"The second law of thermodynamics says that order cannot come from chaos, so how can complex beings come from simple ones"
This shows a misunderstanding of the second law of thermodynamics, which says that 'Entropy (disorder) in a closed system must always increase'. Do you see the problem yet?
That's right - the Earth is not a closed system. It gets additional energy from the sun, so the second law of thermodynamics doesn't have to apply to it (it does apply to the universe, being a closed system).
--Thomas
