Conclusion
The most important point to make about the story of human evolution is that we have not yet written it. We thought we had: by the late 1990s anthropologists were converging on a story. But the flurry of new discoveries since 2000 – not just from fossils but from DNA evidence, too – has thrown the story into confusion.
It is too soon to tell how all the new pieces of the puzzle will fit together. But here is an interesting speculation to end on: what if the history of palaeoanthropology had been reversed? In other words, suppose Homo naledi and Australopithecus sediba – the two species discovered most recently – had in fact been discovered decades ago, with ‘classic’ species like Homo erectus and the Neanderthals being uncovered only in the last decade.
If all we had had to go on for decades were H. naledi and A. sediba, it seems likely that our ideas about human evolution would have been very different. We would surely have assumed that our species originated in southern Africa, rather than East Africa as was long thought. Faced with ‘new and strange’ discoveries like H. erectus, we would find ourselves thoroughly confused.
It seems virtually certain that there are more species to be found – perhaps many more. DNA will continue to reveal more about how and when our species’ traits appeared. And the picture will keep changing. Unlike some branches of science, human evolution has not yet figured out its central message.