Episode 1 Water Dwellers – Begins with an illustration of the giant impact hypothesis approximately 4.4 billion years ago when the Earth was formed, it is conjectured that a planet like object referred to as Theia collided into the early Earth, dynamically reshaping the Earth and forming the moon. The episode then jumps ahead to the Cambrian Explosion, showing the first diversification of life in the sea. Strange predators called Anomalocaris feed on trilobites, and fight with each other, whereupon the wounded loser is attacked by a school of Haikouichthys, described as the first vertebrate. The segment moves on to the Silurian period and the jawless fish Cephalaspis and the marine scorpion Brontoscorpio and the giant eurypterid Pterygotus. Other species in this episode are Hynerpeton, Stethacanthus and Hyneria.
Episode 2 Reptile’s Beginnings – Starts in the swampy coal forests of the Carboniferous. It explains that because of a much higher oxygen content in the atmosphere, giant land arthropods evolved, such as a Mesothelae, Meganeura and Arthropleura. Other species include Petrolacosaurus, Reptiliomorphs, Proterogyrinus. A storm brews and the narrator explains that its high oxygen content makes the atmosphere very combustible, so lightning is a real danger. The episode then moves on to the early Permian, where trees of the Carboniferous have been replaced with more advanced conifers that are better adapted to survive in a changing climate. Petrolacosaurus has evolved into Edaphosaurus, a pelycosaur (this is impossible, as Petrolacosaurus was a diapsid reptile, related to modern lizards, snakes, crocodiles, and birds, whereas Edaphosaurus was a synapsid, related to modern mammals). At the end the narrator says that the reptiles evolve to tighten their grip on land, becoming “new reptiles.”
Episode 3 Clash of Titans – Set in the Late Permianon the supercontinent Pangaea, which was covered by a vast and inhospitable desert. In this arid climate, early therapsids, which are described as more “mammal like” than reptile are shown fighting to survive alongside other animals. The narrator explains that mammals are destined to be confined to the shadows as a new group of animals becomes the dominant species on Earth. The age of mammal like reptiles is over. This is the beginning of the Age of Dinosaurs.