Biology's Big Bang: The Cambrian Explosion

538 million years ago, life on Earth changed forever. In an evolutionary burst known as the Cambrian Explosion, complex animals rapidly appeared in the oceans, laying the foundations for almost every major animal group alive today. Tristan Hughes is joined by the mighty Henry Gee to explore biology’s 'Big Bang'. What triggered this extraordinary leap in evolutionary complexity? Why did creatures with eyes, shells and limbs emerge so suddenly in the fossil record? And what can the Cambrian Explosion reveal about the origins of animal life and the history of our planet? 0:00 Introduction 0:53 Introducing Henry Gee: Palaeontologist and evolutionary biologist 2:12 Darwin's dilemma: The mysterious gap in the Victorian fossil record 3:51 Skeletons and armour: What can actually become a fossil 4:22 Dating the detonation: Pinpointing the start of the Cambrian period 6:21 The Ancients live tour announcement 7:31 Setting the scale: How much further back is the Cambrian than dinosaurs 8:22 Before the bang: The Great Oxidation Event and multicellular life 10:05 Rodinia breaking up: Supercontinents and snowball Earth episodes 11:20 Squishy sea creatures: The mysterious Ediacaran fauna 12:47 Finding 600-million-year-old fossils in a public park in Leicester 14:00 The Garden of Ediacara: An ecology without predators or prey 16:17 Sponges and minerals: Oxygenating the oceans with calcium 18:07 Mountains crumbling to the sea: The ultimate geological storm 19:42 Direction of travel: The groundbreaking evolution of the anus 21:47 The eyes have it: Andrew Parker's light switch theory 22:26 Cloudina and trilobites: The earliest records of teeth and predation 23:56 Iconic adaptable woodlice: The marvellous diversity of the trilobite 28:05 Hallucigenia and velvet worms: The dreamlike armoured creatures 29:12 Opabinia: The Teletubbies Noo-Noo of the prehistoric world 30:00 Anomalocaris: The terrifying T-Rex of the Cambrian seas 31:56 The arthropod head problem: Reconstructing fossilised nervous systems 36:12 Joining the backbone club: What defines a vertebrate 38:11 Pikaia, Haikouichthys and the evolution of the earliest four-eyed fish 40:08 From lenses to bio-rhythms: How extra eyes became the pineal gland 42:03 Sucking seawater: Why sea squirts are our closest living relatives 47:21 Upgrading defences: Jawless armoured fish and nightmarish sea scorpions 51:09 Extending the detonation: How long did the Cambrian explosion last 54:53 Vanishing from the record: The hidden history of ancient parasites 58:10 The modern kaleidoscope: How biodiversity has flourished since the first flowering Presented by Tristan Hughes. Producers are Joseph Knight & McKenna Fernandez, senior producer is Anne-Marie Luff. Editor is Matthew Wilson. Channel manager is Vilde Øksnes. Sign up to History Hit for hundreds of hours of original documentaries, with a new release every week and ad-free podcasts. Sign up at https://www.historyhit.com/subscribe. All music from Epidemic Sounds. #HistoryHitPodcast #TheAncients #Evolution