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Mass Extinction

Mass Extinction. Jacksury Puerta. What is E xtinction ?. Extinction is the process by which a species become extinct, no longer existing and living in the world. Extinction is a normal part of evolution.

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Mass Extinction

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  1. Mass Extinction Jacksury Puerta

  2. What is Extinction? • Extinction is the process by which a species become extinct, no longer existing and living in the world. • Extinction is a normal part of evolution. • Species come and go continually, around 99.9% of all those that have ever existed are now extinct. • Mass extinctions are events in which a very significant percentage of the species on the planet go extinct.

  3. Five Mass Extinctions in the history of the planet Earth • Ordovician-Silurian, 435 million years ago • Late Devonian, 370 million years ago • Permian, 250 million years ago • Triassic, 205 million years ago • Cretaceous-Tertiary, 65 million years ago

  4. Ordovician-Silurian Extinction • 439 million years ago • Caused by a drop in sea level as glaciers formed, then by rising sea levels as glaciers melted. • Approximately 60% of marine genera were killed and 25% of marine families

  5. Late Devonian Extinction • 364 million years ago • series of extinction over several million years • Caused by a asteroid impact and global cooling after the impact • Approximately 57% of the genera were killed and 22% of marine families • Life in the shallow sea were the most affected

  6. Permian Extinction • Known as the “Great Dying”, most severe extinction • 96% of all marine species were killed • 70% of land-living animal life were killed • Caused by change in climate and sea level when forces of the earth’s continents merge together.

  7. Triassic Extinction • 2 or 3 phases of extinction • 52% of marine genera and 22% of marine families • Caused by massive floods or lava erupting from central Atlantic province led by global warning

  8. Cretaceous-Tertiary • Known as the K/T extinction • Famous for the death of the dinosaurs • 75% of all species became extinct • Happened at a rapid rate • Caused: by a volcanic event that produced the Deccan traps of India • An asteroid hit somewhere in the golf of Mexico in the Yucatan Peninsula

  9. Sixth Extinction • Known as the Holocene extinction • This extinction event started at the end of the last ice age, around 13,000 BP. • Rapid pace - hundred years rather than thousand years seen by the big five mass extinction. • The rapid loss of species we are seeing today is estimated to be between 1,000 and 10,000 times higher than the natural extinction rate. • E. O. Wilson estimates that 30,000 species per year (or three species per hour) are being driven to extinction.

  10. Sixth Extinction The Extinction of nearly all forms of the large mammals known asMegafauna, and the remaining species almost all threatened with extinction in the near future.

  11. What's causing this sixth extinction ? • Unlike previous extinctions they were caused by climate change, the current crisis is caused by human activities. • Habitat destruction • Pollution • Overpopulation • Over-harvesting (hunting, fishing, and gathering) • Invasive species • By the year 2100, due to human activities half of the world's marine and land species will go extinct.

  12. This graph shows the rise in extinctions since the human population

  13. What can we do??? • The world’s leading scientists suggest that conservation measures, sustainable development, stabilization of the human population and the support of environmentally responsible economic development will be essential in halting the extinction crisis.

  14. References • http://www.bbc.co.uk/nature/extinction_events • http://www.princeton.edu/~achaney/tmve/wiki100k/docs/Holocene_extinction_event.html • http://www.rewilding.org/thesixthgreatextinction.htm • http://www.biologicaldiversity.org/programs/biodiversity/elements_of_biodiversity/extinction_crisis/ • http://www.actionbioscience.org/newfrontiers/eldredge2.html

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