This programme looks at the evolution of fish. They have developed a multitude of shapes, sizes and methods of propulsion and navigation. The sea squirt, the lancelet and the lamprey are given as examples of the earliest, simplest types. Then, about 400 million years ago, the first back-boned fish appeared. The Kimberley Ranges of Western Australia are, in fact, the remnants of a coral reef and the ancient seabed. There, Attenborough discovers fossils of the earliest fish to have developed jaws. These evolved into two shapes of creature with cartilaginous skeletons: wide ones (like rays and skates) and long ones (like sharks).
Gorillas, rhinos, and elephants, three of nature's largest animals, deliver enormous babies. But the immense size of these newborns stands in stark contrast to their vulnerability. Everything from feeding to protection against predators to learning essential life skills falls on one devoted parent: their mothers.
The Belize Barrier Reef is the second-largest coral reef system in the world. Estimated to be nearly 4,000 years old, its waters are home to an immense marine ecosystem. Explore a deep blue wilderness brimming with rare, exotic fish, sea turtles, sharks, and huge green morays.