In Lesson 1, we explore the anatomy and adaptations of birds, and meet the Victorian scientists who first suspected the link between the terrible lizards and modern birds. In order to fly, birds have undergone a series of anatomical specializations that distinguishes them from other vertebrates. However, many of the most striking and anatomically unusual traits of birds originated over 230 million years ago with the very first theropod dinosaurs. Just a quick note before you get started: 'Palaios' is the Greek word for 'ancient', so palaeontology or paleontology is the study of ancient life. Both spellings are correct, with palaeontology used in Britain, and paleontology more common in the US.