The Common Descent Podcast

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 mo...

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 o...

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...

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 “...

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...

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...

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:...

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...

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 micr...

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 f...

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 d...

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...

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 th...

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 fa...

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 die...

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...

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 evol...

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 inc...

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...

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 & Announce...

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_desc...

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 trigg...

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 b...

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 s...

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 Patre...