Early Ideas
Great Chain of Being Plotinus (270 BC - 205?)
The idea that all thing formed a hierarchy
God
Angels
Man
Animals
Plants
Dust
Spontaneous Generation
Life arises out of mud, and decayed meat.
Photo credits:
http://www.attan.com/start.html
http://www.newworldencyclopedia.org/entry/Great_Chain_of_Being