What are the periods of life on earth broken into?

1 Answer
Aug 16, 2016

Earliest cellular life on earth evolved about 3.5 billion years ago during precambrian time from protobionts/coacervates. Life then amazingly diversified through natural selection till recently.


**Geological history of earth is studied by dividing it in eons, then further dividing eons in eras, era in periods, period in epochs. Life appeared in Archaeozoic eon. Multicellular life appeared during Proterozoic eon. Currently it is Phanerozoic eon, that started about 540 million years ago.
The Phanerozoic eon is divided in three eras: Palaeozoic, Mesozoic and Coenozoic. There are 11 periods under these three eras, the first being Cambrian.
(That will explain the term precambrian that I used earlier.)

**The 11 periods are Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian (all under Palaeozoic); Triassic, Jurassic, Cretaceous (under Mesozoic); Tertiary and Quaternary (under Coenozoic).

Tertiary and Quaternary are divided in Epochs: Palaeocoene, Eocoene, Oligocoene, Miocoene, Pliocoene and Pleistocoene, Holocoene.**

To know more on this, you must phrase key words as ' Geological Time Scale ' and search the net. It is an interesting topic.