Anthropology Professor Adrienne Zihlman presents the similarities between the skeletons of male and female pygmy chimpanzees as an example of how difficult it can be to determine the sex of the fossilized remains of early human-like species.
Is it a natural characteristic of life on Earth to be self-destructive? Tim Flannery, author of Here on Earth, argues against Peter Ward's "Medea Hypothesis," which proposes that multicultural life is inherently suicidal.
Professor Donald Johanson, the paleoanthropologist responsible for unearthing the first known remains of Australopithecus afarensis, describes how his discovery ended up with the name "Lucy." Johanson explains that what started out as an off-the-cuff suggestion, ended up securing the fossil a place in popular culture.
Ian Tattersall, paleoanthropologist and curator at the American Museum of Natural History, describes the discovery of the LB1 bones (nicknamed the "hobbit"), and the mystery surrounding the nearly complete skeleton.
Evolutionary biologist Richard Dawkins explains a thought experiment imagining every generation of a single ancestor back millions of years. He argues that because of the gradual process of evolution, there was no single point when Homo erectus became Homo sapiens.
Neurologist Robert Sapolsky explores the genetic differences between humans and chimps, and describes the few genes that make our species unique. Our two species share over ninety-eight percent of the same genes, with only one major trait separating us from other primates: an abundance of neurons.
"Take a chimp brain fetally and let it go two or three more rounds of division and you get a human brain instead," says Sapolsky. "And, out come symphonies, ideologies and hopscotch."