5 Mass Extinctions

5 Mass Extinctions

1. Ordovician

   • 25% to 50% became extinct
   • sea life (i.e. trilobites, brachiopods, graptolites) drastically reduced in number

2. Devonian

   • 75% became extinct
   • water bed dried up
   • sea bed became devoid of oxygen

3. Permian

   • 96% became extinct
   • "The Great Dying"

4. Triassic

   • marine reptiles, some large amphibians, many reef-building creatures, large numbers of cephalopod mollusks died
   • plants were not so badly affected

5. Cretaceous

   • K/T extinction
   • death of dinosaurs, many flowering plants, and last of pterosaurs