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Lecture 13

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Lecture 13

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  1. Lecture 13 February 21, 2002 Chapter 18 The Evolution of Animal Diversity Chapter 31 Plants

  2. Learning Objectives (1 of 2) • Define • Class Aves • Class Mammalia • List: • The reptile-like characters of Archaeopteryx • Recite: • 2 pieces of evidence that birds evolved from reptiles • 3 basic types of mammals

  3. Learning Objectives (2 of 2) • Recall: • The species of General Sherman • Contrast • Monocots and Dicots • Xylem and phloem

  4. Reptiles • Evolved from amphibians • Can live on land for entire life • 2 Major features: • Developed “amniotic land egg” to do this • No longer require water for reproduction • Water-proof skin • To conserve water

  5. Ex: Dinos are Reptiles

  6. Ex: Lizards are Reptiles

  7. Ex: Crocodilians are Reptiles

  8. Bird Evolution • Believed to have evolved from small, carnivorous dinosaurs • Dino hand bones similar to bird wing bones • When given certain hormones, chicken embryos will develop teeth!

  9. Archaeopteryx • A very early bird! • Reptilian characteristics • Long tail • Wing claws • Teeth • Scales on feet

  10. Class Aves • All birds: • Have feathers! • Are endothermic (warm-blooded) • Lay eggs

  11. Class Mammalia • All mammals: • Have fur (yes, even whales & dolphins) • Feed their offspring milk • Are endothermic

  12. Three Basic Kinds of Mammals • Monotremes: • They lay eggs! • Include platypus • Marsupials: • Carry young in pouch • Ex: kangaroos, opposums • Eutherians (placentals): • Longer pregnancy • More developed young

  13. To Sum Up:

  14. Question • Which group evolved earliest in the history of life? • Fish • Dinosaurs • Mammals • Birds

  15. Another Question • Are birds animals? • Are fish animals?

  16. 7th Inning Stretch

  17. World’s Biggest Plant • The General Sherman Tree • Species is Sequoiadendron gigantea • Central California • 2500 years old!!! • National Park Service site • US Geological Survey site

  18. Angiosperms • These are flowering plants • Two basic types: • Monocots • Dicots

  19. Monocots • Have one “seed leaf” • Root network very fibrous • Leaves have parallel veins • Examples: orchids, bamboos, palms, grasses (including rice, other grains)

  20. Dicots • Have two “seed leaves” • One main taproot plus root hairs • Leaves have multiply branched veins • Ex: trees, shrubs, carrots

  21. Question: • Where would we classify pine trees?

  22. Answer: • Trick question: they aren’t angiosperms • They’re gymnosperms (no flowers!)

  23. Conductive Tissues • Xylem • Phloem

  24. Xylem • Contains water-conducting cells • Carries water and nutrients toward the leaves

  25. Phloem • Contains food conducting cells • Transports sugars to tissues, roots