Timeline of Prehistoric Eras
Prehistoric reptiles, including dinosaurs, were the dominant animals for about 160 million years.This 160 million years is divided into two sections, called eras.

They are the:
Palaeozoic Era (570 million to 245 million years ago)
Mesozoic Era (245 million to 65 million years ago).
Each of these eras is divided up into sections called periods.

Palaeozaic era (say pal-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.


Mesozaic era (say mezo-zay-ick)

 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.  

All through this time the earth was changing.
In the
Triassic period, all the continents were joined together in one huge landmass. Climate was hot and dry but with rain seasons. The first tree ferns and coniferous trees were starting to appear.

In the
Jurassic period the climate changed as the huge continent was breaking up. There were now forests of cycads, conifers and gingko, all plants that still exist today.

In the
Cretaceous period the continents had separated and each had its own flora and fauna. There were now flowering plants such as magnolias and waterlilies.However, Australia and Antarctica were still joined together.

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.

Go here for a timeline with information about each era

If you use any part of this, acknowledge it in your bibliography like this:
Sydenham, S. & Thomas, R. A Timeline of Prehistoric Eras [Online], Available: www.kidcyber.com.au(2002).

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updated October 2013©www.kidcyber.com.au