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Varieties of life forms

Varieties of life forms. Figure 1.4C-F. Clown, Fool, or Well Adapted?. All organisms have evolutionary adaptations Inherited characteristics that enhance their ability to survive and reproduce blue-footed booby Large, webbed feet help propel the bird through water at high speeds.

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Varieties of life forms

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  1. Varieties of life forms Figure 1.4C-F

  2. Clown, Fool, or Well Adapted? • All organisms have evolutionary adaptations • Inherited characteristics that enhance their ability to survive and reproduce • blue-footed booby • Large, webbed feet help propel the bird throughwater at high speeds

  3. Specialized salt-secreting glands manage salt intake while at sea • A streamlined shape, large tail, and nostrils that close are useful for diving

  4. Evolution explains the unity and diversity of life • Charles Darwin synthesized the Theory of Evolution by natural selection • Theory vs hypothesis • Evolution is the core theme of biology Figure 1.6A

  5. The voyage of the Beagle Great Britain Europe NorthAmerica PacificOcean AtlanticOcean Africa GalápagosIslands Equator SouthAmerica Australia Andes Cape ofGood Hope Tasmania Cape Horn NewZealand Tierra del Fuego Figure 13.1B

  6. Prevalent ideas at Darwin’s time • species are fixed • Earth is about 6,ooo yrs old

  7. New ideas proposed • Fossils indicated the earth was very • Lyell, a geologist, argued that land forms changed constantly. • Lamarck proposed that organisms changed and these changes were passed to progeny.

  8. similarities between living and fossil organisms • the diversity of life on the Galápagos Islands, such as blue-footed boobies and giant tortoises • While on the voyage of the HMS Beagle in the 1830s, Charles Darwin observed Figure 13.1A

  9. Darwin became convinced that the Earth was old and continually changing • Mex. marine snail shells on high mtns • He concluded that living things also change, or evolve over generations • He also stated that living species descended from earlier life-forms: descent with modification

  10. Darwin proposed natural selection as the mechanism of evolution • Darwin observed that • organisms produce more offspring than the environment can support • organisms vary in many characteristics • these variations can be inherited

  11. Darwin concluded that individuals best suited for an environment are more likely to survive and reproduce than those less well adapted • As a result, the proportion of individuals with favorable characteristics increases • Populations gradually change in response to the environment

  12. natural selection explains the mechanism of evolution (1) Population with varied inherited traits Pesticide-resistant insects Antibiotic-resistant bacteria (2) Elimination of individuals with certain traits (3) Reproduction of survivors Figure 1.6B

  13. Charles Darwin, 1874 Figure 13.1x2

  14. Alfred Wallace Figure 13.1x6

  15. Darwin cartoon Figure 13.1x3

  16. Evolution happens when populations of organisms with inherited variations are exposed to environmental factors that favor the reproductive success of some individuals over others • Natural selection is the editing mechanism • Evolution is based on adaptations Figure 1.6C

  17. Fossils provide strong evidence for evolution • Hominid skull • Petrified trees Figure 13.2A, B

  18. Ammonite casts • Fossilized organic matter in a leaf Figure 13.2C, D

  19. Scorpion in amber • “Ice Man” • acid bogs Figure 13.2E, F

  20. Mammoth tusks Figure 13.2x4

  21. fossils show that organisms have appeared in a historical sequence • Many fossils link early extinct species with species living today • hind leg bones of fossil whales Figure 13.2G, H

  22. Other evidence for evolution • Biogeography • Comparative anatomy • Comparative embryology Human Cat Whale Bat Figure 13.3A

  23. Molecular biology - protein “clocks” Human Rhesus monkey Mouse Chicken Frog Lamprey Last commonancestor lived26 million yearsago (MYA),based onfossil evidence 80 MYA 275 MYA 330 MYA 450 MYA Figure 13.3B

  24. No predestined goal of evolution Figure 15.8

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