Major mass extinctions of species
Extinction event(s) Date (millions of year ago) Organisms most affected Estimate of percentage of species made extinct Cause(s)
Late Cambrian (series) c. 488 trilobites, brachiopods, conodonts (primitive toothed vertebrates), ?soft-bodied arthropods ? ?change in sea level
Late Ordovician c. 444 echinoderms, brachiopods, trilobites, ostracods, nautiloids 70–85 glaciation and fall in sea levels
Late Devonian (series) c. 360 cephalopods, corals, brachiopods, bryozoans, echinoderms, trilobites, ammonites, agnathans, armoured fishes 70–83 ?global cooling and reduced oxygen levels in deeper waters
Late Permian (Permo-Triassic; PTr) 251 corals, crinoids, ammonites, brachiopods, bryozoans, trilobites, land plants, insects, terrestrial vertebrates <95 ?volcanic activity with consequent global warming and changes in marine environment
Late Triassic 200 brachiopods, ammonites, bivalve and cephalopod molluscs, marine reptiles, conodonts, labyrinthodonts (primitive amphibians), insects 80 ?climatic changes due to continental drift
Cretaceous- Tertiary (K–T) 65 dinosaurs, flying reptiles, ammonites, fish, brachiopods, planktonic organisms, plants 75–85 ?meteorite collision (Alvarez event)
From A Dictionary of Biology in Oxford Reference.
Subjects: Biological Sciences.