@fooflexible
Well if you have read books on evolution you have misinterpreted it. Evolution is not chance. Chance is something that happens randomly. If say over a very long period of time the world slowly got colder. Now lets take a short haired mammal living in a hot enviroment, say a Tiger. Every Tiger has a different length of hair determined by a gene. Now as the environment slowly gets colder, the Tigers with the longest hair are more likely to survive, so are more likely to produce offspring and therefore pass on their 'longer hair' gene. Over time as the environment gets colder and the 'longer hair' gene gets passed down generation to generation, slowly the Tigers hair gets longer an longer with each generation. Say this time period was 1,000 years. So you take a Tiger from a hot environment and see that it has short hair, perfectly evolved to the hot environment. Then 1,000 years later you take a longer haired Tiger, perfectly evolved to its colder environment.
This is evolution, I hope you can now see that the Tiger didn't randomly, by chance grow longer hair. But rather the Tigers that had shorter hair froze to death in the colder environment, and the longer haired Tigers survived, passing on their 'longer hair' gene.
You have to remember that evolution doesn't think or have a will, a slug isn't any less evolved than a Human and a slug wont evolve into a Human. Evolution doesn't have a goal or an aim. It just explains how animals are perfectly adapted to their environment.
