This first episode of this evening's unsurpassed and inspiring documentary deals with savanna, steppe, tundra, and prairie, and looks at the importance and resilience of grasses in such treeless ecosystems.  Their vast expanses contain the largest concentration of animal life.  In Outer Mongolia, a herd of Mongolian gazelle flee a bush fire and has to move on to new grazing, but grass can repair itself rapidly and soon reappears.  On the Arctic tundra during spring, millions of migratory snow geese arrive to breed and their young are preyed on by Arctic foxes.  Meanwhile, time-lapse photography depicts moving herds of caribou as a calf is brought down by a chasing wolf.  On the North American prairie, bison engage in the ritual to establish the dominant males.  The Tibetan Plateau is the highest of the plains and despite its relative lack of grass, animals do survive there, including yak and wild ass.  However, the area's most numerous resident is the pika, whose nemesis is the Tibetan fox.  In tropical India, the tall grasses hide some of the largest creatures and also the smallest, such as the pygmy hog.  The final sequence depicts the African savannah and elephants that are forced to share a waterhole with a pride of thirty lions.  The insufficient water makes it an uneasy alliance and the latter gain the upper hand during the night when their hunger drives them to hunt and eventually kill one of the pachyderms.

This second episode examines jungles and tropical rainforests.  These environments occupy only 3% of the land yet are home to over half of the world's species.  New Guinea is inhabited by almost 40 kinds of birds of paradise, which avoid conflict with each other by living in different parts of the island.  Some of their elaborate courtship displays are shown.  Within the dense forest canopy, sunlight is prized, and the death of a tree triggers a race by saplings to fill the vacant space.  Figs are a widespread and popular food, and as many as 44 types of bird and monkey have been observed picking from a single tree.  The sounds of the jungle throughout the day are explored, from the early morning calls of siamangs and orangutans to the nocturnal cacophony of courting tree frogs.  The importance of fungi to the rainforest is illustrated by a sequence of them fruiting, including a parasite called cordyceps.  The mutual benefits of the relationship between carnivorous pitcher plants and red crab spiders is also discussed.  In the Congo, roaming forest elephants are shown reaching a clearing to feed on essential clay minerals within the mud.  Finally, chimpanzees are one of the few jungle animals able to traverse both the forest floor and the canopy in search of food.  In Uganda, members of a 150-strong community of the primates mount a raid into neighboring territory in order to gain control of it.

This first episode of this evening's inspiring documentary describes the course taken by rivers and some of the species that take advantage of such a habitat.  Only 3% of the world's water is fresh, yet all life is ultimately dependent on it.  Its journey begins as a stream in the mountains, illustrated by Venezuela's Tepui, where there is a tropical downpour almost every day.  It then travels hundreds of miles before forming rapids.  With the aid of some expansive helicopter photography, one sequence demonstrates the vastness of Angel Falls, the world's highest free-flowing waterfall.  Its waters drop unbroken for nearly 1,000 meters and are blown away as a mist before they reach the bottom.  The erosive nature of rivers is shown by the Grand Canyon, created over five million years by the Colorado River.  In Japan, the water is inhabited by the biggest amphibian, the two-meter long giant salamander, while in the northern hemisphere, salmon undertake the largest freshwater migration, and are hunted en route by grizzly bears.  Also featured are smooth coated otters repelling mugger crocodiles and the latter's Nile cousin ambushing wildebeest as they cross the Mara River.  Roseate spoonbills are numerous in the Pantanal and are prey to spectacled caiman.  In addition, there are cichlids, piranhas, river dolphins and swimming crab-eating macaques.

This second episode surveys the coniferous and deciduous seasonal woodland habitats ─ the most extensive forests on Earth.  Conifers begin sparsely in the Arctic but soon dominate the land, and the taiga circles the globe, containing a third of all the Earth's trees.  Few creatures can survive the Arctic climate all year round, but the moose and wolverine are exceptions.  1600 kilometers to the south, on the Pacific coast of North America, conifers have reached their full potential.  These include some of the world's tallest trees:  the redwoods.  Here, a pine marten is shown stalking a squirrel, and great grey owl chicks take their first flight.  Further south still, in the Valdivian forests of Chile, a population of smaller animals exist, including the pudú and the kodkod.  During spring in a European broad-leaved forest, a mandarin duck leads its day-old family to leap from its tree trunk nest to the leaf litter below.  On a summer night on North America's east coast, periodical cicadas emerge en masse to mate ─ an event that occurs every seventeen years.  After revisiting Russia's Amur leopards in winter, a timelapse sequence illustrates the effect of the ensuing spring on the deciduous forest floor.  In India's teak forests, a langur monkey strays too far from the chital that act as its sentinels and falls prey to a tiger.