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Cambrian Period 570-500M
570-500 Milion years. Most life during the Cambrian Period were aquatic, with trilobites as the dominant life form. -
Ordovician 500-435M
The Ordovician Period started at a major extinction event called the Cambrian–Ordovician extinction events. Trilobites and Brachiopods in particular were rich and diverse. -
Silurian 435-395M
Started when 60% of marine species wiped out by mass extinction. An evolutionary milestone during the Silurian was the appearance of jawed and bony fish. -
Devonian 395-345M
The first ray-finned and lobe-finned bony fish appeared. Placoderms began dominating almost every known aquatic environment. Primitive sharks became more numerous in the oceans -
Carboniferous 345-280M
Amphibians were the dominant land vertebrates, Arthropods were also very common. A small marine and terrestrial extinction occurred in the middle of the period. -
Permian 280-225M
World at the time had a large supercontinent called Pangaea. Trilobites and a host of other marine groups became extinct. About 90% of insects at the start of the Permian were cockroach-like insects -
Triassic 225-195M
Therapsids and archosaurs were the chief terrestrial vertebrates. Seed plants came to dominate the terrestrial flora. -
Jurassic 195-136M
Supercontinent Pangaea had begun rifting into two landmasses. Numerous turtles could be found in lakes and rivers. Large archosaurian reptiles remained dominant. -
Cretaceous 136-65M
Flowering plants spread during this period. Pterosaurs were common in the early and middle Cretaceous. Tyrannosaurus rex, one of the largest land predators of all time, lived during the late Cretaceous. -
Tertiary 65-1.8M
The first hominids appeared in Africa. Tropical plant species gave way to deciduous ones and grasslands replaced many forests. -
Quaternary 1.8-Present
Substantial glaciers advanced and retreated over much of North America and Europe. Giant mammals thrived in parts of North America and Eurasia. These mammals became extinct when the last Ice Age ended.
