Who were our ancestors?
Imagine you get together with your grandmother and invite her to visit an empty stadium with capacity for 60,000 spectators. You sit next to your grandma. Next to her sits her grandmother: your great-great-grandmother. Again, next to your great-great-grandmother sits her grandmother. And so on. Until we fill the whole stadium.
After 59,999 women have arrived, the last individual is an ancestor of all the others, who no longer resembles either you or your close relatives.
She is an australopithecine, a relative of the Australopithecus afarensis, small in size and with long arms, which can hang from the ceiling and swing from one beam to the other to go and steal peanuts from the vendors. Three million years and 120 thousand generations separate you from her. She lived in Africa and is a close relative of the famous Lucy. Most of her contemporaries disappeared, leaving no offspring, but she was one of the few lucky whose genes survive.
If we repeat this experiment with her entering the stadium first and filling the stadium with her grandmother, her grandmother’s grandmother, etc., we would reach our ancestor of 6 million years and 240 thousand generations ago. That ancestor is a contemporary and close relative of the common ancestor of humans and chimpanzees. She is probably more similar to a chimpanzee than to a human.