The Cretaceous Period was a time of great change for the Earth. The climate warmed, the continents moved and new life forms appeared. The Cretaceous is best known for its dinosaurs, but many other types of animals and plants flourished during this time.
The Cretaceous began 145 million years ago and lasted for 80 million years. It followed the Jurassic Period and was succeeded by the Paleogene Period. The Cretaceous was a time of great change on Earth. The continents continued to move as they do today, but at a faster rate. This resulted in changes in climate as well as the habitats available for plants and animals.
New types of plants appeared during the Cretaceous, including flowering plants (angiosperms). These were very different from the earlier gymnosperms, which did not produce flowers or fruit. Angiosperms eventually came to dominate the land ecosystems. Some dinosaurs ate angiosperms, while others specialized in eating gymnosperms.
The first birds appeared during the early Cretaceous period, although they were very different from modern birds. Birds evolved from a group of reptiles called archosaurs. Archosaurs included crocodiles, alligators, and dinosaurs such as Tyrannosaurus rex and Velociraptor. Some archosaurs had feathers, but it is unclear if these were used for flight or insulation. By the end of the Cretaceous period, most archosaurs were extinct due to competition from birds or changes in climate/vegetation.. Modern birds are descendants of a group of feathered archosaurs called maniraptors