Let’s imagine for a moment that you don’t know who your parents were. No records of them have been found yet. And because you don’t know your parents, you also don’t know for sure who your grandparents, great-grandparents or other direct ancestors were. But by some fluke you do know about some of your great-aunts and great-uncles, though none are alive now.
So you know about your general ancestry, where you came from, how your ancestors lived. But the family tree is complicated and you can’t be sure who your direct relatives were. You may be the offshoot of one of these aunts or uncle for all you know, you may be the result of a one-night fling or other scandalous pairing, or maybe your parents and grandparents just haven’t shown up in the records…yet.
Such a situation is where we stand with our species as a whole. We were “born” as a species when our bodies reached their present proportions about 195,000 years ago. Here’s a basic version of the family tree around us and just preceding us, with some species omitted. There isn’t complete agreement on it, and it keeps changing as new bones and DNA samples come in.
- Homo habilis (“handy man”) might be viewed as our great-great-grandfather (the masculine here will stand for both genders). He was good with tools and lived in Africa from 2.5 million years ago to 1.4 mya.
- His descendant or cousin, Homo ergaster (“working man,” even better with tools) lived at about the same time, 1.9 to 1.4 mya.
One of H. ergaster’s descendants was our grand uncle, Homo erectus, the first to stand tall and erect. Overlapping with our origins and a dominant presence in our past. H. erectus lived a long life not only in Africa but in Asia as well until 70,000 years ago. He used fire and he cooked. He lived in small, organized bands of families. He was thought to be our parent for a while but today the connection looks shaky.
- The strong contender for our immediate ancestor at present is Homo heidelbergensis, an offshoot of the handy man H. habilis. H. heidelbergensis lived about the same time that we appeared.
- Some H. heidelbergensis migrated into Europe where they evolved into the Neanderthals, our genealogical brothers or cousins. When we H. sapiens later migrated out of Africa, some of us lived near H. neanderthalensis, interbred with them (today almost all of us have a little Neanderthal in our genes), and survived them.
It’s a stunning story, all the more so because where we connect to it is still uncertain. The traits that we recognize as us—the abilities to walk and run, the skillful eye-hand coordination, the smarts to keep track of who to trust and who not to, our abilities both to exchange gossip and to discuss philosophy—all appeared step by step through such interesting early versions of us. And imagine being Homo erectus, with curiosity about how to chip a slightly sharper edge on your cutting stone or the skill to try out slightly different sounds as you talk to others. Or hearing the rumor that a group of men that look a little different than you, men who seem more organized and who carry longer spears, were appearing in the next valley.