Meet the big birds, a feathered family who have never flown a day in their lives! From ostriches to kiwis, these bizarre birds appear to be nature's greatest novelty act. How they came to be and how they continue to survive is a fascinating tale that has long captivated Sir David Attenborough. It is a story of dedicated dads, enormous eggs and a serious need for speed. And far from being the court jesters of the animal world, these flightless curiosities once nearly ruled the land.
The next programme explores the various sea-living invertebrates. In Morocco, the limestones are 600 million years old, and contain many invertebrate fossils. They fall broadly into three categories: shells, crinoids and segmented shells. The evolution of shelled creatures is demonstrated with the flatworm, which eventually changed its body shape when burrowing became a necessity for either food or safety. It then evolved shielded tentacles and the casings eventually enveloped the entire body: these creatures are the brachiopods. The most successful shelled animals are the molluscs, of which there are some 80,000 different species.