You will need to log in to book media
Part 1: The First Hunter - The first animal to develop a head, eyes and a brain also pioneered a new way to survive: it would become Earth's first hunter. Dramatic new evidence points to an unlikely and oddly charismatic subject...the flatworm. Part 2: Explosion of Life: According to fossil evidence, it appears as if in one dramatic moment -- the Cambrian Explosion, an amazing menagerie of animals suddenly appeared on Earth. What animals appeared? What caused this sudden proliferation of life? Surprisingly, one of the least suspecting and simplest of these new life forms -- the annelid worms -- would help shape the world we know today.