Walking for Sex

Johanson Readies for Next Big Paleontological Mêlée

One of the most accomplished scholars of human origins, Dr. Donald Johanson, the producer of one of the field’s most groundbreaking discoveries: the 3.2-million-year-old skeleton called Lucy dazzled a 400 person packed Gilbert H. Grosvenor Auditorium at National Geographic Society last evening in Washington DC.

His speech was coincident with the celebration of Charles Darwin’s Origin of the Species.

Johanson took the audience on a tour of his paleontological life that began when he was 13 years old. An orphan, his mentor guardian had a large library collection and in it he discovered a well-illustrated book of paleontology. It was adjacent the Origin of the Species, though he was more attracted to the illustrations than the heavier writing from Darwin.

From hunching to upright walking, he explained the history of the discovery of humans in Africa and the controversy circling other claims and theories that fell apart when science intervened.

The news of the evening came when he addressed the October 2009 cover story of Science journal in which Berkeley paleontologists introduced “ardi,” an alleged hominid that is 1 million years older than Lucy. Johanson doesn’t buy it. He will take up the debate in earnest in the spring.

Tip: The sexy part of the story is in the National Geo link.

YJ

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“Ardi's Secret: Did Early Humans Start Walking for Sex?

Jamie Shreeve
Science editor, National Geographic magazine

October 1, 2009

The big news from the journal Science today is the discovery of the oldest human skeleton—a small-brained, 110-pound (50-kilogram) female of the species Ardipithecus ramidus, nicknamed "Ardi." She lived in what is now Ethiopia 4.4 million years ago, which makes her over a million years older than the famous Lucy fossil, found in the same region 35 years ago.

Buried among the slew of papers about the new find is one about the creature's sex life. It makes fascinating reading, especially if you like learning why human females don't know when they are ovulating, and men lack the clacker-sized testicles and bristly penises sported by chimpanzees.

(See pictures of Ardipithecus ramidus.)

One of the defining attributes of Lucy and all other hominids—members of our evolutionary lineage, including ourselves—is that they walk upright on two legs. While Ardi also walked on two legs on the ground, the species also clambered about on four legs in the trees. Ardi thus offers a fascinating glimpse of an ape caught in the act of becoming human. (Interactive: Ardi's key features.)

The problem is it is doing it in the wrong place at the wrong time—at least according to conventional wisdom, which says our kind first stood up on two legs when they moved out of the forest and onto open savanna grasslands. At the time Ardi lived, her environment was a woodland, much cooler and wetter than the desert there today.

So why did her species become bipedal while it was still living partly in the trees, especially since walking on two legs is a much less efficient way of getting about? “

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