1 / 19

History of Current Life on Earth

History of Current Life on Earth. Theories and Ideas on What Has Happened Since Life Began. Modern Life. Modern Life. Cambrian Explosion ~ 500 mya All modern animal phyla appear in fossil record First records of modern animal life Five catastrophes = Five mass extinctions.

rodd
Download Presentation

History of Current Life on Earth

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. History of Current Life on Earth Theories and Ideas on What Has Happened Since Life Began

  2. Modern Life

  3. Modern Life • Cambrian Explosion • ~ 500 mya • All modern animal phyla appear in fossil record • First records of modern animal life • Five catastrophes = Five mass extinctions

  4. Ordovician-Silurian Extinction

  5. Ordovician-Sulurian Extinction • Occurred ~450 mya • Caused by glaciation • Dominant animals were marine • More than 25% of marine families went extinct

  6. Late Devonian Extinction

  7. Late Devonian Extinction • ~380 mya • Caused by cooling temperatures and a possible meteorite impact • Prior to extinction the dominant animals were reef builders. • About 22% of marine families perished

  8. Permian-Triassic Extinction

  9. Permian-Triassic Extinction • ~250 mya • Worst mass extinction • Up to 95% of all species on Earth suddenly became extinct • Reason unknown, believed that the ocean levels may have dropped

  10. End Triassic Extinction

  11. End Triassic Extinction • ~200 mya • Most likely caused by massive floods of lava erupting from the central Atlantic • Up to 22% of marine families • Vertebrate deaths unknown

  12. Cretaceous-Tertiary Extinction

  13. Cretaceous-Tertiary Extinction • ~65 mya • Cretaceous period lasted 150 million years • Extinction mostly likely caused by giant asteroid hit off of Mexico • 16% of marine families went extinct • 18% of vertebrates went extinct

  14. Fossil Record

  15. Fossil Record • Fossil record • Remains of a once living organism • Bones, molds, casts, footprints • Can be dated • Relative Dating • Estimates the age of events and fossils using basic stratigraphic rules • Provides a sequence of age • Absolute Dating • Based on the physical or chemical properties of the materials artifacts and fossils • Provides a numerical age

  16. Lucy

  17. Lucy • Discovered by a team working in Ethiopia with Donald Johanson • 40% of a skeleton of a member of Australopithecus afarensis • About 3.2 million years old • Small brain capacity (like apes) but walked bipedal (like hominids)

  18. Human Evolution

  19. Human Evolution • One current model looking at human evolution and where it occurred • Homo refers to human • Different species existed and were relations to each other, but did not necessarily give direct rise to each other • Many other hominines exist and most likely were common ancestors of those in the genus Homo

More Related