I found the following quote from a paper I dug up on the Net, “A paleontological perspective on the evolution of human diet, ” Peter Ungar and Mark Teaford at a symposium at the University of Arkansas,(1) while searching for data on gorilla and chimp fossils. There were a lot of interesting papers at the conference including one by the suddenly ubiquitous Richard Wrangham. Anyway, Pete and Mark had this to say:
“Investigators have tried to relate patterns of hominid evolution with patterns of climatic change for some time (see for example Potts 1996 and Vrba 1995). The focus of recent work has been on the origin of the genus Homo. Can the dietary shifts in the earliest hominids be tied to such changes? While there is some evidence of large-scale climatic changes around the Mediterranean (Bernor, 1983) and unusual faunal turnover in parts of western Asia ( Barry 1995), there are no large-scale changes evident in sub-Saharan Africa until after the earliest hominids have come and gone (1.5 - 2.5 Ma). There is the slow and inexorable cooling and drying of the Miocene, but perhaps the crucial resultant of that is the increase in microhabitat variability. In other words, after Ardipithecus, the early hominids are almost always found in lake and river margin habitats, often in the vicinity of a mixture of woodland and bushland and even grassland. In such a land of variable opportunities, the generalized craniodental tool kit of the very earliest hominids may have had a distinct advantage.”
I’d particularly like to point out the final sentences: “…the early hominids are almost always found in lake and river margin habitats, often in the vicinity of a mixture of woodland and bushland and even grassland. In such a land of variable opportunities, the generalized craniodental tool kit of the very earliest hominids may have had a distinct advantage.”
I’ll have to take their word on craniodental tool kit, but I’d like to believe it’s true. I focus on those “lake and river margin habitats.” Those marginal habits provide, as the authors noted, “a land of variable opportunities.” That’s what I learned as the “edge effect,” fifty years ago. Glad to see it’s making a revival; the margins are where the biomass is. The edge does have, indeed, variable opportunities.
Likewise, it’s always nice to see the fluvial/lacustrine deposition of most hominin fossils being recognized; the savannistas always consider that an incidental fact. Like duck bones down at the river being incidental. Or fish, maybe. The authors didn’t comment on where one finds most fossil gorilla/chimp bones although there’s an implication that hominid bones are found in a specialized location. In any case, except for the terminology, that quote could have come from myself, were I a technical writer. (Which I’m not, or I couldn’t throw in asides like this.) All I can say is that, if you draw a line from those hominid fossil locations to our current demography, you’ll note it goes straight and solves at one fell swoop many of the mysteries of human evolution and expansion.
One last reminder:
The knot. I bring this up now and again: the ignored invention that revolutionized the world as much as capturing fire. If you haven’t thought about when the knot was invented, you might. For some reason, I’ve been unable to find any discussion of the knot in scientific circles; it doesn’t seem to be a topic that excites paleoanthropologists. The fact that you can’t find fossil knots certainly contributes to that, but that shouldn’t mean that the knot shouldn’t be considered when considering the cultural evolution of humans and their expansions. (I did run across one website that said knots were discovered, not invented, which I thought an interesting and slippery distinction. Where do discoveries stop and inventions start?) And again, the day after you figured out knots, you had rafts. Providing, of course, you were living down by the water. Which we were.
5 years ago