1. The Permian Mass Extinction

2. What causes extinctions? 1.Competition from other organisms -Everything needs some space to live. -If there isn’t enough habitat/food/etc, one species must adapt, move, or die out. 2.Changes in the physical environment -Climate change -Animals must adapt or die out. 3.Chance events -Meteorite impacts, forest fires, tsunamis, etc.

3. Terrestrial life in the Permian  More continental area than any previous time in Earth’s history.  Wide variety of terrestrial animals: –insects, amphibians, reptiles, and therapsids (mammal-like reptiles), etc.  Wide variety of land plants: –gymnosperms (seed plants), and conifers (pine trees), etc.

4. Marine life in the Permian  Marine life was extremely abundant: –Common groups included the brachiopods, ammonids (squid-like animals), gastropods (sanils), bony fish, and sharks, etc.  Coral and trilobites were also present, but were less common than in earlier times.

5. BUT…life was in for some trouble  Approximately 246 million years ago, the largest mass extinction in the history of the Earth began.  90 - 95 % of all marine species went extinct.  Many land species went extinct as well.

6. What species were affected?  Marine animals that went extinct: –all trilobites, rugose (horn) and tabulate coral, and many others.  Marine animals that were dramatically affected but did not go extinct: –bryozoans, brachiopods, ammonids (squid), sharks, fish, echinoderms (star-fish, etc), and many more.  Why?

7. Glaciation Extinction Theory #1  Temperature cools across whole planet  Ice accumulates on continents  Lowers sea level  continental shelf is exposed  Makes living environment difficult and creates competition for living space.

8. Glaciation Extinction Theory #2  Ice accumulates on continents.  During cool climate periods, the interior of continents are often dryer.  This causes drastic climate fluctuations.  Makes survival difficult for many animals as a result of a change in the environment.

9. Super-Continent Formation Extinction Theory  Before the end of the Permian, there were numerous continents and large areas of continental shelf.

10. Devonian

11. Carboniferous

12. Permian

13. ...Super-continent theory, continued  As the continents come together, the total shelf area decreases.  This creates competition for living space, especially in the coastal marine environment.

14. Volcanic Eruption Extinction Theory  Large volcanic eruptions in “Siberia”  Large volumes of sulfate gases were released  Silica-rich lava = explosive eruptions = lots of dust  Gas and dust would lower atmospheric temperature  Environmental change

15. Which theory is correct?  Maybe all of them.  Maybe none of them.  They all deal with climate changes and changes in the total area that animals could live.  Most likely...a combination of all of them.