The Cretaceous Period is the period of time from about 140 million to 65 million years ago (ages vary). Associated with it are warmer global temperatures and no major glaciers, which enabled the survival of large reptile dinosaurs, such as the Tyrannosaurus rex. It is also the time of the appearance of modern insects, flowering plants, and new mammal species.
Period | Millions of Years Ago |
Life Forms | |
Ceneozoic | Quaternary | 1.8 | Man, mammals |
Neogene | 24-1.8 | First hominids, horses, canine | |
Paleogene | 65-24 | tapirs, rodents | |
Mesozoic | Cretaceous | 146-65 | marine invertebrates, marsupials, pterosaurs |
Jurassic | 208-146 | Suaropods, birds, flowering plants | |
Triassic | 248-248 | First mammals, turtles, ichtyosaur | |
Paleozoic | Permian | 280-248 | Amphibians and reptiles |
Pennsylvanian | 325-280 | First reptiles, ferns, cockroaches | |
Mississippian | 360-325 | First-winged insects | |
Devonian | 408-360 | Fish and land plants | |
Silurian | 438-408 | First-jawed fishes, first insects | |
Ordovician | 505-438 | First-primitive plants, corals, fungi | |
Cambrian | 575-500 | Trilobites, mollusks, brachiopods |