The body is a complex thing made up of many parts. To understand its behaviour you have to apply the laws of physics to all its parts, not the whole. Behaviour is then an interaction off all the body parts. As the body is an interaction of parts it could not have come into being by one single act of chance. Different types of systems are really producing the same outcome, yet they may be using a different physical medium i.e. bats hearing and humans eyesight.
Evolution has therefore, many ways in developing good designs.
Thus,showing that the designr is unconscious, natural selection i.e. blind. Thing have evolved through natural selections natural stages. The time of these gradual stages is not known. Here would I be right in saying that because each step of evolution is so small changes could have arisen by chance. But the whole process is far too complex to be a chance occurance.