The very definition of species implies that two totally different species can not produce fertile offspring, if the offspring is infertile, then that lineage has no future. Evolution is just not random anymore than the course of a river is random. Rivers programs are based mostly on a number of components, the slope of the terrain, the speed and ease at which the soil erodes, the precise make-up of the water itself, and many others.. Setting additionally has an amazing deal to do with evolution, that is why you do not discover thin-skinned amphibians within the desert, or water respiratory mammals, or arboreal crabs. Species that develop traits that profit them of their setting survive, traits that hinder them result in their extinction. Generally totally different populations of the identical species finally ends up taking two totally different evolutionary paths which make the hole between their descendants develop wider and wider over time. I might say it is various, I’d even say chaotic, however random? By no means.