A Bipedal Ancestor? Ardi's opposable big toes and walking habits were a recurring theme in today's chat on ScienceNOW's Facebook page.

C. O. Lovejoy et al., Science

Facebook Chat About "Ardi" With Science Correspondents

Do humans and chimps share a common ancestor? Why did Ardipithecus ramidus, the newly unveiled early hominin, have opposable big toes? Yesterday, ScienceNOW asked our followers on Facebook to submit their own questions about "Ardi" to Science reporter Ann Gibbons and editor Elizabeth Culotta. Today, Ann and Elizabeth answered the questions in a live Q&A session while enthusiastic readers logged on to hear about this remarkable new chapter in the story of human evolution.

The questions ranged from the general ("Why is Ardi's discovery so important?") to the very specific ("Was Ardi a brachiator?"), and some queries inspired recurring discussion throughout the 2-hour session ("How did Ardi--and humans--become bipedal?").

ScienceNOW thanks Ann and Elizabeth for lending their time and expertise today, as well as our followers on Facebook for providing such thought-provoking questions.

For a full transcript of the chat, see part one and part two on ScienceNOW's Facebook forums.