Chris Packham aims to raise enough money to plant 100,000 trees across Britain, by asking viewers to contribute to The Woodland Trust. Martin Hughes-Games, JB Gill and Clare Nasir also take a closer look at the science of trees, exploring how they can lower carbon emissions, fight flooding and reduce pollution.
Otters are playful, adaptable and champion swimmers - they've captivated cameraman Charlie Hamilton James for the last 25 years. He's filmed them more than anyone else and now, through the eyes of three orphaned river otters, a set of groundbreaking experiments and some incredible wild encounters, Charlie wants to reveal their survival secrets and exactly why he believes they're so special.
Formed from the remains of a 2.5 million-year-old imploded volcano, the Ngorongoro crater is a study in contradictions: On one hand, it's a self-sustained and plentiful land that provides for the many animals that call it home. Conversely, its isolation threatens the existence of many of its key species. What does the future hold for this unique habitat?
The final episode explores dinosaurs' extraordinary ability to survive. Featured dinosaurs include the bizarre magyarosaurus, which lived in the shadow of the biggest flying animal - hatzegopteryx - and showed an amazing adaptation to island life; and the weird nothronychus, a carnivore that gave up meat eating. This astonishing capacity to evolve into ever more diverse and bizarre forms meant that dinosaurs not only spread throughout the world, but also dominated life upon it for more than 160 million years. It was only an unprecedented extraterrestrial event that finally saw the end of planet dinosaur.