The Triassic is a geological period and system that spans approximately 250 to 200 million years.
The Triassic marks the beginning of the Mesozoic (secondary era). The dinosaurs begin to develop. They are smaller than their Jurassic and Cretaceous descendants.
The continents form a single block, which scientists call Pangea, which means "all the earth".
Other groups include aquatic reptiles and flying reptiles. There are still reptiles from the Permian, called "mammalians". On the plant side, coniferous trees take their place.