Downloaded 417 times
Uploaded byAmith Reddy
History of life on earth
This document provides an overview of the history of life on Earth from its beginnings over 4.5 billion years ago to the present. It describes how the early Earth formed and cooled, allowing for the emergence of the first life forms like bacteria in the Precambrian era. The Cambrian explosion saw the first major diversification of multicellular life, including in the seas. Subsequent eras like the Paleozoic, Mesozoic, and Cenozoic witnessed further evolution and radiation of life on land and sea, including plants, insects, dinosaurs, mammals, and eventually humans. Mass extinctions periodically wiped out much life, paving the way for new species to evolve and fill ecological niches.
More Related Content
Similar to History of life on earth
History of life on earth
- 1. A History ofLife on Earth Chapter 5 Presented by Amith Reddy
- 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. WHAT EVIDENCE DOSCIENTISTS 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. Outline Before Life Began TheEmergence 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
- 6. The Emergence ofLife Early evolution of life on Earth
- 7.
- 10. Evolution of celltypes
- 11. Precambrian Life • Whatdo 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.
- 14. Stomatolites : Complexcommunities of (mostly) cyanobacteria produce all the atmospheric oxygen.
- 19. Paleozoic Era 540 Millionyears 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
- 20. Cretaceous – TertiaryExtension 65.5 mill years ago Permian – Triassic Extension (Great Dying) 251.4 mill years ago Ordovician – Silurian Extension 443.7 mill years ago
- 21. Species Extension invarious periods of History
- 22. WHY DO WEHAVE DIFFERENT ERA’S? Image courtesy of the UC Museum of Paleontology Understanding Evolution: http://evolution.berkeley.edu."
- 23. Why Mass extinction? How did they survive???
- 24. Which life, Marineor Terrestrial has faster growth or extinction ???
- 25. How did treessurvive without roots ?
- 27.
- 28. Why land movedor 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 ?
- 29. How/Why did onlyGymnosperms first appeared than Angiosperms ???
- 30. How are theydifferent ???
- 32. Mesozoic era 245 Millionyears ago!! • • • • • • • • Dinosaurs Reptiles Small mammals appear Birds evolve Plate tectonics what ended the mesozoic era? mass extinction! Meterorite ???
- 33. Image courtesy ofthe UC Museum of Paleontology Understanding Evolution: http://evolution.berkeley.edu."
- 34. Cenozoic Era 66 Millionyears ago! • Mammals flourish • Primates about 30 million years ago • Modern human species – about 200,000 years ago
- 35. licensed for usethrough the Centre for Bioscience ImageBank,http://www.bioscience.heacademy.ac.uk/imagebank/"
- 40. • Where arefossils 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."
- 43. Evolution of lifeon 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.
- 44.
- 45.