A visit to the Amazon jungle - the world's largest rainforest and home to the widest variety of plants and animals on Earth. he diversity of life in the jungle is so great that in just two square miles scientists have counted 3,000 varieties of ants, 530 types of birds and 11 species of monkey. But despite the huge range of life that flourishes here, survival is never easy.

In Africa's ancient south west corner, two extraordinary deserts sit side by side. Water is in short supply, yet these deserts are somehow full of life because the creatures that live here have turned the rules of survival on their head. This film celebrates nature's ingenuity, no matter how tough it gets. In the Kalahari scrublands, clever meerkats are outsmarted by a wily bird, solitary and belligerent black rhinos get together to party and giant insects stalk huge flocks of birds. Rain almost never falls in the Namib - instead it must make do with vaporous, vanishing fog. The creatures in this, the world's oldest desert, have gone to the extremes, as spiders wheel to escape and a desert giraffe fights to defend his scant resources in the greatest giraffe battle ever filmed.

A Winning Design clarifies what makes a mammal different from reptiles and birds. No, it isn't egg-laying: both the platypus and the echidna are egg-laying mammals; it's their ability to adapt. And it's this adaptability that becomes the crux of the remainder of the series. From the tiniest bat to the massive blue whale, all mammals share the ability to nurture their young on milk and regulate their own temperatures.

Spring arrives in the polar regions, and the sun appears after an absence of five months; warmth and life return to these magical ice worlds - the greatest seasonal transformation on our planet is underway. Male Adelie penguins arrive in Antarctica to build their nests - it takes a good property to attract the best mates and the males will stop at nothing to better their rivals! But these early birds face the fiercest storms on the planet. In the Arctic, a polar bear mother is hunting with her cubs. Inland, the frozen rivers start to break up and billions of tons of ice are swept downstream in the greatest of polar spectacles. This melt-water fertilizes the Arctic Ocean, feeding vast shoals of Arctic cod and narwhal. The influx of freshwater accelerates the breakup of the sea-ice - an area of ice the size of Australia will soon vanish from the Arctic. On land, a woolly bear caterpillar emerges from the snow having spent the winter frozen solid. Caterpillars normally become moths within months of hatching, but life is so harsh here that the woolly bear takes 14 years to reach adulthood. Once mature it has only days to find a mate before it dies! Alongside the caterpillars white Arctic wolves race to raise their adorable cubs before the cold returns.

Grasslands feed the world. Over thousands of years, we humans have learned to grow grains on the grasslands and domesticate the creatures that live there. Our success has propelled our population to almost seven billion people. But this episode reveals that, even today, life in the 'Garden of Eden' isn't always rosy. We walk with the Dorobo people of Kenya as they bravely attempt to scare off a pride of hungry lions from their freshly caught kill. We gallop across the Steppe with extraordinary Mongolian horsemen who were 'born in the saddle'. And in a perfect partnership with nature built up over generations Maasai children must literally talk to the birds! The honeyguide leads them to find sweet treats, but they'll have to repay the favour.

The very heart of Africa is covered in dense tropical rainforest. The animals that live here find the most ingenious ways to carve out their space in a claustrophobic landscape. Danger lurks in every shadow, but some animals thrive here, from honey-stealing chimps to birds with a lineage as old as the dinosaurs, thundering elephants and kick-boxing frogs. Here in the Congo, no matter how tough the competition, you must stand up and fight for yourself and your patch.