The human eye is an amazing mechanism, able to detect anywhere from a few photons to a few quadrillion, or switch focus from the screen in front of you to the distant horizon in a third of a second. How did these complex structures evolve? Joshua Harvey details the 500 million year story of the human eye.
Ascends a kapok in the South American tropical rainforest to observe "the greatest proliferation of life that you can find anywhere on the surface of the Earth. There are two main causes for this: warmth and wetness. As this climate is constant, there are no seasons, so trees vary greatly in their flowering cycles.
Life in the sea rebounded with a vengeance in the Devonian. Dozens of monstrous predators emerged, like the 40-foot long Dunkleosteus. Nearly everything was wiped out in Earth’s second mass extinction. But the stage was set for an explosion of life on land.
Reptiles and amphibians look like hang-overs from the past. But they overcome their shortcomings through amazing innovation. The pebble toad turns into a rubber ball to roll and bounce from its enemies. Extreme slow-motion shows how a Jesus Christ lizard runs on water, and how a chameleon fires an extendible tongue at its prey with unfailing accuracy. The camera dives with a Niuean sea snake, which must breed on land but avoids predators by swimming to an air bubble at the end of an underwater tunnel. In a TV first, Komodo dragons hunt a huge water-buffalo, biting it to inject venom, then waiting for weeks until it dies. Ten dragons strip the carcass to the bone in four hours.