Millions of years ago in a valley in eastern Africa, there lived tribes of protohuman primates. At the time of initial contact with Transformers, there was little obvious external difference between the protohumans and other animals sharing their environment. But since the protohumans were destined to evolve into the modern human race, which would in turn play a key role in the Great War, these simple creatures were targeted for destruction by the time-travelling Predacons.
The Vok were aware of the existence and importance of the protohumans, since one of the relief images on the Alien Disk is a humanoid figure standing next to a tree. Precisely what their goals were for humanity is unknown. Beast Wars story editor Bob Forward later said that among the many unrealized ideas behind the Vok was the notion that they had put Earth's mysterious energon supplies there as a clean energy source to be used by eventual human descendants.
It is not possible to correlate the Beast Wars protohumans with any real prehistoric hominid. The era in which Beast Wars is set has varied wildly throughout different media, but for any of the purported time periods the level of physical and cultural advancements among the protohumans does not match what the fossil record actually shows. Megatron refers to them as "early anthropoids", Cheetor calls them "advanced anthropoids", and the script calls them "Neanderthals". At least no one called them "Leader-1".