Evolutionary adaptation in the earliest years of Earth is known to shape the formation of DNA genetic codes and cell formation. But if very long time , like billions of years passed, for the first cells to come into existance in an organic soup conditions of early earth, then pole bears should have come into existance during the ice age, in order to have copied the colour of snow, because in earlier times, ie in the time of Dinasours, the Earth had high and tropical temperatures , and this is prooven and well known by many Scientists. Then, how did evolution of a pole bear after death of dinasours, as soon as Earth entered the ice age, happened that quick? What factors enabled genetic code to be modified that quick, and most importantly, in that short time frame, how did pole bears become snow white in that very short time, compared to evolution of early cells in billions of years? Either cosmic rays or photon belt entry of our solar system accelerated the process, similar to what I proposed in my "Theory of Everything'', or there were maybe other factors leading to fast DNA chain formation and necessary genetic code to be formed that quick, which may have quickly triggered TAATA genetic code for life initiation for cells of the pole bear. What is that triggering factor for stressing such a complicated evolution in that short time? Especially Evolutionary Biologists, Quantum Chemists and Cosmic Scientists ; what do you think ?
It still involves natural selection as the conditions encountered by the bear were full of resources but extreme. This is the balancing act all creatures perform between environment and rich resources, or simply resources and environment that produce highest survival possibilities.
The Polar Bear is related to Brown Bears found extensively in North America, including Alaska and the wastes of Canada. If only a small number express variation, with degrees of white or lighter coloured fur this will improve their hunting efficiency compared to their dark brown or light brown cousins. The genes involved are selected.
This can be a seemingly rapid process if the costs of the environment are high.