I was thinking about Europa today and considering how life might exist on it. Spacecraft and models have shown that all of the ingredients for life is there, but I was wondering about the evolution of life after it forms. Earth had a lot of very diverse environments, which greatly accelerated evolution. It has hot water, cold water, mineral rich water, mineral lacking water, acidic areas, UV saturated areas... How many different environments would exist underneath the oceans of Europa? I'm sure that closer to the surface would be colder and less nutrient rich than the deep ocean, but how much so? Would the poles be different than the equator?