A History of Mass Extinctions on Earth

Billions of Years Ago Millions of Years Ago (Ma) 2.5 2.0 1.5 1.0 0.5 450 400 350 300 250 200 150 100 50 End Permian Extinction Cause: Massive climate and atmospheric change due to meteor- ite hit, mega- volcanoes that erupted Ordovician-Silurian Extinction Cause: An ice age (possibly caused by a gamma ray burst) resulted in falling sea for centuries Casualties: Trilobites, Cretaceous-Tertiary Extinction echinoderms and eurypterids, many fern like plants, many insects levels Snowball Earth Cause: Asteroid impact and volcanic activity Casualties: Brachio- pods, bivalves, echino- derms, bryozoans, corals Cause: Global ice age froze oceans Casualties: Every single dinosaur Survivors: Reptile mammal hybrid called lystrosaurus, amphib- ians, molds, fungus, weedy plants, ferns Casualties: Near sterilization of planet Survivors: Trilobites, coral reefs, bony fish, first land plants Survivors: Small mam- mals, turtles, snakes, lizards Survivors: A few microbes 2300 Ma 440-450 Ma 250 Ma 65 Ma 100% 80% 60% 40% 20% 0% 2500 Ma 364 Ma 199 Ma Triassic-Jurassic Extinction Oxygen Apocalypse Late Devonian Extinction Cause: Cyanobacteria's waste product oxygen poisoned the methane atmosphere, killing nearly every life form Cause: Sea level changes, possibly mega volcanoes Cause: Unknown – theories include ocean anoxia, ice age, and volcanism Casualties: Crurotarsi, conodonts, large amphibians Casualties: Pretty much all agnathan fish, coral reefs were almost entirely destroyed Casualties: Anaerobic organisms Survivors: Cyanobacte- ria, all oxygen breath- ing creatures Survivors: Dinosaurs Survivors: Tetrapods, land animals, insects, land plants Graphic by Stephanie Fox • io9.com EARTH'S DEADLIEST EVENTS PROTEROZOIC- NO3 SILURIAN PERIOD DEVONIAN PERIOD CARBONIFEROUS PERIOD PERMIAN PERIOD TRIASSIC PERIOD JURASSIC PERIOD CRETACEOUS PERIOD PALEOGENE PERIOD NEOGENE PERIOD Surviving Genera