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Evolution: Change Over Time

Evolution: Change Over Time. Evolution: Change Over Time. The Evidence. The Evidence. Evolution: Change Over Time. Evolution: Change Over Time. The Evidence. The Evidence. Fossil Record. Defined : Collection of every known fossil Most fossils found in sedimentary rock

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Evolution: Change Over Time

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  1. Evolution: Change Over Time Evolution: Change Over Time The Evidence The Evidence Evolution: Change Over Time Evolution: Change Over Time The Evidence The Evidence

  2. Fossil Record • Defined: Collection of every known fossil • Most fossils found in sedimentary rock • Age determined by depth • Law of Superposition: new rock forms on top of older rock • Evidence Conclusions: • 1) Newer fossils are more complex • 2) Common ancestors: similarities between ancient & modern life

  3. Fossil Types • 1) Natural Cast: impressions left behind and filled in w/ minerals from water

  4. Fossil Types • 2) Permineralization: Minerals in water form around hard structures (shells, bones, teeth)

  5. Fossil Types • 3) Trace fossils: record life activities (foot prints, burrows)

  6. Fossil Types • 4) Amber: Tree resin (sap) hardens to trap creature

  7. Fossil Types • 5) Preserved remains: objects buried in ash, ice, bogs

  8. Isotopes are unstable in their nuclei, therefore they decay Isotopes have a known half life (rates of decay are known). Half life = number of years it takes for half of the isotopes to decay 14C has a half life of 5700 years, and 14N is a decay product Age determined by comparing ratio of 14C to 14N Wider ratio = older samples Radiometric Dating • Isotopes: atoms of the same element with differing neutrons • Ex: 12C and 14C • 12C = 6 protons + 6 neutrons • 14C = 6 protons + 8 neutrons

  9. Comparing old fossil to modern life shows change Ancient Kelp Modern Kelp

  10. 24 Hour Life Timeline Land plants & fungi Multicellular plants Land prokaryotes Amniotic egg Apes (LUCA) prokaryotes Fish (first vertebrates) Land animals Unicellular eukaryotes Dinosaurs extinct

  11. Missing Link Fossils • Show connections between groups of organisms • Archaeopteryx: shares both bird & reptile features • Basilosaurus: early whale with tiny hind legs • Evidence Conclusion : Indicates common ancestry

  12. flipper arm leg wing Homologous Structures walking flight grasping swimming • Defined: similar body structures with very different functions • Different environments lead to adaptations • Ex: The forelimbs of animals • Evidence Conclusion : Indicates common ancestry

  13. Vestigial Structures • Defined: Organs which have lost most or all their original function • Vestigial Human Parts: • Gill slits = once used to breath oxygen in water • Yolk sac = once used to nourish developing embryo • Tailbone = once used for balance • Appendix = once used to digest plants • Wisdom teeth = once used to grind plant tissue • Evidence Conclusion : Indicates common ancestry

  14. Human Embryo

  15. Snake femurs

  16. Blind Mole Rats

  17. Flightless Birds

  18. Biochemical Evidence • DNA, proteins, & amino acids compared • More related species have more similar biochemistry • Evidence Conclusion : Indicates common ancestry

  19. Embryo Development • Different species show similar development patterns • Different body plans become noticeable later in development • Evidence Conclusion : Indicates common ancestry

  20. Resistant Organisms • Antibiotics: chemicals designed to kill bacteria • Produced by other microorganisms to fight bacteria • Antibiotic Resistance: Bacteria are adapting to the use of antibiotics • Overuse & misuse speeds up the process • Importance: Bacteria infections are becoming harder to treat Bacteria Fungus

  21. Antibiotic Resistance Bad Good

  22. Most bacteria killed Strong Survive Bacterial Resistance Strong Reproduce

  23. Resistant Organisms • Pesticides: Chemicals designed to kill pests (rodents, insects) • Pesticides sprayed on crops to kill pests • Strong pests are left to reproduce • Pesticide Resistance: pests are adapting to the use of pesticides • Importance: Crops are being destroyed by pests "crop dusting"

  24. Quick Review • First life on earth were prokaryotes (bacteria) • Changing environments lead to adaptation • Much evidence indicates life has common ancestors

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