Geology solar system

The History Of Life
Pre-cambrian (4600mya-540mya)

During this first period, life first appeared on Earth with a single celled bacteria which sometimes built pillow like colonies called stromatolites.  Later in the period primitive multicellular life appeared e.g. Jelly fish

Cambrian Period (540mya-490mya)

Evolution accelerated suddenly at the start of this period and complex life forms suchas trilobites which were the first creatures to see their world.  A giant shrimp called Anomalocaris was their main predator.

Ordovician Period (490mya-455mya)

Sea lillies first appeared during this period along with very often very large nautiloids closely related to modern squids which were the main predators of the time and trilobites were their main diet.  There was still no life on land.

Silurian Period (445mya-415mya)

In the sea, fish appeared for the first time, although most lacked proper jaws.  The land became colonised by primative plants for the first time during this period.  The main kind was called Cooksonia and was a few metres high.

Devonian Period (415mya-360mya)

Fish greatly diversified during this peropf and sharks appeared for the first time.  On land ther first small trees appeared and animal life, especially insects, started to become abundant.

Carboniferous Period (360mya-300mya)

During this period, there were dense forests of primitive looking trees over 40m tall and inhabited by giant insects and large predatory amphibians.

Permian Period (300mya-250mya)

Mammal like re