The history of evolution has seen many land animals move to the sea, but few have done it with such success and specialization as ichthyosaurs. These Mesozoic marine reptiles were the first group of tetrapods to truly dominate the marine realm, and they evolved some of the most extreme adaptations – and largest bodies – of any ocean-dwelling tetrapods. This episode, we discuss how they got started, what they did, where they went, and why they’re so incredibly famous. In the news: giant crocs, gi...
Jun 27, 2021•2 hr 11 min•Ep. 171
This June, by popular demand, we’re doing a Silver Screen Science double feature focusing on our two favorite reptiles: crocs and snakes. One croc movie, one snake movie, both quintessential creature features of the 90s. This episode, it’s snake time: Anaconda (1997) The Common Descent Store is open! Get merch! http://zazzle.com/common_descent Follow and Support us on: Patreon: https://www.patreon.com/commondescentpodcast Twitter: https://twitter.com/CommonDescentPC Facebook: https://www.faceboo...
Jun 24, 2021•1 hr•Ep. 170
This June, by popular demand, we’re doing a Silver Screen Science double feature focusing on our favorite reptiles: crocs and snakes! One croc movie, one snake movie, both quintessential creature features of the 90s. This episode, crocs take center stage: Lake Placid (1999) Next time … Anaconda. The Common Descent Store is open! Get merch! http://zazzle.com/common_descent Follow and Support us on: Patreon: https://www.patreon.com/commondescentpodcast Twitter: https://twitter.com/CommonDescentPC ...
Jun 17, 2021•51 min•Ep. 169
All over the Earth, there are biological communities that differ depending on the local climate and landscape. These are biomes, and biologists love to map them to unravel patterns of ecosystem distribution. But biomes also change over time as climates and landscapes shift. In this episode, our favorite paleobotanist, Dr. Aly Baumgartner, joins us to discuss how we identify biomes in the past and present, how they’ve changed over time, and what it means for a new biome to arise … or for an old o...
Jun 13, 2021•1 hr 53 min•Ep. 168
Far to the north and far to the south, conditions on Earth get weird. Cold climates and periods of perpetual night or day create some of the most unique habitats on the planet. In this episode, we look at what makes the polar regions so strange, how they’ve changed over time, what it takes for life to survive there, and what fossils tell us about what lived there in the past. In the news: gut microbiomes, chewed Neanderthals, ancient symbiosis, and very old turtles. Time markers: Intro & Ann...
May 30, 2021•1 hr 59 min•Ep. 167
The geologic record of Earth is an archive of data on the causes and effects of changing climates. As climate changes, it impacts everything from plants and animals to rocks and rivers. The study of ancient climates is paleoclimatology, and it’s important not only for our understanding of climate in the past, but also for teasing out what’s happening with our climate today and what we can expect for the future. In the news: tyrannosaur group, a chomped squid, horned crocs, and night dinosaurs. T...
May 16, 2021•2 hr 18 min•Ep. 166
Subterranean passages and chambers within the Earth form eerie and incredible environments that are home to unique ecosystems of bizarre creatures and which serve as some of the most invaluable sources of fossils in the world. This episode, we discuss how caves form, what ecosystems dwell within them, and why they’re so darn important for paleontology. In the news: pterosaur thumbs, scimitar-cat diets, counting T. rex , and ancient soil DNA. Time markers: Intro & Announcements: 00:00:00 News...
May 02, 2021•2 hr 2 min•Ep. 165
There isn’t much on Earth quite like an ant colony or a beehive. Lots of animals are social, but relatively few are eusocial. It’s a bizarre lifestyle, living in large multi-generational colonies with lots of members who don’t reproduce but instead dedicate their lives to protecting and nourishing the offspring of the few reproducers. In this episode, we discuss the many questions surrounding this phenomenon, including how many times this trait has evolved, why it’s apparently so beneficial, and...
Apr 18, 2021•2 hr 10 min•Ep. 164
We’ve talked a lot about Godzilla and King Kong in previous Silver Screen Science episodes, and now there’s a new movie with both of them in it, so we’re going to talk about that! More monster fights, more science, more fun. This episode, the all-star monsters are back: Godzilla vs. Kong (2021) We also briefly discuss the last time these monsters met: King Kong vs. Godzilla (1962) Find merch at the Common Descent Store! http://zazzle.com/common_descent Follow and Support us on: Patreon: https://...
Apr 12, 2021•1 hr 1 min•Ep. 163
Go searching in the right spots in Illinois and you’re liable to find a hard chunk of ironstone with a gorgeous fossil inside. The Mazon Creek Fossil Beds represent some of the best Carboniferous fossils in the world, yielding exceptionally preserved plants and animals from a tropical river delta over 300 million years old. This episode, we discuss the history, the geology, and some of the most famously bizarre creatures of Mazon Creek. In the news: a “winged” shark, digging ankylosaurs, the old...
Apr 04, 2021•1 hr 29 min•Ep. 162
Despite their unfortunate reputation, hyenas are really impressive. Modern and fossil, they’re a diverse group with a variety of dietary and social habits, and they are the quintessential example of bone-crushing specialists. In this episode, we discuss what makes hyenas unique and interesting, and we take a look at their surprisingly varied fossil history. In the news: lamprey larvae, octopus diets, nesting dinosaurs, and tyrannosaur bites. Time markers: Intro & Announcements: 00:00:00 News...
Mar 21, 2021•1 hr 59 min•Ep. 161
Penguins aren’t the only flightless birds, and they aren’t the only diving birds, but they sure are good at doing both! In this episode, we discuss modern penguins’ unique suite of adaptations that allow them to spend so much of their lives in the water, and then we address some of the most pressing questions about their past: How did they get their start? What drove their evolution? And why were some of them so disconcertingly large? In the news: giant coelacanths, really old DNA, fossil vampir...
Mar 07, 2021•1 hr 59 min•Ep. 160
Taking teeth to the extreme! Tusks have evolved numerous times, particularly in mammals, and they’ve come in a striking array of shapes and sizes for a variety of uses. From the monstrously huge ivory tusks of mammoths to the modest yet effective tusks of fanged deer to the bizarre and perplexing tusks of babirusas and narwhals, in this episode we discuss trends, drivers, and mysteries in the evolution of tusks. In the news: razor-toothed mosasaurs, walk the dinosaur, sidewinder skin, and really...
Feb 21, 2021•2 hr 4 min•Ep. 159
Happy Darwin Day! Baron Franz Nopcsa was a paleontologist around the start of the 20th Century, remembered today for his innovative fossil research, his (in)famous personality, and his fantastic adventures across Eastern Europe. In this episode, we’ll discuss how this aristocrat became a paleontologist and how he contributed to our modern understanding of dinosaurs, and we’ll share some of the incredible and bizarre stories that surround him. In the news: Parasaurolophus crests, sand striker bur...
Feb 07, 2021•1 hr 56 min•Ep. 158
A new tradition begins! Get ready for more plants with our friend Dr. Aly Baumgartner! Most plants are content to sit still and take in sunlight and soil nutrients, but when conditions are tough, some plants get hungry! The habit of devouring small animals has evolved in plants several times. In this episode, we discuss what counts as carnivory in plants, why they do it, the various methods plants use to murder their meals, and what little we know about the evolutionary history of this behavior....
Jan 24, 2021•2 hr 12 min•Ep. 157
Seals, sea lions, and walruses (oh my!) are widespread, successful, and invariably charming. In this episode, we take a look at how they’re adapted for their aquatic lifestyles and how they might have gotten that way. We’ll explore some of the unanswered questions about their origins and evolution, and we’ll take a tour through their diverse but spotty fossil record. Time markers: Intro & Announcements: 00:00:00 News: 00:04:00 Main discussion, Part 1: 00:29:00 Main discussion, Part 2: 00:57:...
Jan 10, 2021•1 hr 42 min•Ep. 156
Happy New Year! A huge thanks to everyone who sent in questions for this year’s Q&A – we got more than we could even answer! – and to everyone who has supported the podcast this year by listening, sharing, donating, and reaching out to us. Check out our blog for bonus info and pictures: http://commondescentpodcast.wordpress.com/ Find merch at the Common Descent Store! http://zazzle.com/common_descent Follow and Support us on: Patreon: https://www.patreon.com/commondescentpodcast Twitter: htt...
Dec 31, 2020•3 hr 47 min•Ep. 155
The PETM has been called the largest natural climate change event of the Cenozoic Era. It marks the transition from the ecosystems of the Paleocene to the more familiar world of the Eocene and is thus an important step in making the world the way we know it today. But maybe most importantly, it is a dramatic case study in what happens when a huge amount of Carbon injected into the atmosphere triggers rapid warming of global climate … you know, in case anyone needs to know about that. In the news...
Dec 27, 2020•1 hr 45 min•Ep. 154
The word parasite doesn’t typically invoke a lot of happy thoughts for us humans, but as far as life on Earth is concerned, parasitism is a path to success. As we discuss in this episode, an incredible diversity of organisms, past and present, have developed an equally incredible diversity of strategies for stealing, siphoning, and exploiting resources from other organisms. In the news: surprise bird beak, alligator tails, flightless birds, and chemical re-assessment. Time markers: Intro & A...
Dec 13, 2020•2 hr 3 min•Ep. 153
Is there a group of dinosaurs more iconic than sauropods? Famous for their ridiculously long necks, their global success, their astounding diversity, and of course for their unparalleled size, sauropods have fascinated and puzzled people for centuries. In this episode, we’ll explore what makes sauropods and their ancestors special, and we’ll talk a bit about how they functioned at truly colossal scales. In the news: strange-jawed sharks, ancient walruses, dinosaur demise, and the oldest blindsna...
Nov 29, 2020•1 hr 53 min•Ep. 152
We’ve released 100 episodes of the podcast! Plus, more than 50 side episodes, a handful of YouTube videos, some live shows … it’s been quite a journey. In this episode, we take some time to look back over our experience, to discuss some of our favorite aspects of the podcast, and above all, to thank our listeners. Thank you. To everyone who listens to the podcast; everyone who supports us on Patreon; everyone who sends us requests, questions, comments, and feedback; everyone who follows us on so...
Nov 22, 2020•1 hr 8 min•Ep. 151
One hundred episodes is kind of a big deal, so we figured we’d pick a big deal kind of topic, and it doesn’t get much bigger than this. As far as we can tell, all life on Earth is descended from a common ancestry – at some point, at least once, life originated on Earth. But when, where, and how? These are open questions that have been subject to lots of scientific and philosophical discussions and experiments. In this episode, we’ll touch on some of the biggest questions: What even is life? How ...
Nov 15, 2020•2 hr 40 min•Ep. 150
Insects must be among the most impressive animals in Earth history. For hundreds of millions of years, they have been some of the most significant animals on land in terms of their abundance, diversity, and ecological impact. Their deep story is marked by evolutionary innovations that weren’t just major events for insects, but major events for the entire planet. This episode, we barely scratch the surface of the insect story. In the news: a new pterosaur, big Antarctic birds, gliding dinosaurs, ...
Nov 01, 2020•2 hr 4 min•Ep. 149
Welcome ... to Spookulative Evolution. It’s October once again and time for Spook-E! Each episode throughout this month, we’re choosing a monster and discussing how it – or something like – might evolve biologically, pulling inspiration from critters of the real world. This month’s theme: sea monsters. This episode, we turn our attention to the creatures whose enticing songs sound over the sea. How can we naturally evolve a group of humanoid(ish) island-dwellers whose voices lure in victims? Our...
Oct 31, 2020•51 min•Ep. 148
Welcome ... to Spookulative Evolution. It’s October once again and time for Spook-E! Each episode throughout this month, we’re choosing a monster and discussing how it – or something like – might evolve biologically, pulling inspiration from critters of the real world. This month’s theme: sea monsters. This episode, we explore a monster whose name is synonymous with immensity and might. What biological history could explain a dangerous sea giant worthy of divine association? Our creature to crea...
Oct 24, 2020•55 min•Ep. 147
When we study life, past or present, we talk a lot about species, their evolution, their diversity, their extinction, and more. But we don’t often slow down to discuss what we really mean by that. What is a species? How and where do new species arise? It turns out this topic is much more complicated – and controversial! – than it may seem. In this episode, we’ll touch on the basics and discuss why scientists get so worked up about species and speciation. In the news: a glass-ified brain, a Creta...
Oct 18, 2020•2 hr 3 min•Ep. 146
Welcome ... to Spookulative Evolution. It’s October once again and time for Spook-E! Each episode throughout this month, we’re choosing a monster and discussing how it – or something like – might evolve biologically, pulling inspiration from critters of the real world. This month’s theme: sea monsters. This episode, we tackle a particularly prevalent body shape among sea monsters. How might evolution produce an ocean full of enormous slithery beasts fit for sailors’ nightmares? Our creatures to ...
Oct 17, 2020•58 min•Ep. 145
Welcome ... to Spookulative Evolution. It’s October once again and time for Spook-E! Each episode throughout this month, we’re choosing a monster and discussing how it – or something like – might evolve biologically, pulling inspiration from critters of the real world. This month’s theme: sea monsters. This episode, we discuss one of the most famous fictional sea creatures of all. How might natural selection give us a ship-wrecking cephalopod of titanic proportions? Our creature to create this t...
Oct 10, 2020•1 hr 2 min•Ep. 144
Okay, that’s not a great title. More accurately, we’re discussing toxins, the substances that organisms produce for chemical defense or attack against each other. Toxins are found in practically all living things, they function as part of immune systems, poisonous defenses, and predatory venom, and they have all sorts of amazing effects from discomfort to death. In this episode, we’ll touch on who has them, what they do, and what we know about the long, complex evolutionary history of venom and ...
Oct 04, 2020•1 hr 55 min•Ep. 143
Marsupials are like alternate-reality mammals. Everything about them, from their skeletons to their reproductive strategies, is just a bit strange – from the perspective of us placental mammals, that is! But you can’t argue with results, and marsupials include some of the most fascinating mammals of the past and present. In this episode, we track the long evolutionary journey that gave the modern world its kangaroos, koalas, possums, opossums, and more. In the news: air-breathing sea scorpions, ...
Sep 20, 2020•2 hr 8 min•Ep. 142
