Dolphins are one of the smartest animal species on Earth. In fact, their encephalization quotient (their brain size compared to the average for their body size) is second only to humans. But exactly how smart are they? Lori Marino details some incredible facts about dolphins.
The episode begins in the South American rainforest whose rich variety of life forms is used to illustrate the sheer number of different species. Since many are dependent on others for food or means of reproduction, David Attenborough argues that they couldn't all have appeared at once. He sets out to discover which came first, and the reasons for such diversity. He starts by explaining the theories of Charles Darwin and the process of natural selection, using the giant tortoises of the Galapagos Islands (where Darwin voyaged on HMS Beagle) as an example. Fossils provide evidence of the earliest life, and Attenborough travels a vertical mile into the Grand Canyon in search of them.
The Lake Erie water snake, once on the brink of extinction, now looks to be rebounding--thanks mainly to the invasive goby fish that's wreaking havoc on the Great Lakes ecosystem. Can scientists studying this environmental anomaly find a healthy ecological balance?
Metamorphosis seems like the ultimate evolutionary magic trick - the amazing transformation of one creature into a totally different being: one life, two bodies. From Ovid to Kafka to X-Men, tales of metamorphosis richly permeate human culture. The myth of transformation is so common that it seems almost pre-programmed into our imagination. But is the scientific fact of metamorphosis just as strange as fiction or... even stranger? Filmmaker David Malone explores the science behind metamorphosis. How does it happen and why? And might it even, in some way, happen to us?
2013 • Nature