Mass Extinctions Question Flashcards
Extinction order
Ordovician, Late-Devonian, Permian, Triassic, Cretaceous
Intro hook
Each event has resulted in at least 75% of species lost, Permian the worst with 95% marine and 75% terrestrial (Shen and Zhang, 2017)
Ordovician - 445 mya
-1st pulse - global warming, 2nd pulse - volcanism further impacting (P.G, Bond, 2020), glaciation also possible, 85% species lost - mostly marine invertebrates
Late Devonian - 375 mya
anoxia + volcanism, Frasnian - Famenmian (F-F) extinction event = eustatic, several lesser extinctions as well (Wignall and Bond, 2008), 75% species - damage to reefs
Permian “The Great Dying” - 262 mya
massive mantle plume below Siberian traps, eruption, carbon release, global warming + acidification, 5 x 100km2 Siberia basalt (Saunders and Peichow, 2009), 95% marine, 75 terrestrial, niche for dinos
Triassic - 201 mya
Volcanism, breakup of Pangea, usual as well as lack of new species (as important), 80% species, many large amphibians, enabled dinosaurs to dominate
Cretaceous - 66 mya
Chicxulub crater, tsunami 30,000 x bigger (The Guardian, 2022), wildfires, ‘nuclear winter’, 76% lost, everything >50lbs, mammals survived
Similarities in causes
-Global warming + volcanism - Permian, Triassic, Devonian
-Ocean anoxia = Devonian and Ordovician
Differences in causes
Cretaceous - unlike any other = asteroid
Ordovician - possible evidence of glaciation of Gondwana supercontinent
Similarities in consequences
At least 75% of species lost, widespread biodiversity and plant life loss, Ordivician + Permian = major loss of marine life, Permian + Triassic = both allowed for the rise of dinos (eliminating comp + niches)
Differences in consequences
Triassic + Cretaceous had greater terrestrial impacts compared to Ordovician and Permian which had devastating marine impacts as well
Short conc
-They may differ and similar but overall they share the effect of devastating the earth
-knowledge needs to be used to warn humans of an anthropogenic 6th extinction - climate change
