The great periods

The Permian precedes the Triassic and belongs to the Palaeozoic. Dimetrodon lived during this period: this synapsid is more closely related to mammals than to dinosaurs. The Permian ended with a mass extinction about 252 million years ago.

Most land forms Pangaea, a vast supercontinent surrounded by the Panthalassa ocean. The climate is generally warm, with extensive dry regions.

Life diversifies again after the end-Permian crisis. The first dinosaurs, pterosaurs and mammals appear during the Triassic. Another major extinction marks its end.

Pangaea breaks apart. New oceans reshape the world, while shallow seas cover parts of Europe.

Dinosaurs are prominent on land. Giant sauropods live alongside predatory theropods, and the first birds appear. The Jurassic lies between the Triassic and the Cretaceous.

Continents continue to separate and sea levels are high. Flowering plants spread and diversify.

This is the final period of the Mesozoic. It ends with a mass extinction associated notably with the Chicxulub impact: non-avian dinosaurs disappear, but birds survive.

The Paleogene begins the Cenozoic after the end-Cretaceous extinction. It spans 66 to 23 million years ago and includes the Paleocene, Eocene and Oligocene.

Mammals and birds diversify and occupy many ecological niches. Non-avian dinosaurs have disappeared, but their avian lineage continues through birds.