The Paleozoic era runs from 538.8 to 251.9 million years ago. It opens with the Cambrian explosion, when most major animal groups appear in the fossil record, and it sees the first fish, the first land plants and the first forests.
Vertebrates came onto land and the continents drew together into the supercontinent Pangaea before the end-Permian extinction, the largest mass extinction known, closed the era.
Explore this era on the timeline
Key events of the Paleozoic
26 events are on the timeline for this era; these are among the most notable, in date order.
- about 521 million years agoFirst trilobites
- about 518 million years agoFirst fish
- about 517 million years agoEnd-Botomian mass extinction
- about 485 million years agoCambrian–Ordovician extinction event
- about 470 million years agoFirst land plants
- from about 461 million years ago to 446 million years agoCaradoc
- from about 450 million years ago to 420 million years agoAndean-Saharan glaciation
- from about 449 million years ago to 444 million years agoAshgillian
- about 444 million years agoOrdovician–Silurian extinction event
- about 433 million years agoIreviken event
- about 428 million years agoFirst animals on land
- about 427 million years agoMulde event
- about 424 million years agoLau event
- about 385 million years agoFirst forests
- from about 380 million years ago to 280 million years agoVariscan orogeny
- about 375 million years agoFish with limbs begin to walk: tetrapods evolve
- about 372 million years agoLate Devonian extinction
- about 365 million years agoFour-legged vertebrates reach land
- from about 360 million years ago to 260 million years agoKaroo Ice Age
- about 359 million years agoHangenberg event
- about 335 million years agoSupercontinent Pangaea assembled
- about 320 million years agoFirst flying insects
- about 312 million years agoFirst egg-laying land vertebrates
- about 307 million years agoCarboniferous rainforest collapse
- about 273 million years agoOlson's Extinction
- about 259 million years agoMid-Permian extinction