Learn more about Audible at https://Audible.com/Eons or text “Eons” to 500-500 PBS Member Stations rely on viewers like you. To support your local station, go to http://to.pbs.org/DonateEons The first era of our current eon, the Paleozoic Era, is probably the most deceptively fascinating time in Earth’s history. With near-constant revolutions in life, punctuated by catastrophic extinctions, it is also one of the most chaotic. Correction! At 9:19, we erroneously refer to Dimetrodon as an herbivore. It was definitely a carnivore. We even made a whole video about Dimetrodon and their carnivorous ways in a previous episode: https://www.youtube.com/watch?v=SR3OOP9mImI Thanks to everyone who pointed out our error! Thanks to Studio 252mya for their illustrations. You can find more of their work here: https://252mya.com/licensing Produced for PBS Digital Studios. Want to follow Eons elsewhere on the internet? Facebook - https://www.facebook.com/eonsshow Twitter - https://twitter.com/eonsshow Instagram - https://www.instagram.com/eonsshow/ References: https://www.nature.com/news/what-sparked-the-cambrian-explosion-1.19379 http://science.sciencemag.org/content/341/6152/1355.full https://academic.oup.com/icb/article/43/1/157/604502 https://zoologicalletters.biomedcentral.com/articles/10.1186/s40851-014-0004-x http://burgess-shale.rom.on.ca/en/science/burgess-shale/03-fossils.php#composition http://austhrutime.com/cambrian_period.htm http://dev.biologists.org/content/132/11/2503 https://park.org/Canada/Museum/extinction/camcause.html https://ac-els-cdn-com.libproxy.mtroyal.ca/S0031018210003184/1-s2.0-S0031018210003184-main.pdf?_tid=a7fd64d8-f408-11e7-96fe-00000aab0f27&acdnat=1515370547_3b81bba2e15582b09e40465c75c9c419 http://www.nature.com.libproxy.mtroyal.ca/articles/s41561-017-0006-3 http://onlinelibrary.wiley.com/doi/10.1111/j.1502-3931.2008.00118.x/abstract;jsessionid=D36B0CF621E81915838CB1BF7A3CB985.f04t02 http://onlinelibrary.wiley.com/doi/10.1111/j.1502-3931.2008.00115.x/abstract https://www.fossilhunters.xyz/disappeared-species/the-major-extinctions-and-their-causes-cambrianordovician.html http://www.sciencedirect.com/science/article/pii/S1342937X13000154?via%3Dihub http://www.sciencedirect.com/science/article/pii/S1002007107000196 https://web.archive.org/web/19991009125017/http://www.clas.ufl.edu/users/pciesiel/gly3150/plant.html https://www.newscientist.com/article/dn21417-first-land-plants-plunged-earth-into-ice-age/ https://link.springer.com/article/10.1134/S0001437014050014 http://www.sciencedirect.com/science/article/pii/S1342937X13000154 https://www.researchgate.net/publication/46817981_Silurian-Devonian_boundary_events_and_their_influence_on_cephalopod_evolution_evolutionary_significance_of_cephalopod_egg_size_during_mass_extinctions https://pubs.usgs.gov/pp/1066p/report.pdf http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0179262 http://blogs.discovermagazine.com/d-brief/2013/09/25/first-jawed-fish-had-one-ugly-face/#.Wg9iLhNSyfR http://sciencythoughts.blogspot.ca/2013/12/a-scorpion-from-late-devonian-of-south.html https://www.newscientist.com/article/dn18346-oldest-footprints-of-a-four-legged-vertebrate-discovered/ http://onlinelibrary.wiley.com/doi/10.1111/j.1420-9101.2008.01512.x/full https://www.nature.com/articles/nature10969?message-global=remove https://ac.els-cdn.com/S0960982215009276/1-s2.0-S0960982215009276-main.pdf?_tid=7f5f51ce-0486-11e8-9da1-00000aab0f6c&acdnat=1517183815_9a41800ae5d0f975bf3b4dfb1f81fdac https://books.google.com/books?id=hFLmCAAAQBAJ&pg=PA2&lpg=PA2&dq=first+terrestrial+arachnids&source=bl&ots=tyPhAKSwrP&sig=xK1ZdvR6toJsYAhfIUHUQmlWFks&hl=en&sa=X&ved=0ahUKEwixx-747fvYAhUE2WMKHZQOC8MQ6AEIiwEwEQ#v=onepage&q=first%20terrestrial%20arachnids&f=false