SPEAKER: This first member of our genus, Homo habilis, was discovered in the 1960s in East Africa. It was recognized that it did not fit easily into an australopithecine morphological pattern. For one thing, the cranial capacity was much larger, an average of about 610 cubic centimeters, well over 100 cubic centimeters than what we find in both the robust and the more gracile australopithecines. The teeth were smaller, and of course, considerable reduction of the canine tooth.
But you know, I think the most exciting thing about it was that it was found in direct association with stone tools. Yes, monkeys and apes today are known to use stone and other materials temporarily as tools. But the difference between a technology based upon stone tools, where you depend upon them for your survival, is a very significant difference. And it appears that Homo habilis, with stone tools of a particular tradition, used these, and their use enhanced the survival of that species.
These aren't stone tools that we would think of as very attractive. Essentially, they are river pebbles from which one end has been worked. And as these early tools were found with the fossils of Homo habilis in Olduvai Gorge in East Africa, they were called tools of the Oldowan Tradition, or more properly, pebble tools of the Oldowan Tradition. And we have a number of these in a number of different sites.
I don't think we can exclude the possibility that the australopithecines made tools. But we don't have good association of stone tools with Australopithecus, and we do with the first example of early Homo.
Now as early Homo evolved, it was able to export and open up new areas of habitation, perhaps to a more successful degree than even the gracile and robust australopithecines. There's an argument going on today whether Homo habilis is the whole story because in Kenya, to the South of where the habilines were found originally, is another group of fossils that look very similar to them, date to about the same period of 2.5 million years ago, but are much more robust.
And some paleoanthropologists would prefer to give them another species name. So rather than calling them Homo habilis, they would call them Homo rudolfensis. This is because they were found on the shores of Lake Rudolf in this other part of Africa. This debate continues. Certainly stone tools are found with Homo rudolfensis.
Taking the argument this far, then, it would seem that our genus originates either with Homo habilis and/or Homo rudolfensis. But there's a third possibility, and that is that we have another kind of Homo species evolving simultaneously, also in East Africa. This would be the species erectus, distinguishing it from habilis and rudolfensis.
Erectus, Homo erectus, is a very interesting group because not only do we find it in Africa, but we also find it in Southeast Asia and in China. It's possible, then, that out of the period of 2.5 million years ago, with the development of the first recognized stone tools and the evolution of Homo habilis and Homo rudolfensis, we have a third species evolving, Homo erectus.
Again, there's dispute about the name. Some of my colleagues prefer the term Homo ergaster rather than erectus. But certainly either term defines a group that is distinctive from habilis and rudolfensis.
In reconstructing the past and recognizing the importance of reconstructing behavior of our ancient ancestors, we're also dealing with advances in methodologies in both excavations and in dating. Excavation methods vary tremendously. At the Sterkfontein site in South Africa where australopithecine fossils have been found, the method to excavate is to blast with dynamite large chunks of the large cave section, and then carefully go through these and extract the fossils. In other situations, these dramatic efforts need not be followed.
But in every case the paleoanthropologist wishes to collect everything, not just the bones of the fossil, but also the artifacts, the archaeological associations, the fossil fauna, and everything that can be used to reconstruct the paleo environment.
Now from what I've said, one gets the impression that the whole business of paleoanthropology is finding more fossils. And granted, that's always welcome. But we could spend probably another generation just looking at the thousands of fossils we have and still make some progress in phylogeny and in other areas of interest to us.
But there's a broader interest than that, and that is the reconstruction of behavior of these early hominids. How did they live? What was their relationship to the arboreal environment? When did they leave the forest and survive out in a dry savanna environment with a different set of predators and a different set of stressors?
These are among the questions that paleoanthropologists ask. And the addition of more fossils-- all is welcome-- more often leads to the formulation of new questions, the disappearance of the sense of some old questions, and the reformulation of questions that had been asked for a long time but are now seen in a very different light.
We, as anatomically modern Homo sapiens, are very new. In fact, we find fossils of members of our own species, Homo sapiens sapiens, dating only to about 150,000 years ago. We're newcomers on the scene. This means, too, that the kinds of stressors which were the targets of natural selection for our ancestors are very different than the targets that we experience today.
And I would say that among those challenges of today are overpopulation, the threat of nuclear war, epidemic diseases, and a whole host of social changes that have affected our biology and raise the question as to whether we have adaptive strategies in order to survive these.
But perhaps what's most remarkable is that we, another kind of ape, have been able, over the last few centuries, to reconstruct our phylogenetic past and to use the methods of paleontology, geology, archaeology, anthropology to understand our origins and to have some insights as to the ways in which we can survive the future.
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Since the time of separation of the evolutionary lines of apes and humans about 5 million years ago, some fossil specimens of the skeletal remains of our earliest ancestors have been preserved and discovered. Putting together the pieces of the puzzle of human biological history is the task of paleontologists, geologists and anthropologists.
In this room we explore how these scientists can reconstruct the past from their studies of the geological contexts in which fossils are found, the dating of the specimens, their comparative anatomy with extinct and living species of our taxonomic order, the Primates, and the lifeways and behavior patterns of the first members of the human family within the Primates.
By looking at reproductions and pictures of this fossil record, including representations of pre-human Primate species, we learn about our prehistoric beginnings among those populations of first two million years of our evolution, as identified as Ardipithecus, Australopithecus and the earliest members assigned to our own genus- Homo habilis and Homo rudolfensis.
This video is part 13 of 13 in the Human Paleontology series.