4. Evolution works through mutation.
Errrrgghh... I disagree with Stephen Hawking. Ok, mutation helps, but you know what? Evolution doesn't need it. Most mutations result in a f*kup, not something useful. Evolution just needs seperate populations and/or environments. Eventually populations diverge and become more suited to their environments.
I feel weird....
Not only are you weird you are wrong on this point, though you were more or less right
on your first three. Evolution operates on variation. The ultimate source of variation is mutation. The fundamental source of mutation is radiation and other events at a quantum mechanical level. Therefore evolution is stochastic. Without mutation while their could be some limited evolution by genetic rearrangements, however there could no longer be any evolution of proteins which is the real driver of evolutionary change.
Does that explain it simply enough.
Unix is the worst operating system; except for all others. -- Berry Kercheval