1) Evaporation keeps the weather cycles going by evaporating the water from bodies of water (plants and animals) back up to produce clouds, which causes rain which falls back to the ground
2) Evaporation of perspiration from animals cools down their bodies to keep them from overheating.
3)Evaporation causes water to circulate up to the top of trees, so that every leaf gets nourishment, which puts oxygen back out into the air.
4)Evaporation causes liquids to dry, such as paint
These are just some of the things that Evaporation does