|Era ||Period ||Major Events ||MYA |
|Cenozoic ||Quaternary ||Human evolution ||2.6 |
|Neogene ||Modern mammal and bird families become recognizable. Ancestor of apes. ||23 |
|Paleogene ||Extinction of the non-avian dinosaurs. Mammals diversify. Evolution and dispersal of flowering plants. |
Chicxulub impact and the K-Pg extinction event.
|Mesozoic ||Cretaceous ||Flowering plants proliferate, along with new insects. Many new types of dinosaurs evolve, as do modern crocodilians and sharks. Birds toothed and toothless coexist with pterosaurs. Marsupials and placental mammals appear. ||145 |
|Jurassic ||Gymnosperms (especially conifers, Bennettitales and cycads) and ferns common. Many types of dinosaurs. Mammals common but small. First birds and lizards. ||201 |
|Triassic ||Archosaurs dominant on land as dinosaurs and in the air as pterosaurs. First mammals and crocodilia appear. Dicroidium flora common on land. Modern corals and insects appear. ||251 |
|Paleozoic ||Permian ||Permian-Triassic extinction event occurs (251 MYA): 95% of life on Earth becomes extinct. |
Coal-age flora are replaced by cone-bearing gymnosperms (the first true seed plants) and by the first true mosses. Beetles and flies evolve.
|Winged insects radiate suddenly; some are quite large. Amphibians common and diverse. First reptiles and coal forests (scale trees, ferns, club trees, giant horsetails, Cordaites, etc.). |
Large primitive trees, first land vertebrates, and amphibious sea-scorpions live amid coal-forming coastal swamps. Lobe-finned rhizodonts are dominant big fresh-water predators. In the oceans, early sharks are common and quite diverse. Corals very common, but trilobites and nautiloids decline.
|Devonian ||First seed-bearing plants. First trees, and first (wingless) insects. Strophomenid and atrypid brachiopods, rugose and tabulate corals, and crinoids are all abundant in the oceans. Goniatite ammonoids are plentiful, while squid-like coleoids arise. Trilobites and armoured agnaths decline, while jawed fishes (placoderms, lobe-finned and ray-finned fish, and early sharks) rule the seas. ||419 |
|Silurian ||First vascular plants. First jawed fishes, as well as many armoured jawless fish, populate the seas. Sea-scorpions reach large size. Tabulate and rugose corals, brachiopods, and crinoids all abundant. Trilobites and mollusks diverse; graptolites not as varied. ||444 |
|Ordovician ||First life on land. |
(green plants and fungi)
Invertebrates diversify into many new types (e.g., long straight-shelled cephalopods). Early corals, articulate brachiopods, bivalves, nautiloids, trilobites, ostracods, bryozoa, many types of echinoderms (crinoids, cystoids, starfish, etc.), branched graptolites, and other taxa all common. Conodonts (early planktonic vertebrates) appear.
|Cambrian ||Cambrian Explosion. Most modern animal phyla appear. First chordates appear, along with a number of extinct, problematic phyla. Trilobites, priapulid worms, sponges, inarticulate brachiopods, and numerous other animals. Anomalocarids are giant predators, while many Ediacaran fauna die out. ||541 |
|Ediacaran ||First multi-celled animals. |
Ediacaran biota flourish worldwide in seas. Possible worm-like Trichophycus. First sponges and trilobitomorphs.
|Cryogenian ||"Snowball Earth" ||720 |
|Tonian ||First simple multi-celled eukaryotes. ||1000 |
|Ectasian ||Green algae colonies in the seas. ||1600 |
|Statherian ||First complex single-celled life: protists with nuclei, Francevillian biota. ||2500 |
|Neoarchean ||Oxygenic photosynthesis first evolves. ||2800 |
|Mesoarchean ||First stromatolites (probably colonial cyanobacteria). Oldest macrofossils. ||3200 |
|Paleoarchean ||First known oxygen-producing bacteria. Oldest definitive microfossils. ||3600 |
|Eoarchean ||Simple single-celled life (probably bacteria and archaea). Oldest probable microfossils. The first life forms and self-replicating RNA molecules evolve. ||4000 |
|Indirect photosynthetic evidence of primordial life (e.g., kerogen). ||4130 |
|Nectarian ||First life on Earth. |
|Basin Groups ||End of the Early Bombardment Phase. |
Asteroids and comets bring water to Earth.
|Cryptic ||Formation of Moon (4,500 MYA), probably from giant impact. |
Formation of Earth (4,570 MYA), Early Bombardment Phase begins.
Formation of Sun (4,650 to 4,630 MYA).