Earth history is divided into chunks of time, most importantly aeons, eras and periods. Dinosaurs and other prehistoric reptiles were the dominant animals for about 185 million years during the Mesozoic era, which was a section of the Phanerozoic aeon. More simply, the Mesozoic era lasted from 250 million years ago to 65 million years ago, and contained three periods called the Triassic, Jurassic and Cretaceous.
The first reptiles appeared during the Palaeozoic
Era (570 million to 245 million years ago), just before the
Mesozoic Era (245 million to 65 million years ago).
Each of these eras is divided up into sections called periods.
Palaeozaic era (say pall-ay-oh-zoh-ick)
Cambrian period: (570 million years ago)
The first fishes, corals, trilobites and shellfish appeared.
Right: Fossil trilobites
Ordovician period: (505 million years ago)
|The first nautiloids appeared. Corals and trilobites were common.||
A fossil nautiloid
Silurian period: (438 million years ago)
|The first land plants and giant sea scorpions called Eurypterids appeared.|
Devonian period: (408 million years ago)
|The first amphibians, insects and spiders appeared.||
Fossil of a plant called Archaeopteris from the Devonian period
|5. Carboniforous period: (360 million years ago)||The first reptiles appeared. Great swamp forests covered the land.||
Permian period: (286 million years ago)
|The first sailback reptiles such as Dimetrodon (right) appeared.||
|1. Triassic period: 245 million years ago||The first dinosaurs such as Coelophosis and Euskelosaurus, and mammals, turtles, crocodiles and frogs appeared.|
|2. Jurassic period: (208 million years ago)|| The first
birds appeared (e.g. Archaeopteryx).
Dinosaurs included diplodocus, stegasaurus, brachiosaurus.
|3. Cretaceous period: (144 million years ago)||Dinosaurs during this time included muttaburrasaurus, quetsalcoatlus, ankylosaurus. The dinosaurs died out towards the end of this period.The first snakes and modern mammals appeared.|
Click here to read a kidcyber page, 'Gondwanaland' about the drifting apart of the continents
Following the Mesozoic era was the Cenozoic (say sen-oh-zoh-ick) era (65 million to 0 million years ago), during which many different species of animals appeared. This era ended with the Great Ice Age and the appearance of the first humans.
Click here for a timeline with information about
Back to Animals
updated August 2006