Whenever and among whomever toolmaking arose, it came long after the transition from a tree-based locomotion style to the upright-walking stance that freed the hands, which took place at least 4 million years ago and possibly as far back as 6 million years ago. It took considerable change in the hands and fingers to create the deft manipulative abilities of the Homo species. Major changes show up in the fossil record of the species known as Homo habilis, or "handy man." These individuals had a mobile thumb joint, powerful muscles to bend the fingers, and large fingertips -- all adaptations that may have made possible the making and use of stone tools, and came just as the human brain was expanding and undergoing reorganization.
Once tool manufacture and use became an essential component of the human lifestyle, affecting the amount and quality of food an individual could obtain, tool use may have driven the further evolution of the human hand. Individuals whose hands happened to be better adapted for tool use would tend to be better nourished and to successfully raise more children, who in turn would be likely to inherit their parents' hand morphology.
Thus our ancestors' manipulative abilities increased, until the modern human capacities of grasping and manipulating, which allow us to throw a curve ball or play a symphony, were much as they are today.
