Pattern in which physiological and behavioral systems evolve at different rates is called mosaic evolution.
ie A pattern of evolution in which the rate of evolution in one functional system varies from that in other systems. For example, in hominin evolution, the dental system, locomotor system, and neurological system (especially the brain) all evolved at markedly different rates.
Eg. Bipedalization and Encephalization , these traits evolved distinctly and separately with bipedalism preceding encephalization.