Becoming Human

By examining patterns of DNA variation in the genome for different human populations, we can determine how much of our evolutionary history was influenced by simple demographic change or, alternatively, by spurts of natural selection.

Teaser: Human offspring take more than twice the time to reach adulthood than do our closest living relatives, chimps and gorillas. This period of delayed maturation results in what we call the teenage years and is a characteristic of modern humans. Paleoanthropologists wonder how far back in the record of bipedal existence this delayed maturation commenced.

Dr Gary Schwartz, professor of paleoanthropology at the Institute of Human Origins, Arizona State University, is researching fossil teeth at the micron level and discovering what several million year old teeth can tell us about the individual whose teeth they were and how rapidly our earliest ancestors matured to adulthood as compared with other great apes.

Evidence of early humans living on the coast in South Africa, harvesting food from the sea, employing complex bladelet tools and using red pigments in symbolic behavior 164,000 years ago, far earlier than previously documented, is being reported in the Oct. 18, 2007 issue of the journal Nature.

In a paper appearing on September 20 in Science, analysis of the wrist bones of Homo floresiensis demonstrates this skeleton could not be a dwarf human, as has been argued. The paper also adds to the accumulating evidence the specimen is a strange mix of nearly modern and very primitive characteristics.

The suggestion interbreeding occurred between Neanderthals and Homo sapiens nearly 40,000 years ago, announced in papers published last November in both Science and Nature, has now been called into question.

Fossils from Kenya, with implications on the relationship between Homo habilis and Homo erectus, and uncovered in the year 2000, wee announced in a letter appearing in the August 9. 2007 issue of Nature. The authors, F. E. Spoor, M. G. Leakey et al.

The Child from Dikika

"The Origin of Species" is almost 150 — a fit survivor of the science canon even if not everyone has seen fit to jump from the Ark to the Beagle on the matter of evolution (three Republican presidential candidates, for example). But Darwin himself was slow to come to his ideas, and slower still to disclose them to a skeptical public.

Noted leader in the field of human origins research dies Dr. Howell led or participated in fossil-hunting excavations around the world, in Turkey, Spain and China, as well as Ethiopia, Kenya, South Africa and Tanzania.