gradualism Punctuated Equilibrium

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