Why do you see other colors in the fall

The cloriphile in the leaves/ thier is even some cloriphile in granite

When leaves die many plants get rid of their healthy "green" color.  Basically indicating that the leaves are currently not in use and the tree is ready to go "sleep" in the winter. If you live someplace where it's hot most of the year, you'll rarely see this effect. 

It is evolution, because we all have some of the same traits like eye color or shape or ears.