Most vertebrate animals on land get around on all fours, but some of us have committed to two-legged locomotion. This episode, we explore the various ways animals have evolved bipedalism and the many benefits that come with it. We’ll also take a look at how we identify bipedal animals in the fossil record, and we’ll zoom in on the evolutionary story behind Earth history’s most successful bipeds. In the news: potato origins, trilobite legs, bone worm burrows, and australopithecine sexes. Time markers:Intro & Announcements: 00:00:00 News: 00:07:35 Main discussion, Part 1: 00:35:15Main discussion, Part 2: 01:10:50Patron question: 02:05:55 Check out our website for this episode’s blog post and more: http://commondescentpodcast.com/ Join us on Patreon to support the podcast and enjoy bonus content: https://www.patreon.com/commondescentpodcast Subscribe to Curiosity Box using our Affiliate Link: https://www.curiositybox.com/CommonDescent And get 25% off the first box with code descent25 Got a topic you want to hear about? Submit your episode request here: https://commondescentpodcast.com/request-a-topic/ Lots more ways to connect with us: https://linktr.ee/common_descent The Intro and Outro music is “On the Origin of Species” by Protodome. More music like this at http://ocremix.org Musical Interludes are "Professor Umlaut" by Kevin MacLeod (incompetech.com). Licensed under Creative Commons: By Attribution 3.0 http://creativecommons.org/licenses/by/3.0

Mutation. It is the key to our evolution. As our cells constantly divide and reproduce and replicate our DNA, errors and inconsistencies develop, leading to the incredible variation of life that drives evolutionary change. This episode, we explore the genetic mechanisms behind mutation and we discuss how scientists study mutations to understand the evolutionary history of life on Earth. In the news: Neanderthal tools, caiman food, dancing dinosaurs, and ancient integument. Time markers:Intro & Announcements: 00:00:00 News: 00:09:25 Main discussion, Part 1: 00:40:50 Main discussion, Part 2: 01:35:00 Patron question: 02:28:55 Check out our website for this episode’s blog post and more: http://commondescentpodcast.com/ Join us on Patreon to support the podcast and enjoy bonus content: https://www.patreon.com/commondescentpodcast Got a topic you want to hear about? Submit your episode request here: https://commondescentpodcast.com/request-a-topic/ Lots more ways to connect with us: https://linktr.ee/common_descent The Intro and Outro music is “On the Origin of Species” by Protodome. More music like this at http://ocremix.org Musical Interludes are "Professor Umlaut" by Kevin MacLeod (incompetech.com). Licensed under Creative Commons: By Attribution 3.0 http://creativecommons.org/licenses/by/3.0

On the outside, shrews might seem like standard tiny mammals, but their anatomy and lifestyle are highly specialized. This episode, with help from special guest Derek den Ouden, we explore the diverse habits of shrews, the anatomical features that set them apart, and how they thrive worldwide despite being perpetually on the brink of starvation. Then, we consider the extinct diversity of shrews in the fossil record. In the news: stubborn bass, choking fish, tomato defenses, and some really old rocks. Time markers:Intro & Announcements: 00:00:00News: 00:09:35Main discussion, Part 1: 00:45:25Main discussion, Part 2: 01:40:50Patron question: 02:12:35 Find Derek online at @DenoudenDerek Check out our website for this episode’s blog post and more: http://commondescentpodcast.com/ Join us on Patreon to support the podcast and enjoy bonus content: https://www.patreon.com/commondescentpodcast Check out our friends’ new data management app, Cnidarity: https://cnidarity.com/ Got a topic you want to hear about? Submit your episode request here: https://commondescentpodcast.com/request-a-topic/ Lots more ways to connect with us: https://linktr.ee/common_descent The Intro and Outro music is “On the Origin of Species” by Protodome. More music like this at http://ocremix.org Musical Interludes are "Professor Umlaut" by Kevin MacLeod (incompetech.com). Licensed under Creative Commons: By Attribution 3.0 http://creativecommons.org/licenses/by/3.0

Lizards are extremely good at becoming snake-shaped. A long body with small or absent limbs is a shape that has evolved dozens of times across nearly every major lineage of lizards. This episode, we explore the diversity of leglessness in lizards, we discuss which groups have done it and which groups have done it best, and we examine what’s known about the repeated evolution of this unexpected body shape. In the news: giant dusky salamander, very early footprints, a Denisovan skull, a mammoth tusk boomerang, and night lizards. Time markers:Intro & Announcements: 00:00:00News: 00:06:25Main discussion, Part 1: 00:41:50Main discussion, Part 2: 01:33:55Patron question: 02:16:35 Check out our website for this episode’s blog post and more: http://commondescentpodcast.com/ Join us on Patreon to support the podcast and enjoy bonus content: https://www.patreon.com/commondescentpodcast Happy Disability Pride Month!AmeriDisability https://www.ameridisability.com/National Disability Rights Network https://www.ndrn.org/ Got a topic you want to hear about? Submit your episode request here: https://commondescentpodcast.com/request-a-topic/ Lots more ways to connect with us: https://linktr.ee/common_descent The Intro and Outro music is “On the Origin of Species” by Protodome. More music like this at http://ocremix.org Musical Interludes are "Professor Umlaut" by Kevin MacLeod (incompetech.com). Licensed under Creative Commons: By Attribution 3.0 http://creativecommons.org/licenses/by/3.0

Today’s crocs are iconic semi-aquatic predators, but their extended family tree features lots of land-dwelling cousins. This episode, we take a tour through croc evolutionary history and explore the many times these reptiles have taken to life on dry land. We’ll examine what features these terrestrial crocs shared, which ones they didn’t, and what their fossils tell us about how the shape of crocs has changed over time. In the news: sauropod guts, Australian biomarkers, butterfly scales, and tropical archosaurs. Time markers:Intro & Announcements: 00:00:00News: 00:07:25Main discussion, Part 1: 00:44:20Main discussion, Part 2: 01:23:20Patron question: 02:17:25 Check out our website for this episode’s blog post and more: http://commondescentpodcast.com/ Join us on Patreon to support the podcast and enjoy bonus content: https://www.patreon.com/commondescentpodcast Got a topic you want to hear about? Submit your episode request here: https://commondescentpodcast.com/request-a-topic/ Lots more ways to connect with us: https://linktr.ee/common_descent The Intro and Outro music is “On the Origin of Species” by Protodome. More music like this at http://ocremix.org Musical Interludes are "Professor Umlaut" by Kevin MacLeod (incompetech.com). Licensed under Creative Commons: By Attribution 3.0 http://creativecommons.org/licenses/by/3.0

For over 100 million years, North America and Asia have been connected over the Pacific Ocean through a region called Beringia. The comings and going of plants and animals across this connection have shaped ecosystems of the past and present. This episode, we explore the geologic history of the region and which ancient species have managed to live in and move through Beringia. In the news: early sperm whales, BC plesiosaurs, megatooth shark food, and Arctic nesting birds. Time markers:Intro & Announcements: 00:00:00News: 00:09:10Main discussion, Part 1: 00:35:25Main discussion, Part 2: 01:02:15Patron question: 01:40:40 Check out our website for this episode’s blog post and more: http://commondescentpodcast.com/ Join us on Patreon to support the podcast and enjoy bonus content: https://www.patreon.com/commondescentpodcast Some LGBTQIA+ organizations in the southeast US:Trans Aid Nashville: https://www.transaidnashville.org/ Out Memphis: https://www.outmemphis.org/ Southerners on New Ground: https://southernersonnewground.orgShoutout to Vic Michaelis for these links: www.instagram.com/vicmmic/ Got a topic you want to hear about? Submit your episode request here: https://commondescentpodcast.com/request-a-topic/ Lots more ways to connect with us: https://linktr.ee/common_descent The Intro and Outro music is “On the Origin of Species” by Protodome. More music like this at http://ocremix.org Musical Interludes are "Professor Umlaut" by Kevin MacLeod (incompetech.com). Licensed under Creative Commons: By Attribution 3.0 http://creativecommons.org/licenses/by/3.0

Take a deep breath and appreciate for a moment the organs that let you do it so efficiently. Lungs are an invaluable tool for life out of the water, and are therefore a favorite topic for paleontologists interested in early animals on land. This episode, we explore the diversity of modern lungs and the few but fascinating insights we have into the lungs of ancient animals, from dinosaurs to the first terrestrial vertebrates. In the news: trilobite sizes, polar forests, early footprints, and cicadas. Time markers:Intro & Announcements: 00:00:00News: 00:05:50Main discussion, Part 1: 00:31:30Main discussion, Part 2: 01:21:35Patron question: 02:05:35 Check out our website for this episode’s blog post and more: http://commondescentpodcast.com/ Listen to our new podcast, Leaf it to Us!https://linktr.ee/leafittouspod Join us on Patreon to support the podcast and enjoy bonus content: https://www.patreon.com/commondescentpodcast Got a topic you want to hear about? Submit your episode request here: https://commondescentpodcast.com/request-a-topic/ Lots more ways to connect with us: https://linktr.ee/common_descent The Intro and Outro music is “On the Origin of Species” by Protodome. More music like this at http://ocremix.org Musical Interludes are "Professor Umlaut" by Kevin MacLeod (incompetech.com). Licensed under Creative Commons: By Attribution 3.0 http://creativecommons.org/licenses/by/3.0

Bears are among the most charismatic and impressive mammals. They have large bodies, very flexible lifestyles, and an extensive fossil record that includes some of the best-preserved and largest fossil mammals of all time. This episode, we explore what makes bears so distinctive and successful, and how their diversity has changed over time. In the news: ancient alligators, rattlesnake venom, late land crocs, pterosaur tracks, and Caribbean crocodiles. Time markers:Intro & Announcements: 00:00:00News: 00:05:45Main discussion, Part 1: 00:43:25Main discussion, Part 2: 01:28:25Patron question: 02:12:25 Check out our website for this episode’s blog post and more: http://commondescentpodcast.com/ Listen to our new podcast, Leaf it to Us!https://linktr.ee/leafittouspod Join us on Patreon to support the podcast and enjoy bonus content: https://www.patreon.com/commondescentpodcast Got a topic you want to hear about? Submit your episode request here: https://commondescentpodcast.com/request-a-topic/ Lots more ways to connect with us: https://linktr.ee/common_descent The Intro and Outro music is “On the Origin of Species” by Protodome. More music like this at http://ocremix.org Musical Interludes are "Professor Umlaut" by Kevin MacLeod (incompetech.com). Licensed under Creative Commons: By Attribution 3.0 http://creativecommons.org/licenses/by/3.0

Just about every body of water on Earth, from oceans to puddles, is home to an ecosystem of tiny drifting organisms. This episode, we discuss what sorts of organisms we might expect to find in a swarm of plankton, we’ll explore how plankton is so fundamental to biological and geological systems on Earth, and we’ll take some time to lay out some of the many ways that ancient plankton are a crucial part of the fossil record. In the news: climbing reptiles, croc extinctions, Ashfall rhinos, and ankylosaur tracks. Time markers:Intro & Announcements: 00:00:00News: 00:05:40 Main discussion, Part 1: 00:35:15 Main discussion, Part 2: 01:23:00 Patron question: 02:00:30 Check out our website for this episode’s blog post and more: http://commondescentpodcast.com/ Join us on Patreon to support the podcast and enjoy bonus content: https://www.patreon.com/commondescentpodcast Listen to Will talk speculative evolution on the Nerd Trek Podcasthttps://open.spotify.com/episode/2NzdG8TMfwGLzpP8sKXHQA And listen to David talk de-extinction on the House of Podhttps://open.spotify.com/show/3z6EgP0BzaHQoXzCtxQ32t Support links:ACLU: https://www.aclu.org/ Got a topic you want to hear about? Submit your episode request here: https://commondescentpodcast.com/request-a-topic/ Lots more ways to connect with us: https://linktr.ee/common_descent The Intro and Outro music is “On the Origin of Species” by Protodome. More music like this at http://ocremix.org Musical Interludes are "Professor Umlaut" by Kevin MacLeod (incompetech.com). Licensed under Creative Commons: By Attribution 3.0 http://creativecommons.org/licenses/by/3.0

Silver Screen Science is our series where we explore how science is portrayed on the big screen. This year, we’re focused on one recurring franchise: Planet of the Apes! Finally, we visit the ongoing prequel franchise with the story of how it all got started: Rise of the Planet of the Apes. Check out our website for blog posts and more: http://commondescentpodcast.com/ Join us on Patreon to support the podcast and enjoy bonus content: https://www.patreon.com/commondescentpodcast Lots more ways to connect with us: https://linktr.ee/common_descent The Intro and Outro music is “On the Origin of Species” by Protodome. More music like this at http://ocremix.org.