1. Theory of Special Creation According to this theory, all living things were created by God. This is considered as simply a religious concept, since it has no scientific basis
2. Theory of Catastrophism It says that since every creation of God has been always followed by a catastrophe, new creations after the catastrophe must be different from the last. This is considered as a modification of the theory of Special Creation.
3. Theory of Chemical Evolution According to this theory, living things are a result of a chemical evolution that happened 3.8 billion years ago.
4. Theory of Spontaneous Generation According to this theory, living things could sponatiously generate from non-living things through recipies. Helmont thought that rats could generate if you mixed dirty clothes with wheat.
5. Theory of Panspermia According to this theory, all living things came from a bacteria or spore that came with a meteorite.
