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Mass Extinctions

Mass Extinctions. 1. What’s a mass extinction?. A sharp decrease in the number of species in a relatively short period of time . There different ways a mass extinction can occur including… Meteors Comets Global warming Ice age And more…. 2. The Ordovician-Silurian Extinction.

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Mass Extinctions

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  1. Mass Extinctions

  2. 1. What’s a mass extinction? • A sharp decrease in the number of species in a relatively short period of time. • There different ways a mass extinction can occur including… • Meteors • Comets • Global warming • Ice age • And more…

  3. 2. The Ordovician-Silurian Extinction • Caused by a drop in sea level as glaciers formed. • Killed about 25% of marine families • Killed 60% of marine genera http://www.sethwhite.org/images/ross%20island/barne%20glacier/barne%20glacier%20and%20crack%202.jpg

  4. 3. Late Devonian Extinction • About 364 million years ago • Not clear if it is 2 large mass extinctions or a series of small extinctions • About 22% of marine families were killed • About 57% of the genera were killed • Suggested that a asteroid impact was the prime cause http://www.ecoenquirer.com/global-warming-asteroid.jpg

  5. 4. Permian-Triassic extinction • Most likely due to volcanic eruption, • an asteroid impact • or a near by super nova. http://mahi.ucsd.edu/Gabi/erth10.dir/lava-fountain.jpeg

  6. Permian Catastrophe • Informally called the “Great Dying” • The most severe extinction • 96% of all marine species were killed • 70% of terrestrial vertebrate were killed • Occurred over a few million years • Normal levels of biodiversity took 6 million years to recover http://www.biederman.net/leslie/animations/explosion.jpg

  7. 5. End Triassic extinction • 199 - 214 million years ago • caused by massive floods or lava erupting from central Atlantic province – an event that triggered the opening of the Atlantic Ocean • The volcanism may have lead to deadly global warming • 22% of Marine families • 52% of marine genera • Vertebrate deaths unknown Power Point Template

  8. 6. Cretaceous-Tertiary extinction http://karinahall.txc.net.au/MoonExtinctionCycle/comet4a.jpg

  9. 6. Cretaceous-Tertiary extinction • 65 million years ago • Meteor strike in the Gulf of Mexico • Chixclub • 200 km crater • 9 mile wide meteor

  10. Chain reaction of Meteor Impact • Forest fires • Tidal Waves • Volcanic activity • Greatly reduced sunlight • Toxic gasses • Climate change

  11. 7. The Big Five • Ordovician-Silurian extinction - 439 million years ago, • Late Devonian extinction- 364 million years ago • Permian-Triassic extinction - 251 million years ago • End Triassic extinction, - 199 million to 214 million years ago • Cretaceous-Tertiary extinction, about 65 million years ago

  12. 8. The Sixth Mass Extinction? • Holocene extinction • Coincides with the appearnace of Homo sapiens • Over hunting • Habitat destruction • Pollution • 500,000 – 1,000,000 extinct species

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