A look at one of the most famous habitats on the planet, the Serengeti in East Africa, a vast grassland that is home to some of the greatest concentrations of herbivores on the continent. But what is the key to this exceptional grassland that allows such density and diversity?
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.
In the thick of the jungle of Rwanda's Volcanoes National Park, an infant mountain gorilla has been caught in a snare. If the rope is not removed quickly enough, the young gorilla could lose its hand. In order to remove the snare, a team of veterinarians will first need to sedate the infant's mother. But if the infant screams too much, the three 400-pound adult males that form part of this gorilla group will all attack. Everything must go perfectly, or there's no telling what could happen. And being jungle medicine, things rarely go perfectly. The pioneering group of vets performing this medical intervention is known as Gorilla Doctors. Led by Canadian Mike Cranfield, they work in Rwanda, the Democratic Republic of Congo and Uganda, where the world's last Mountain Gorillas can be found.
After the Permian period, the epic saga of evolution and extinction on Earth produced the world's first dinosaurs, plesiosaurs and pterosaurs. They dominated land, sea and air until another period of extreme volcanism generated vast waves of lava and toxic gas and killed roughly 75% of all species.
David Attenborough journeys to both Polar Regions to investigate what rising temperatures will mean for the people and wildlife that live there and for the rest of the planet. David starts out at the North Pole, standing on sea ice several metres thick, but which scientists predict could be Open Ocean within the next few decades. The Arctic has been warming at twice the global average, so David heads out with a Norwegian team to see what this means for polar bears. He comes face-to-face with a tranquilised female, and discovers that mothers and cubs are going hungry as the sea ice on which they hunt disappears. In Canada, Inuit hunters have seen with their own eyes what scientists have seen from space; the Arctic Ocean has lost 30% of its summer ice cover over the last 30 years. For some, the melting sea ice will allow access to trillions of dollars worth of oil, gas and minerals. For the rest of us, it means the planet will get warmer, as sea ice is important to reflect back the sun's energy. Next David travels to see what's happening to the ice on land: in Greenland, we follow intrepid ice scientists as they study giant waterfalls of meltwater, which are accelerating iceberg calving events, and ultimately leading to a rise in global sea level. Temperatures have also risen in the Antarctic - David returns to glaciers photographed by the Shackleton expedition and reveals a dramatic retreat over the past century. It's not just the ice that is changing - ice-loving adelie penguins are disappearing, and more temperate gentoo penguins are moving in. Finally, we see the first ever images of the largest recent natural event on our planet - the break up of the Wilkins Ice Shelf, an ice sheet the size of Jamaica, which shattered into hundreds of icebergs in 2009.