I find it every time enjoyable to see someone religious trying to explain why god exist.
Also, just as ACBeam mentioned, everything evolves to fit its environment. For example apes usually have longer and stronger arms than legs, that is because they
live surrounded by a lot of trees and using their arms to move from tree to tree is much quicker than walking on totally overgrown earth, plus most of what they eat is found on trees as well. I'd also say the fact that animals like pumas or snakes that usually live on the ground try to kill and eat them is an important factor as well.
http://www.infoplease.com/dk/encyclopedia/evolution.html
On there it is explained how new species evolve, like us humans from monkey's but still having our ancestors today and how long evolution can take.