Going down into these narrow flooded passageways is not for the faint-hearted but, with only an estimated one percent of the caves explored, it is an opportunity for the team to write themselves into cave diving history, by pushing further in than anyone has before. This is a challenge that tests even the most accomplished cave divers. Steve must face the terrors of being lost in an underwater silt cloud in a cave. But there is a bigger issue at stake. All life in the Yucatan depends on the fresh water in this network of caves, but it's being contaminated by human development. With every metre the team maps, it adds to the knowledge of the system, which, in turns, helps protect it for future generations.
In the northeast corner of Botswana, the rainy season is months away. The sausage tree offers a beguiling oasis for wildlife--from birds and insects, to much larger mammals like elephants--all reeling from the dry conditions. Then, as the rains descend, brilliant red flowers bloom and entice parrots, squirrels, and sunbirds to help with pollination. Summer allows the sausage tree to live up to its name, delivering massive, sausage-shaped fruit, a nutritious feast and a cornerstone of life in this exotic ecosystem.
The first programme shows how sharks are the ocean's great predators, living in every ocean and hunting in every way. Blacktip sharks hunt in huge packs and herd fish into baitballs, tasselled wobbegongs are ambush hunters, Greenland sharks live under the arctic ice, and whitetip reef sharks are the masters of hunting at night. The finale shows the great white in its hunt for fur seals off the coast of South Africa.
The theory of evolution explains how the enormous variety of life could come into existence. How it is possible for primitive life forms to spawn the millions of different creatures, that exist today. Unfortunately, evolution is often misunderstood, because it's mechanisms seem counter intuitive. By using visualizations, infographics and appealing characters, the viewer is more likely to understand it the complex information.