P200 Introduction to Prehistoric Archaeology
Evolutionary Context for the Oldest Archaeology
Part I: the early australopithecines
During the twentieth century, anthropologists have found and described a wonderful collection of fossil bones from human ancestors, and their relatives that demonstrate dramatically and conclusively that Africa was the original human home.
Members of the human family Hominidae are called hominids. The earliest hominids known so far have been found by Drs Tim White and Berhane Asfaw in Ethiopia, from a series of deposits in the northern end of the Great Rift Valley, and are estimated to be around 5 million years old.
Note how "bushy" this hominid family tree is -- this is because after the firs hominids appeared around ~5 million years ago, they began to diversify into different lineages (branches of the family tree), specializing in different ecological niches.
They also probably evolved separately in eastern and southern Africa, as all species separated by geographical barriers will eventually do.
The earliest hominids were small, ape-like "bipeds" (walked on 2 legs), called australopithecines. As described in your textbook, their bipedal footprints have been found at a site in East Africa (in Tanzania) called Laetoli.
The australopithecines were first named by Raymond Dart, who described a juvenile skull of the first one in 1924. He named his specimen Australopithecus africanus, ("southern ape-man from Africa") and thought it had both human characteristics (small canine teeth and bipedal gait) and ape-like characteristics (small brain, projecting snout).
For many years, most famous australopithecine was a partial skeleton of a small female Australopithecus afarensis that lived around 3 million years ago in Ethiopia, called "Lucy."
There is still considerable disagreement about which of the closely related sister species, Australopithecus afarensis or Australopithecus africanus, was most likely to be our direct ancestor. The first members of our own genus, Homo, don't appear until ~2.5 million years ago.
A new discovery of a skeleton in a cave deposit at the site of Sterkfontein, South Africa, may become even more famous than Lucy, because the skeleton is almost complete! The most recent major find was announced in December 1998 -- a COMPLETE skeleton of an australopithecine from the South African site of Sterkfontein, discovered by Ron Clarke and colleagues. It is just now being excavated from the wall of a cave deposit over 3 million years old, making it a southern African contemporary of east African Lucy.
Refer to the BBC online report for some of the details. See MAP of site locations. It looks like this skeleton will be assigned to the species Australopithecus africanus, the first hominid juvenile specimen described by Raymond Dart in 1924.
So, did these early australopithecines have an archaeological record?
Were they cultural animals? Did they create and use tools, or have a "material culture" that we can recognize? Raymond Dart thought so! He thought that the broken bones, the sharp teeth and horns associated with australopithecus africanus fossils in South African cave sites represented tools and weapons used by these hominids -- he called it the "Osteo-donto-keratic" culture -- and argued that they were our blood-thirsty, violent ancestors, and that the skills they acquired to capture game led to the evolution of increased intelligence in humans.
But are we sure? Let's be skeptical archaeologists. Read some STUDENT COMMENTARY on this question.
- What criteria can we use to decide if these were really "artifacts" used for hunting & butchery?
- definite evidence of hominid manufacture or use
- association with hominid fossils is causal, not circumstantial
- other evidence that hominids ate meat
- What alternative explanations can you think of? (Read about bob Brain's hypotheses in your book.)
- coincidental association in cave deposit
- "tools" formed naturally (e.g. through carnivore chewing)
- bones accumulated from carnivore meals
- hominids didn't live in caves, they just died there.
- Read about the latest Australopithecine fossil discovery in Ethiopia, Australopithecus garhi
- Refer to my more detailed online lecture notes about early hominids from my 1997 A105 class
- Read a brief history of earlier discoveries at the Sterkfontein Valley cavesites from the University of Witwatersrand, South Africa.
- Link to a recent CNN story about new evidence for early australopithecine diet.