Intro to evolution


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Intro to evolution

  1. 1. Evolution
  2. 2. History4.6 billion Years AgoThe Earth forms and is bombarded by meteorites and comets.
  3. 3. 3.5 billion Years AgoUnicellular life evolves. Photosynthetic bacteria begin to release oxygen into the atmosphere.
  4. 4. 555 million Years AgoMulti-cellular marine organisms are common. The diverse assortment of life includes bizarre-looking animals like Wiwaxia.
  5. 5. 500 million Years AgoFish-like vertebrates evolve. Invertebrates, such as trilobites, crinoids, brachiopids, and cephalopods, are common in the oceans.
  6. 6. 450 million Years AgoArthropods move onto the land. Their descendants evolve into scorpions, spiders, mites, and millipedes.
  7. 7. 400 million Years Ago Pre-historic Shark
  8. 8. 360 million Years Ago Four-limbed vertebrates move onto the land, and seed plants and large forests appear. The Earths oceans support vast reef systems.
  9. 9. 250 million Years AgoThe supercontinent called Pangea forms. Conifer-like forests, reptiles, and synapsids (the ancestors of mammals) are common.
  10. 10. 248 million Years Ago Over 90% of marine life and 70% of terrestrial life go extinct during the Earths largest mass extinction. Ammonites are among the survivors.
  11. 11. 225 million Years Ago Dinosaurs and mammals evolve. Pangea has begun to break apart.
  12. 12. 130 million Years AgoAs the continents drift toward their present positions,the earliest flowers evolve, and dinosaurs dominate thelandscape. In the sea, bony fish diversify.
  13. 13. 65 million Years AgoA massive asteroid hits the Yucatan Peninsula, and ammonites and non-avian dinosaurs go extinct. Birds and mammals are among the survivors.
  14. 14. 4 million Years AgoIn Africa, an early hominid, affectionately named "Lucy" by scientists, lives (in Ethiopia). The ice ages begin, and many large mammals go extinct.
  15. 15. 130 000 Years AgoAnatomically modern humans evolve. Seventy thousand years later, their descendents create cave paintings — early expressions of consciousness.
  16. 16. EVOLUTION (Think/Pair/Share)
  17. 17. EVOLUTION (Think/Pair/Share)Biological evolution is descent with modification. This encompasses small-scale evolution (changes in gene frequency in a population from one generation to the next) and large- scale evolution (the descent of different species from a common ancestor over many generations).Evolution helps us to understand the history of life.
  18. 18. The Theory of EvolutionWhat is a theory? (Think/Pair/Share)(Hint! Think of atomic or cell theories... Or the theory of relativity.)
  19. 19. Everyday: An educated guessScientific: An explanatory model that accounts for a body of facts that have been repeatedly confirmed. Theories provide a basis for explaining observations of the natural world and for making predictions.Scientific theories are confirmed explanations of nature and are the most reliable, rigorous, and comprehensive form of scientific knowledge.