We used to think that humans evolved from chimpanzees in an elegant, simple lineage where one hominid species evolved into the next, with few species living together on the planet at the same time. In 1924, when the Taung child was found, we thought that Australopithecus was the same. However, as more fossils have been found, they have been named either Australopithecus africanus or Paranthropus robustus by the exact site they were found at, with little attention paid to what these fossils actually look like or question as to why Paranthropus died in one valley, while all Australopithecus died in a different location only a short walk away.
This audioslide show goes through our discovery of Australopithecus africanus, starting at the Taung child. AAAS member Jeffrey Schwartz, professor in the Departments of Anthropology and History and Philosophy of Science at the University of Pittsburgh, has spent much of his career studying the human fossil record and how we evolved from primates into humans. He points out the similarities between several examples of both Australopithecus africanus and Paranthropus robustus, and questions the designation between the two. He also shows several fossils found in East Africa that were dated to the same time period as the Taung child, and he questions whether they actually belong to a similar species as well.
Schwartz is the author of a number of books including: Sudden Origins: Fossils, Genes, and the Emergence of Species, Extinct Humans, The Human Fossil Record, Volume One: Terminology and Craniodental Morphology of Genus Homo (Europe), The Human Fossil Record, Volume Two: Craniodental Morphology of Genus Homo (Africa and Asia), The Red Ape: Orangutans and Human Origins, The Human Fossil Record, Volume Four: Craniodental Morphology of Australopithecus, Paranthropus, and Orrorin, and Skeleton Keys an introduction to human skeletal morphology, development, and analysis.
Also check out Jeff Schwartz's previous audio slideshows: The differences between Neanderthals and Homo sapiens, Homo Erectus and the idea that fossils from that time might also be from many different species.