It's an easy mistake to think of the Moon as a simple accessory to our planet, but the Earth and Moon are a close-knit pair, and the Moon influences everything from our tides to our magnetic fields to the brightness of our nights. All life on Earth has evolved in the presence of the Moon, and so life on Earth can't be fully understood without considering our cosmic companion. In this episode, we discuss how the Moon influences life past and present, and what we know about the deep history of the...
May 01, 2022•2 hr 5 min•Ep. 201
We talk about fossils a lot on this podcast – every episode, in fact – but we rarely take the time to discuss how fossils get the way they are. This is a crucial subject, because the fossilization process is a filter, and nothing comes through the filter unaltered, and many things don’t come through at all. In this episode, we talk about how fossils typically form, how we study this process, and why it’s so important for paleontologists to understand fossilization. In the news: giant croc tracks...
Apr 17, 2022•1 hr 59 min•Ep. 200
Seahorses are very strange fish, with their upright posture, tube-like mouths, and various other unusual features. Along with their cousins in the family Syngnathidae, seahorses have been the subject of much research into how they came about their bizarre body plans and lifestyles. In this episode, we discuss a bit of what we know of how seahorses (and their relatives) do what they do, and how they came to do it. In the news: trilobite predators, early jaws, de-extinction troubles, and spinosaur...
Apr 03, 2022•2 hr 16 min•Ep. 199
Our highest-level supporters on Patreon get their own special mini-episode on a topic of their choosing! We released the first five in a compilation a while ago, and now that we’ve done five more, here’s another compilation for everyone to enjoy. Special thanks to our Patrons for their generous contributions, and thanks also to our special guest, Laura! 00:00:00 Intro 00:02:15 Crinoids for Lewis 00:16:15 Acrocanthosaurus for Will 00:36:30 The Hadean for Jordan 00:52:30 Fainting Goats for Mike 01...
Mar 28, 2022•1 hr 30 min•Ep. 198
Every plant starts somewhere, and often that somewhere is inside a seed. Seeds are among the most diverse and important evolutionary innovations of plants, allowing species to survive, thrive, and travel between generations in extraordinary ways. This episode, Aly joins us to discuss how seeds do what they do, how seeds have evolved over time, and how seeds are invaluable resources for paleontologists seeking to understand plants of the past. In the news: early octopus-cousins, early tuatara cou...
Mar 20, 2022•2 hr 30 min•Ep. 197
Paleoartist Rob Soto has created some fantastic artwork for the podcast over the years. Most recently, for our Five Year Anniversary celebration, he produced our Five Year logo and a series of movie-poster-style depictions of famous fossil localities, all now available on our merch store! In this special episode, we continue our Five Year celebration by sitting down with Rob to discuss his background in art and the process of creating the Art of Common Descent. Find Rob online: https://linktr.ee...
Mar 14, 2022•1 hr 48 min•Ep. 196
Blood is nutritious, easy to digest, and not hard to come by, so it’s unsurprising – if a bit unsettling – that thousands of species have evolved a taste for the stuff. From birds to bats to bugs, the diversity of sanguivores includes a wide variety of body plans, feeding strategies, and unique evolutionary histories, all converging upon a similar set of behaviors and features honed for a diet of blood. Be aware, this episode is, at times, kinda gross. In the news: a new spinosaur, a new pterosa...
Mar 06, 2022•2 hr 30 min•Ep. 195
None of us are alone. Like, in the literal, biological sense. Symbiotic relationships – close interactions between unrelated organisms – are a defining feature of life on Earth. Each of our bodies has its own share of parasites, hitchhikers, and tiny helpers, and some of the most prominent ecosystems on Earth function only by virtue of the symbiotic relationships at their foundations. In this episode, we touch on the incredible diversity and impact of symbiosis, and how the deep history of these...
Feb 20, 2022•2 hr 15 min•Ep. 194
Episode 132 – Mary and Louis Leakey Happy Darwin Day! Mary and Louis Leakey are two of the biggest names in the history of paleoanthropology and human evolution, and they’re one of history’s most impressive scientific duos. In this episode, our special guest takes us through the tales of the Leakey’s most important scientific work, their personal lives, and the ongoing impact they’ve had on modern science. Our guest this episode is Meredith Johnson, Communications Director at the Leakey Foundati...
Feb 06, 2022•2 hr 18 min•Ep. 193
Volcanoes are fascinating, devastating, and fundamental to Earth systems. Volcanic eruptions can transform ecosystems, landscapes, and even the atmosphere, and at their most extreme, the effects of volcanism can be global and long-lasting. In this overstuffed episode, we discuss the many forms and features of volcanic activity, and we take a look at the complex and dramatic interaction between volcanoes and life on Earth. In the news: ankylosaur brains, an Australian rainforest, donkey hybrids, ...
Jan 23, 2022•2 hr 56 min•Ep. 192
With every breath you take, you’re collecting information about your surroundings. We humans are actually pretty skilled smellers, as these things go, but olfactory abilities vary widely across the animal kingdom (and beyond). In this episode, we discuss how smelling works, what smelling is good for, and how scientists explore the evolutionary history of smell. In the news: giant ichthyosaurs, giant millipedes, long-tongued birds, and oviraptorid embryos. Time markers: Intro & Announcements:...
Jan 09, 2022•2 hr 17 min•Ep. 191
Happy New Year! Thanks as always to everyone who submitted questions for the Q&A. Thanks to everyone for listening, sharing, and supporting the podcast this year and for our whole run of nearly five years. We make the podcast, but you, our audience, make the podcast possible. More to come. See you in 2022. Check out our blog for bonus info and pictures: http://commondescentpodcast.wordpress.com/ Join us on Patreon to support the podcast and enjoy bonus content! https://www.patreon.com/common...
Dec 31, 2021•4 hr 5 min•Ep. 190
Today, rhinos are famous for their large size and impressive horns (and their distressing conservation status, sadly), but modern rhinos are only a small sample of what rhinos have been over time. Thanks to a surprisingly good rhino fossil record, we have a pretty good picture of how these animals got started and of the surprising forms they’ve taken since, from horse-like runners to hippo-shaped waders to gargantuan behemoths. This episode, we discuss rhinos as we know them, rhinos when they we...
Dec 26, 2021•2 hr 22 min•Ep. 189
Far below the ocean surface is a vast environment of cold, darkness, very scarce food, and surprisingly diverse life. Deep sea life is quite mysterious, in part because of their unusual adaptations for surviving in such tough habitats, and also because it’s very difficult to study organisms of the deep, modern or fossil. In this episode, we discuss what is known about the adaptations, evolutionary history, and diversity of life in the deep sea. In the news: blade-tailed ankylosaurs, ostrich-like...
Dec 12, 2021•2 hr 11 min•Ep. 188
Surprise! A special short(ish) episode of Silver Screen Science to discuss the Prologue/Trailer for Jurassic World: Dominion! Time markers: Science Discussion: 00:00 More Thoughts: 25:00 We're now taking questions for our End of the Year Q&A! Submit your question here: https://forms.gle/Q3jHtLSp5CdFuAuL9 Join us on Patreon to support the podcast and enjoy bonus content! https://www.patreon.com/commondescentpodcast Or make a one-time donation via PayPal: https://tinyurl.com/4c68u4hp Find merc...
Dec 04, 2021•33 min•Ep. 187
Located across a wide area of the Upper Great Plains of the United States, the Hell Creek Formation is one of the world’s premier locations for studying the Age of Dinosaurs, especially trends of evolution – and extinction – at the very end of the Mesozoic Era. In this episode, we discuss the ancient history and scientific history of the region, including some famous finds and groundbreaking research. In the news: giant ammonites, extinction beetles, baby pterosaurs, and the controversial Tetrap...
Nov 28, 2021•1 hr 49 min•Ep. 186
Evolution loves to plagiarize. You might be surprised at just how useful it can be for an organism to copy the signals, sights, sounds, and smells of others. Mimicry is all about making use of miscommunication. In this episode we’ll discuss the astounding diversity of modern mimics, the rare examples of fossil mimics, and the complex and confusing evolution patterns of mimicry. In the news: Cambrian bryozoans, early tusks, hermit worms, and parthenogenetic condors. Time markers: Intro & Anno...
Nov 14, 2021•2 hr 6 min•Ep. 185
Orchids are among the most diverse and widespread group of plants on Earth today, not to mention one of the most popular among plant enthusiasts. This episode, we discuss what makes orchids so unique and strange, as well as the many mysteries surrounding their evolution and deep history. As with all our plant episodes, Aly is on hand to tell us all about why orchids are so fascinating. Featuring special guest, Dr. Aly Baumgartner, our favorite paleobotanist! Follow Aly on Twitter or Instagram @p...
Oct 31, 2021•1 hr 48 min•Ep. 184
Welcome ... to Spookulative Evolution. October is here, and that means it’s time for Spook-E! Each episode throughout this month, we’re choosing a famous monster and discussing how it – or something like it – might evolve under the rules of evolution and natural selection, pulling inspiration from organisms of the real world. This year’s theme: monster plants. This episode, we face a more modern monster, star of page and screen. Can we invoke natural processes to develop a plant that haunts huma...
Oct 30, 2021•1 hr 5 min•Ep. 183
Welcome ... to Spookulative Evolution. October is here, and that means it’s time for Spook-E! Each episode throughout this month, we’re choosing a famous monster and discussing how it – or something like it – might evolve under the rules of evolution and natural selection, pulling inspiration from organisms of the real world. This year’s theme: monster plants. This episode, we evaluate a famous and deadly monster favored by healers and witches. How can we use nature’s toolkit to evolve a baby-sh...
Oct 23, 2021•48 min•Ep. 182
An Earth covered in ice might sound far-fetched, but there’s reason to think it has actually happened in the past – more than once. In this episode, we examine the Snowball Earth hypothesis and the geologic evidence and climate models that back it up, as well as some of the major lingering questions: Just how snowy is the snowball? How could this start? How could it end? And how did life fare on a frozen planet? In the news: ancient tardigrades, meat-eating sloths, shark communities, and relict ...
Oct 17, 2021•2 hr•Ep. 181
Welcome ... to Spookulative Evolution. October is here, and that means it’s time for Spook-E! Each episode throughout this month, we’re choosing a famous monster and discussing how it – or something like it – might evolve under the rules of evolution and natural selection, pulling inspiration from organisms of the real world. This year’s theme: monster plants. This episode, we ponder a familiar favorite of myths, media, and Middle Earth. What evolutionary path might result in a towering woody pl...
Oct 16, 2021•55 min•Ep. 180
Welcome ... to Spookulative Evolution. October is here, and that means it’s time for Spook-E! Each episode throughout this month, we’re choosing a famous monster and discussing how it – or something like it – might evolve under the rules of evolution and natural selection, pulling inspiration from organisms of the real world. This year’s theme: monster plants. This episode, we consider a classic category of plants-turned-monsters. How might natural selection produce a predatory plant with a tast...
Oct 09, 2021•1 hr 6 min•Ep. 179
Spiders are among the most diverse, successful, and famous living groups of invertebrates. Today, they’re a worldwide assortment of fascinating predators, and their scarce fossil record provides hints of a history over 300 million years old. In this episode, we discuss the diversity and evolution of spiders, their varied lifestyles, and their most versatile and famous tool, silk. In the news: snake evolution, giant penguins, early American humans, and spider parents. Time markers: Intro & An...
Oct 03, 2021•2 hr 1 min•Ep. 178
The Earth is in motion beneath our feet. The shifting and grinding of the tectonic plates is responsible for the shape of our planet’s surface and – directly or indirectly – nearly all the activity that happens upon it. Plate tectonics has a deep and fascinating history, both as a force that has shaped the Earth for billions of years and as a surprisingly recent foundational scientific theory. In the news: shark teeth, Cambrian predators, Carnotaurus skin, and teratorns. Time markers: Intro &...
Sep 19, 2021•2 hr 7 min•Ep. 177
Nearly all animals have some form of nervous system, and this system is often monitored and regulated by a brain. We humans are particularly proud of our enormous brains, but these organs come in all shapes and sizes across the animal kingdom, past and present. In this episode, we discuss brain diversity, the sometimes roundabout ways we explore brains in the fossil record, and what we’ve come to learn about the evolution of brains. In the news: turtle embryo, frog-legged leaf beetle, early liza...
Sep 05, 2021•2 hr 10 min•Ep. 176
Ever since T. rex was first identified in 1905, tyrannosaurs have been among the most famous and well-studied dinosaurs of all time. Research, especially in the last few decades, has revealed incredible details of tyrannosaur evolution, lifestyles, and development. This episode, we take a tour through tyrannosaur history, envision what these predators were like in life, and touch on some of the most prominent tyrannosaur controversies, including their notorious popularity. In the news: venom evo...
Aug 22, 2021•2 hr 51 min•Ep. 175
India is a landmass with an incredible history. Over the past half-billion years, it has spent time with the southern continents, time as an island-on-the-move, and time with the northern continents. Its fossil record is a combination of southern life, northern life, and uniquely Indian life, and its geologic history is not only the story of a traveling subcontinent, but also the origin story of one of Earth’s most impressive mountain ranges. In the news: baby pterosaurs, vampire bats, early spo...
Aug 08, 2021•1 hr 44 min•Ep. 174
As organisms live, grow, and move in their environments, they leave all sorts of traces in their surroundings, and these can become fossilized just like body parts can. Trace fossils (ichnofossils) can include evidence of burrowing, walking, feeding, and more. Individual trace fossils are great for understanding the behaviors of ancient organisms, and communities of trace fossils can help us track major changes in ecosystems through time. In the news: damaged cave bear, shrinking dinosaurs, koal...
Jul 25, 2021•2 hr 4 min•Ep. 173
What exactly is a “crab” anyway? One answer is that they are among the most diverse and successful living arthropods. Another answer: they are many different groups of crustaceans that have converged on a crabby body plan. In this episode, we discuss the diversity and evolution of “true crabs,” the incredible phenomenon of carcinization that keeps creating crabs, and what it really means to be a “crab.” In the news: poop beetles, Arctic dinosaurs, Dragon Man, and an ancient shark attack. Time ma...
Jul 11, 2021•1 hr 56 min•Ep. 172
