History of life on earth

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History of life on earth

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History of life on earth

  1. 1. A History of Life on Earth Chapter 5 Presented by Amith Reddy
  2. 2. Before Life Began • How old is the Earth ? 4.5 billion years • Big Bang - gravity causes dust particles to condense • Meteors for millions of years- how hot would the earth be? • Earth has to cool down - steam escapes and rain allows collection of water - earth now has…… • Atmosphere of Ammonia, Methane, water vapor, Co2, and Nitrogen • what is missing?
  3. 3. WHAT EVIDENCE DO SCIENTISTS USE? • Fossils! – trace – mold – cast – amber – imprint – petrified Images courtesy of the UC Museum of Paleontology Understanding Evolution: http://evolution.berkeley.edu." Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.
  4. 4. Outline Before Life Began The Emergence of Life Precambrian Life Paleozoic Life: The Cambrian Explosion Paleozoic Life: Ordovician to Devonian Mesozoic Life Marine life Marine life Terrestrial life Terrestrial plants and arthropods Vertebrates Paleozoic Life: Carboniferous and Permian The Cenozoic Era Terrestrial life Terrestrial life Aquatic life Aquatic life The adaptive radiation of mammals Pleistocene events
  5. 5. The Emergence of Life Early evolution of life on Earth
  6. 6. Endosymbiosis
  7. 7. Evolution of cell types
  8. 8. Precambrian Life • What do scientists think was alive way back then?? • Bacteria • This era lasted for billions of years until more living organisms evolved Dr Tom Tregenza © Tom Tregenza Dr Gordon Beakes © University of Newcastle upon Tynelicensed IMAGES for use through the Centre for Bioscience ImageBank,http://www.bioscience.heacademy.ac.uk/imagebank/" Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.
  9. 9. Stomatolites : Complex communities of (mostly) cyanobacteria produce all the atmospheric oxygen.
  10. 10. Paleozoic Era 540 Million years ago!! • • • • • • • • • Now the earth is getting larger life! First part of paleozoic is called cambrian Protists! Sea plants! Sea animals! Land plants! Land animals! what ended the paleozoic era?? Mass extinction! Dr. Thomas W. Kammer
  11. 11. Cretaceous – Tertiary Extension 65.5 mill years ago Permian – Triassic Extension (Great Dying) 251.4 mill years ago Ordovician – Silurian Extension 443.7 mill years ago
  12. 12. Species Extension in various periods of History
  13. 13. WHY DO WE HAVE DIFFERENT ERA’S? Image courtesy of the UC Museum of Paleontology Understanding Evolution: http://evolution.berkeley.edu."
  14. 14. Why Mass extinction ? How did they survive???
  15. 15. Which life, Marine or Terrestrial has faster growth or extinction ???
  16. 16. How did trees survive without roots ?
  17. 17. Formation of Earth
  18. 18. Why land moved or changed in Mesozoic life ?? Why they separate at different rate ? Why not all at once ?? What was the climate of the earth at this time ?
  19. 19. How/Why did only Gymnosperms first appeared than Angiosperms ???
  20. 20. How are they different ???
  21. 21. Mesozoic era 245 Million years ago!! • • • • • • • • Dinosaurs Reptiles Small mammals appear Birds evolve Plate tectonics what ended the mesozoic era? mass extinction! Meterorite ???
  22. 22. Image courtesy of the UC Museum of Paleontology Understanding Evolution: http://evolution.berkeley.edu."
  23. 23. Cenozoic Era 66 Million years ago! • Mammals flourish • Primates about 30 million years ago • Modern human species – about 200,000 years ago
  24. 24. licensed for use through the Centre for Bioscience ImageBank,http://www.bioscience.heacademy.ac.uk/imagebank/"
  25. 25. • Where are fossils usually found? • Who studies these? • How do scientists determine the age of something billions of years old? – Relative dating – Radiometric dating Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Understanding Evolution: http://evolution.berkeley.edu."
  26. 26. Evolution of life on land Q. Were animals or plants first? • Animals were first! Land-plants (not algae) only appeared about 450 million years ago. Q. When did the first flowering plants appear? • Only about 120 million years ago! Before that, ferns, mosses, and algae (incl. kelps etc.) Q. When did mammals appear first? • Before dinosaurs! ~220 million years ago.
  27. 27. Questions
  28. 28. Thank You

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