The ancestors of humans diverged from monkeys about three million years ago. I found it interesting to find that according to another Wikipedia site there were three or four other species that diverged from monkeys as well and are in the same subtribe but only humans exist of their ancestors. It could be thought that all the subtribes eventually mated into one subspecies, but I found no research suggesting that or what happened to those species. However, I did find information on how humans likely developed.
Apes travel in packs, though generally loose ones. They live in forests and are designed for moving about in the trees. Somewhere in our history our ancestors moved out of the forests to begin standing on two feet and they moved away from the plentiful forests. (That could be a byproduct of the Ice Age if their forests disappeared or didn’t produce enough food for the whole family.) Once out of the trees it was faster for the large apes to move and run on two legs than the uneven four legs so they became bipeds, as we are today. They also decided, somehow, that it was best to have a single location everyone congregated, or a camp. From there the apes could travel out to find food each day, mostly plants, and return to divide the food found among the whole camp, not just themselves as most apes do. The camps allowed for safety in numbers as well as somewhere to return. While the females went to pick and dig up plants while caring for or carrying their young, the more mobile males went hunting for animals farther away. When they came back they shared their meat with the camp and the days they brought nothing back they ate what the females and children had found that day. Eventually as the camp grew more meat was needed and they started hunting bigger animals and figured out tools to help them. Meanwhile the females were likely realizing that where small pieces of plants (seeds) fell, new plants grew and started to plant things so they wouldn’t have to journey so far each day. But I’m getting ahead of myself.