How does the creation of a new mountain range in an ecosystem affect an animal population that becomes divided into two groups by the mountains?

Over time the two groups of animals with evolve different features that are suitable in their environments and eventually won’t be able to mate with each other at all.

emerging idea only occurs as a raw idea that could appear out of nowhere. meanwhile, to reach scientific consensus , that idea must be structured and tested over and over again through various experiments. the scientific consensus transforms the raw idea into idea that is more reliable through the process of scientific elimination.