Purpose of evolution is survival, different species evolve in different ways because it serves their survival interests, for example animals that become household pets end up losing many abilities like hunting skills, become dumber in many ways, yet adapt and learn emotional intelligence from humans as well as speech recognition and other qualities. Animals farmed for food becomes less intelligent than the ones in wilderness, because they are fed and sheltered and only need to grow faster to genetically survive and used to produce the next generation. Many rodents and insects on the other hand became more advanced trying to survive alongside humans that seek to exterminate them. In other words, evolution can go both ways, depending on the species and the circumstances, that's how we have such diversity