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Regeants Evidence for Evolution
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Regeants Biology Evidence for Evolution 2007

Regeants Biology Evidence for Evolution 2007

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  • The avian nature of the brain and inner ear of Archaeopteryx (Alonso et al. 2004) - Archaeopteryx, the earliest known flying bird from the Late Jurassic period, exhibits many shared primitive characters with more basal coelurosaurian dinosaurs (the clade including all theropods more bird-like than Allosaurus), such as teeth, a long bony tail and pinnate feathers. However, Archaeopteryx possessed asymmetrical flight feathers on its wings and tail, together with a wing feather arrangement shared with modern birds. This suggests some degree of powered flight capability but, until now, little was understood about the extent to which its brain and special senses were adapted for flight. Alonso et al. (2004) investigated this problem by computed tomography scanning and three-dimensional reconstruction of the braincase of the London specimen of Archaeopteryx. A reconstruction of the braincase and endocasts of the brain and inner ear suggest that Archaeopteryx closely resembled modern birds in the dominance of the sense of vision and in the possession of expanded auditory and spatial sensory perception in the ear. Alonso et al. (2004) concluded that Archaeopteryx had acquired the derived neurological and structural adaptations necessary for flight. An enlarged forebrain suggests that it had also developed enhanced somatosensory integration with these special senses demanded by a lifestyle involving flying ability.
  • There are innumerable intermediate & transitional forms
    Whales as land creatures returning to the water….
    Where are the intermediate forms of whale ancestors?
    Cartoon making fun of this idea.
    The cartoons disappeared 10-12 years ago when this fossil was found.
    Ambilocetic natans = “Walking whale who likes to swim”
    4-5 intermediate forms all found in last 2 decades
    Indus River valley in between India & Pakistan.
  • The evolution of resistance to insecticides in hundreds of insect species is a classic example of natural selection in action.
    The results of application of new insecticide are typically encouraging, killing 99% of the insects.
    However, the effectiveness of the insecticide becomes less effective in subsequent applications. The few survivors from the early applications of the insecticide are those insects with genes that enable them to resist the chemical attack. Only these resistant individuals reproduce, passing on their resistance to their offspring. In each generation the % of insecticide-resistant individuals increases.

Transcript

  • 1. Evidence for Evolution by Natural Selection Hunting for evolution clues… Elementary, my dear, Darwin! Regents Biology 2006-2007
  • 2. Evidence supporting evolution  Fossil record  shows change over time  Anatomical record  comparing body structures  homology & vestigial structures  embryology & development  Molecular record  comparing protein & DNA sequences  Artificial selection human caused evolution  Regents Biology
  • 3. 1. Fossil record  Layers of rock contain fossils  new layers cover older ones  creates a record over time  fossils show a series of organisms have lived on Earth  over a long period of time Regents Biology
  • 4. Fossils tell a story… the Earth is old Life is old Life on Earth has changed Regents Biology
  • 5. Evolution of birds Today’s organisms descended from ancestral species Fossil of Archaeopteryx  lived about 150 mya  links reptiles & birds Regents Biology
  • 6. We found the fossil — no joke! Land Mammal ? e e th r ? re a iate Whe rmed inte sils? fos Complete series of transitional fossils Someone’s idea of a joke! Regents Biology But the joke’s on them!! Ocean Mammal ? ?
  • 7. Evolution from sea to land  2006 fossil discovery of early tetrapod  4 limbs  Missing link from sea to land animals Regents Biology
  • 8. 3. Anatomical record Animals with different structures on the surface But when you look under the skin… It tells an evolutionary story of common ancestors Regents Biology
  • 9. Compare the bones  The same bones under the skin  limbs that perform different functions are built from the same bones How could these very different animals have the same bones? Regents Biology
  • 10. Homologous structures  Structures that come from the same origin  homo- = same  -logous = information  Forelimbs of human, cats, whales, & bats  same structure  on the inside same development in embryo  different functions   on the outside  evidence of common ancestor Regents Biology
  • 11. But don’t be fooled by these…  Analogous structures  look similar  on the outside same function  different structure & development  How is a bird like a bug?   on the inside different origin  no evolutionary relationship Solving a similar problem with a similar solution Regents Biology
  • 12. Analogous structures  Dolphins: aquatic mammal  Fish: aquatic vertebrate both adapted to life in the sea  not closely related  Watch the tail! Regents Biology
  • 13. Convergent evolution  3 groups with wings  Does this mean they have a recent common ancestor? They just came up with the NO! same answer! Regents Biology Flight evolved 3 separate times — evolving similar solutions to similar “problems”
  • 14. Convergent evolution led to mimicry  Why do these pairs look so similar? Monarch male Viceroy male poisonous edible Which is the moth vs. the bee? fly vs. the bee? Regents Biology fly bee moth bee
  • 15. Vestigial organs  Hind leg bones on whale fossils Why would whales have pelvis & leg bones if they were always sea creatures? Because they used to walk on land! Regents Biology
  • 16. Comparative embryology  Development of embryo tells an evolutionary story  similar structures during development all vertebrate embryos have a “gill pouch” at one stage of development Regents Biology
  • 17. 3. Molecular record  Comparing DNA & protein structure  everyone uses the same genetic code!  DNA Human Macaque Dog Bird Frog Lamprey 8 32 45 67 125  compare common genes  compare common proteins number of amino acids different from human hemoglobin 0 10 20 30 40 50 60 70 80 90 100 110 120 Regents Biology
  • 18. Building “family” trees Closely related species are branches on the tree — coming from a common ancestor Regents Biology
  • 19. 4. Artificial selection  How do we know natural selection can change a population? we can recreate a similar process  “evolution by human selection”  “descendants” of wild mustard Regents Biology
  • 20. Selective Breeding Humans create the change over time Regents Biology “descendants” of the wolf
  • 21. Artificial Selection …and the examples keep coming! I liked breeding pigeons! Regents Biology
  • 22. Artificial Selection gone bad!  Unexpected consequences of artificial selection Pesticide resistance Antibiotic resistance Regents Biology
  • 23. Insecticide resistance  Spray the field, but…  insecticide didn’t kill all individuals  variation resistant survivors reproduce  resistance is inherited  insecticide becomes less & less effective  Regents Biology
  • 24. Regents Biology
  • 25. Any Questions?? Regents Biology 2006-2007
  • 26. Natural Selection of Strawfish  How does natural selection affect genes?  How do genes affect evolution? Regents Biology 2006-2007
  • 27. 1. No Predator Preferences FISH blue ALLELES green yellow blue yellow Gen. 1 25% 50% 25% 50% 50% Gen. 4 27% 55% 18% 55% 45% No selection force in one specific direction. No clear pattern of change. Regents Biology
  • 28. 2. Predator Prefers BLUE FISH blue ALLELES green yellow blue yellow Gen. 1 25% 50% 25% 50% 50% Gen. 4 13% 50% 37% 38% 62% Selection against blue. Fewer Regents Biology blue fish and fewer blue alleles.
  • 29. 3. Predator Prefers GREEN FISH blue ALLELES green yellow blue yellow Gen. 1 25% 50% 25% 50% 50% Gen. 4 36% 28% 36% 50% 50% Selection against green. Fewer Regents Biologygreen fish but same variation in alleles.
  • 30. 4. GREEN is Camouflaged FISH blue ALLELES green yellow blue yellow Gen. 1 25% 50% 25% 50% 50% Gen. 4 20% 60% 20% 50% 50% Selection against blue & yellow. More green fish but same variation in alleles. Regents Biology
  • 31. Parallel Evolution Niche Placental Mammals Burrower not closely related Mole Anteater Anteater Nocturnal insectivore Climber marsupial mammal Glider Stalking predator Chasing predator Regents Biology Australian Marsupials Mouse Marsupial mole Numbat Marsupial mouse placental mammal Spotted cuscus Lemur Flying squirrel Ocelot Sugar glider Tasmanian cat filling similar roles in nature, Wolf so have similar adaptations “wolf” Tasmanian
  • 32. Vestigial organs  Structures on modern animals that have no function remains of structures that were functional in ancestors  evidence of change over time   some snakes & whales have pelvis bones & leg bones of walking ancestors  eyes on blind cave fish  human tail bone Regents Biology