Millions of years before present
Modern bivalves and gastropods appear and radiate. Early mammals.
Brachiopods decline. Radiation of insect orders associated with flowering plants. Ended in a mass extinction.
Brachiopods, corals, and marine bivalves common. South America and Africa separate, and Atlantic Ocean is born.
Increase in diversity of marine invertebrates. First flies and sawflies. First dinosaurs.
Insect diversification on land and in freshwater, first records of beetles. All continents joined together to form a single landmass. Ended with a mass extinction of 90% marine invertebrates, especially those living in shallow waters, all Trilobites became extinct, and 75% of land species became extinct.
Insects colonise land. Giant dragonflies. Corals and brachiopods abundant. British climate is equatorial.
Bryozoans, corals and brachiopods abundant. First evidence of scorpions. Europe collides with N. America and Greenland.
Marine invertebrates abundant. Trilobites declining. Spread of molluscs. Armoured fish. The Ordovician ended in a mass extinction.
Origin of many invertebrate phyla. Trilobites dominant. Earliest crustaceans. Small molluscs. Britain and Europe in the southern hemisphere.
Animal fossil evidence rare; evidence of sponges, cnidaria, ctenophora, and worm burrows c. 670-570 MYBP. Anaerobic bacteria about 3800 MYBP.