Podcasts about cretaceous paleogene

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Best podcasts about cretaceous paleogene

Latest podcast episodes about cretaceous paleogene

Palaeo After Dark
Podcast 308 - Failing to Talk About the K/Pg Mass Extinction

Palaeo After Dark

Play Episode Listen Later May 18, 2025 105:05


The gang tries to discuss two papers that look at the evolutionary impacts of the K-Pg mass extinction. Specifically, they look at one paper that estimates sampling probability throughout the late Cretaceous to determine if record bias influences our understanding of the extinction, and another paper that looks at species area relationships to investigate ecological shifts in response to the event. However, the gang gets completely lost and sidetracked throughout. They starting talking about the papers around 18 minutes in… and very quickly lose track again. It's going to be one of those podcasts.   Up-Goer Five (Curt Edition): The friends do a real bad job of talking about two papers that look at what happened when a big rock fell from the sky a long time ago. The first paper looks at the rocks we have from that time and tries to see how well we know what was happening and what was going on with the animals that were around at that time. Given the rocks we have, how sure are we that we know where animals were and how many of those things were around. It turns out that just before the big rock hit, we do not have a good idea of what things were around and where they were. The second paper looks at how the places where things were living in the past changed before and after the big rock hit. The idea is that some animals may have done well because they could go to all of the places when things get bad because they do well when things go bad. This paper says that this is not happening and that there is way more going on with these groups that were doing well after the big rock hit.   References: Close, Roger Adam, and Bouwe Rutger Reijenga. "Tetrapod species–area relationships across the Cretaceous–Paleogene mass extinction." Proceedings of the National Academy of Sciences 122.13 (2025): e2419052122. Dean, Christopher D., et al. "The structure of the end-Cretaceous dinosaur fossil record in North America." Current Biology (2025).

Strange Animals Podcast
Episode 417: The Hoatzin

Strange Animals Podcast

Play Episode Listen Later Jan 27, 2025 9:37


I'm a bit under the weather this week, so here's a Patreon episode about a weird bird! Further reading: Hoatzin nestling locomotion: acquisition of quadrupedal limb coordination in birds Show transcript: Welcome to the Patreon bonus episode of Strange Animals Podcast for mid-November, 2019! We're going to learn about a mystery bird today. When I say mystery bird, I don't mean that people aren't sure if it exists. It definitely exists. You can go to South America and look at it if you like, because fortunately it's not rare or endangered. But scientists aren't completely sure what it's related to, because it's a really weird bird. The hoatzin [pronounced what-seen] is a large bird, over two feet long, or 65 cm. It's shaped sort of like a pheasant, with a chunky body, long neck and small head, and a long tail made of stiff feathers like a hawk's. Its face has no feathers and blue skin, it has red eyes, and it has a spiky feather crest on its head. It's black and chestnut brown with some darker and lighter streaks, and is a softer brown underneath. It's a really pretty bird, in fact, with a strong bill. But it really doesn't resemble any other bird alive today. The hoatzin is the only species in its genus, and the only genus in its family, and the only family in its order. It's basically not really related to any other bird alive today, although in 2012 its genome was sequenced and found to be most closely related to cranes and plovers—but only very distantly. In fact, a 2015 study determined that the hoatzin started evolving separately from other birds 65 million years ago, right after the Cretaceous-Paleogene extinction event that killed off the non-avian dinosaurs. We only have a few fossils of hoatzin ancestors, but they show that it was much more widespread in the past and lived in what is now North America and Europe. But these days it only survives in northern and central South America. It likes swampy areas and forests near rivers or other water. The hoatzin eats plants—specifically leaves and buds, although it also eats some flowers and fruit. And leaves require a lot of digesting before the body can make use of the nutrients. The hoatzin's digestive system is unlike any other living bird's, because the hoatzin is a foregut fermenter. Its crop, which most birds only use to store extra food temporarily when the stomach is full, acts as a bacterial fermentation chamber—two chambers, in fact, since it's divided into two sections. This acts like the rumen of a cow. Its crop is so big it doesn't have room on its body for big flight muscles, so it's not a strong flyer. It mostly stays in trees and bushes, eating leaves, flapping its big wings for balance and display, and hanging out with other hoatzins. The hoatzin's digestive system has a weird side effect. It smells bad. It's supposed to smell like manure. It's sometimes called the stinkbird and, fortunately for the hoatzin, almost no one wants to eat it as a result. As you probably know, birds developed from dinosaurs. It's easy to forget that, since birds have evolved structures like toothless beaks and front legs modified for flight and they no longer have lizard-like tails. But the hoatzin retains something from its dinosaur ancestry that is a startling reminder. The hoatzin is a social bird that lives in small flocks. It breeds during the local rainy season and builds its nest over water when the forest floods due to rain. The female lays two or three eggs, and when the babies hatch, they can climb around in the branches near the nest right away. This means they can hide from predators instead of being helpless in the nest. And the reason a hoatzin chick can climb so well is partly because it has big feet, and partly because it has finger claws on its wings: specifically a thumb claw and one finger claw, which are fully functional and make it look a lot like a fuzzy baby dinosaur.

RiYL
Episode 613: Riley Black

RiYL

Play Episode Listen Later Nov 8, 2023 61:07


Sixty-six million years ago, roughly three-quarters of the Earth's plants and animals went extinct. As Riley Black notes, such deaths happened almost instantaneously. Those who survived asteroid impact perished shortly after. The Cretaceous–Paleogene extinction event is the cheery topic that forms the basis of Black's best-selling, The Last Days of the Dinosaurs. She joins us to discuss her path to paleontology and the experience navigating the field as a trans woman. Hosted on Acast. See acast.com/privacy for more information.

Stormy Willow
E78 Reptilians

Stormy Willow

Play Episode Listen Later Sep 25, 2023 62:35


More commonly known as lizard-people. Are these beings ancient survivors of the Cretaceous-Paleogene extinction event or something far more sinister?

reptilians cretaceous paleogene
PaperPlayer biorxiv cell biology
Thermosensitivity of translation underlies the mammalian nocturnal-diurnal switch

PaperPlayer biorxiv cell biology

Play Episode Listen Later Jun 22, 2023


Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.06.22.546020v1?rss=1 Authors: Beale, A. D., Rzechorzek, N. M., Mihut, A., Zeng, A., Smyllie, N. J., Pilorz, V., Richardson, R., Bertlesen, M. F., James, N. R., Fazal, S. V., Voysey, Z., Pelletier, J., Crosby, P., Peak-Chew, S. Y., Lancaster, M. A., Hut, R. A., O'Neill, J. S. Abstract: Early mammals were nocturnal until the Cretaceous-Paleogene extinction facilitated their rapid expansion into daytime niches. Diurnality subsequently evolved multiple times, independently, but the mechanisms facilitating this switch are unknown. We found that physiological daily temperature shifts oppositely affect circadian clock rhythms in nocturnal versus diurnal mammals. This occurs through a cell-intrinsic signal inverter, mediated by global differences in protein phosphorylation, and effected at the level of bulk protein synthesis rates, with diurnal translation rate being less thermosensitive than nocturnal. Perturbations that reduce translational initiation or mTOR activity are sufficient to trigger the nocturnal-to-diurnal switch at the cellular, tissue, and organismal scale. Our results suggest a convergent selection pressure to attain diurnality by reducing the effect of temperature-dependent changes in protein synthesis on circadian clocks. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Jurassic Park Cast
Episode 42 - Control PART A

Jurassic Park Cast

Play Episode Listen Later Feb 16, 2023 82:10


Welcome to the Juras-Sick Park-Cast podcast, the Jurassic Park podcast about Michael Crichton's 1990 novel Jurassic Park, and also not about that, too.  Find the episode webpage at: Episode 42 - Control. In this episode, my terrific guests Garret and Sabrina of I Know Dino join the show to chat with me about: cool musuems around the world, visiting Canada, the ROM's Dawn of Life Gallery, reporting on SVP, podcasting, pronouncing dinosaur names, enjoying Jurassic Park the novel and the film, raptors in the kitchen, gallimimus stampeding, Alan Grant's character development, the resounding presence of the film, dinosaurs news!, enantiornithines and siledesauridae and ... seriously, check out Tom Holtz Jr.'s Twitter feed for dinosaur news - it's authoritative!, but also, visit and enjoy I Know Dino, Stegouros elengassen, soft tissues and gut contents, paleopathologies, the Crystal Park Dinosaurs, and much more!   Plus dinosaur news about: Early Evolution of Modern Birds Structured by Global ForestCollapse at the End-Cretaceous Mass Extinction New materials of the Early Cretaceous spinosaurid (Theropoda) teeth of Napai Basin, Fusui County, Guangxi Featuring the music of Snale https://snalerock.bandcamp.com/releases  Intro: Atom-Age Vampire-Cat In The Brain.  Outro: Hummingbird. The Text: This week's text is Control, spanning from pages 228 – 233. Synopsis: John Arnold and Henry Wu search through the computer system to figure out what Dennis Nedry has done to the operating systems at Jurassic Park. They discover wht_rbt.obj, a command disguised as an object, that was Nedry's trap door that links the security and perimeter systems and then turns them off, giving him complete access to every place in the park.  Discussions surround: Show Don't Tell; Timeline; and Similarities and Differences with the film;  Corrections: KPg stands for the Cretaceous-Paleogene boundary, not the Cretaceous-Cenozoic boundary.    Side effects:  May cause a severe case of wanderlust to explore museums both near and far.  Find it on iTunes, on Spotify (click here!) or on Podbean (click here). Thank you! The Jura-Sick Park-cast is a part of the Spring Chickens banner of amateur intellectual properties including the Spring Chickens funny pages, Tomb of the Undead graphic novel, the Second Lapse graphic novelettes, The Infantry, and the worst of it all, the King St. Capers. You can find links to all that baggage in the show notes, or by visiting the schickens.blogpost.com or finding us on Facebook, at Facebook.com/SpringChickenCapers or me, I'm on twitter at @RogersRyan22 or email me at ryansrogers-at-gmail.com.  Thank you, dearly, for tuning in to the Juras-Sick Park-Cast, the Jurassic Park podcast where we talk about the novel Jurassic Park, and also not that, too. Until next time!  #JurassicPark #MichaelCrichton

Mod Stjernerne
Mod Stjernerne - Episode 65 - Artemis 1 letter snart, Andreas Mogensens mission får navn og logo, og nyt krater fundet ud for Afrika

Mod Stjernerne

Play Episode Listen Later Aug 26, 2022 30:14


I dette afsnit snakker Hasse og Lasse om Artemis 1 som skal lette mod Månen den 29. august, Andreas Mogesen fik præsenteret navnet og mission patchet på sin kommende mission til ISS. Vi runder også lige Brevkasse med Hasse og Lasse hvor der er hele 2 spørgsmål, samt en tur til Afrika hvor forskere mener de har fundet nedslagskrateret for en pænt stor asteroide.    Artemis 1 opsendelse (29/8/2022, 14:33, dansk tid) NASA Live | NASA Andreas mission:  ESA - Introducing Huginn James Webb spikes i stjerner: Why Do The Stars In The Webb Telescope's First Images Have Eight Weird ‘Snowflake' Spikes? (forbes.com) Krater ud for Afrikas kyst: The Nadir Crater offshore West Africa: A candidate Cretaceous-Paleogene impact structure | Science Advances

Zimmerman in Space
#224 - De Nadir krater

Zimmerman in Space

Play Episode Listen Later Aug 24, 2022 17:30


De vondst van een steenoude krater - of althans, wat daar van over is - werpt een nieuw licht op de ontstaansgeschiedenis van onze aarde.  Het element iridium: https://en.wikipedia.org/wiki/Iridium (https://en.wikipedia.org/wiki/Iridium) Een plaatje van de Chicxulub krater: https://commons.wikimedia.org/wiki/File:Chicxulub.jpg Crater Explorer: https://craterexplorer.ca/chicxulub-impact-structure/ The Nadir Crater offshore West Africa: A candidate Cretaceous-Paleogene impact structure: https://www.science.org/doi/10.1126/sciadv.abn3096 Tres Amicis maankraters: http://lroc.sese.asu.edu/posts/519 International Ocean Discovery Program: https://www.iodp.org/

nadir iridium krater chicxulub cretaceous paleogene
The Breakdown with Aaron Barker
Selfie Imposed Extinction

The Breakdown with Aaron Barker

Play Episode Listen Later Mar 15, 2022 1:31


Humanity is heading toward the sixth mass-extinction event. Better stock up on that Spam. Let's break it down.Scientists are claiming we are accelerating the sixth mass extinction event, driven by the industrial revolution. According to historical scientists, mass extinction events took place several millions years apart. These events were brought about by volcanoes, the formation of mountains, the ice age, and the most famous of all - the Cretaceous-Paleogene extinction. An asteroid over 8 miles in diameter purportedly hit the earth at 45,000 miles per hour, ending the reign of the dinosaurs. Glaringly absent from all these past events is, you guessed it - human beings. One wonders how humanity can be blamed for our current circumstances, when the first five mass extinctions happened sans evil capitalists trying to get to third base with Mother Earth.If these globe humper's would express a modicum of intellectual honesty, I could get on board. But with the "Survival of the fittest" on the table, should it really concern evolutionists when stronger species take over a specific domain?To reverse this impending planetary doom, blame must be appropriated correctly. Can't we all agree that the annihilation of most species on earth is catalyzed by millennial's with their incessant use of emoji's and their gourmet soy latte orders? If it wasn't for these beatniks milking every nut known to man while taking a blue million duck-lip selfies, we might, could stave off global catastrophe.Be sure to purse your lips in that perfect selfie with the Sweet Meteor of Death while sipping on your Double-iced-skinny-mocha-soymilk extra froth latte Grande in a Venti cup.Get more at https://breakdradio.com/Listen to MoJo 5-0: https://www.mojo50.com/Listen to Odysy Radio: https://www.odysyradio.com/

ThePrint
PureScience: Dino asteroid struck in spring, killing northern hemisphere post-hibernation life more

ThePrint

Play Episode Listen Later Feb 25, 2022 9:58


From studying six fish fossils at Tanis, the famous site that documents mass floods from the Cretaceous-Paleogene extinction event, scientists have concluded that the asteroid impact that killed the dinosaurs and 75% of life occurred in the spring season. This was particularly deadly for animals in the Nothern Hemisphere that were coming out of hibernation, but autumn at the Southern Hemisphere and animals stepping into hibernation aided the recovery in this half of the world. ThePrint's Sandhya Ramesh explains. Brought to you by  @Kia India  ----more----Subscribe to the Pure Science Telegram Channel https://t.me/PureScienceWithSandhyaRamesh----more----Supplementary reading: During et al., The Mesozoic terminated in boreal spring. Nature (2022). https://doi.org/10.1038/s41586-022-04446-1----more----DePalma et al., Seasonal calibration of the end-cretaceous Chicxulub impact event. Scientific Reports (2021) https://doi.org/10.1038/s41598-021-03232-9 ----more----New Yorker | The Day the Dinosaurs Died (2019), Douglas Preston. https://www.newyorker.com/magazine/2019/04/08/the-day-the-dinosaurs-died----more----Schulte et al., The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene Boundary. Science (2010) https://www.science.org/doi/10.1126/science.1177265

The Nonlinear Library
EA - Risks from Asteroids by finm

The Nonlinear Library

Play Episode Listen Later Feb 13, 2022 12:17


Welcome to The Nonlinear Library, where we use Text-to-Speech software to convert the best writing from the Rationalist and EA communities into audio. This is: Risks from Asteroids, published by finm on February 11, 2022 on The Effective Altruism Forum. When thinking about risks from space, you'll likely think of comets and asteroids. The asteroid that caused a mass extinction event approximately 66 million years ago collided with an energy roughly ten billion times as great as the bomb dropped on Hiroshima. Far more significant than the damage caused directly by the impact, it caused a cloud of ash and dust to block out the Sun's light across the globe — eventually rendering three quarters of the world's species extinct. As recently as 1908, an asteroid exploded over a region of remote Siberia, flattening an estimated 80 million trees over more than 2,000 km2 of forest. There is no impact crater; instead the meteoroid likely disintegrated kilometers above the ground in an ‘air burst' — powerful enough to throw people to the ground as far as 40 miles from the centre of the explosion. If a similar-sized asteroid instead exploded over a large metropolitan area, it might have killed more people in a single day than any event in history. Worse still, an asteroid greater than 10km in diameter colliding with Earth could massively disrupt Earth's climate, likely causing a long ‘winter' making it far harder to grow crops. The result could be the premature deaths of most living people, human progress thrown back by decades, or perhaps — given some mechanism by which survivors would fail to repopulate — permanent extinction. So wouldn't the space programs of the world do well to urgently unite around building effective asteroid defence systems? The answer isn't so clear. First, we know that catastrophic asteroid impacts must be very infrequent, and asteroids that pose significant existential risks like extinction are even rarer. Without even trying to count asteroids in the night sky, we can look at the Earth for indications of large craters or extinction events, and reason that asteroids over 1km in diameter can't strike much more frequently than once every million years on average — any higher and the relatively small number of craters wouldn't make sense. Of course, we can also try to spot asteroids in the sky. Astronomers have identified a large majority of near-Earth asteroids larger than 1km across, and many smaller examples. From these surveys, we know that the chance of an Earth-impact for asteroids 1-10km in diameter is about 1 in 6,000, and about 1 in 1.5 million for asteroids larger than 10km across — that is, roughly the size of the asteroid that caused the Cretaceous–Paleogene mass (dinosaur) extinction event. But we can be even more confident about the risk from asteroids in this century specifically, because astronomers can track the large asteroids they spot and check whether their trajectories are on course to intercept with Earth's. With this more precise information, the risks look lower still. In particular, the chance of an impact from an asteroid greater than 10km in size following its natural orbit is effectively zero if NASA is correct in claiming it has identified all asteroids this size. In The Precipice, Toby Ord summarises the risks: Asteroid sizeTotalFoundAverage CenturyNext Century1-10 km~ 920~ 95%1 in 6,0001 in 120,00010 km~ 4> 99%1 in 1.5 million< 1 in 150 million Spotting and tracking asteroids is important: knowing whether they pose a risk this century means knowing more about how best to allocate our resources across different kinds of risk. Very likely, we needn't worry about building asteroid defence until the deflection technology is cheaper, more effective, and easier to govern; but there's a slim chance we may need an all-out effort on deflection now because we spot an asteroid heading our way. Clearly, it pays to know which world we're in. Fortunately, the international community has already d...

The Nonlinear Library: EA Forum Top Posts
Pangea: The Worst of Times by John G. Halstead

The Nonlinear Library: EA Forum Top Posts

Play Episode Listen Later Dec 11, 2021 16:02


Welcome to The Nonlinear Library, where we use Text-to-Speech software to convert the best writing from the Rationalist and EA communities into audio. This is: Pangea: The Worst of Times, published by John G. Halstead on the AI Alignment Forum. 260 million years ago, our planet had an unfamiliar geography. Nearly all of the landmasses were united into a single giant continent known as ‘Pangea' that stretched from pole to pole. On the other side of the world you would find a vast ocean, even larger than the present Pacific, called Panthalassa. The Pangean era lasted 160 million years, and 80 million of these were extremely inhospitable to animal and plant life, coinciding with two mass extinctions and four other major extinction events. This is why Paul Wignall, a Professor of Palaeoenvironments at Leeds has called the Pangean era ‘The Worst of Times'. Understanding why the Pangean era was so miserable helps inform several questions of interest to those studying existential risk. ● What level of natural existential risk do we face now, and have we faced in the past? ● What is the threat of super-volcanic eruptions? ● How much existential risk does anthropogenic climate change pose? 1. Background There have been five mass extinctions so far. The Ordovician–Silurian (450-440 million years ago) and the Late Devonian (375-360 million years ago) each preceded the age of Pangea. The Pangean period coincided with the two worst mass extinctions, the huge Permian-Triassic mass extinction (252 million years ago) and the Triassic-Jurassic extinction event (201 million years ago).[1] The last crisis, the Cretaceous–Paleogene event (65 million years ago), accounted for the dinosaurs and occurred once continental drift had done its business and Pangea had broken apart. With the exception of the end Cretaceous extinction, since the breakup of Pangea, it has been relatively plain sailing for Earth's various species, until humans started killing off other species themselves. [2] As one can see on this diagram, in the 145 million years since the start of the Cretaceous, the average rate of global genus extinctions from extinction events has been around 5% and never passed 15%, except for the death of the dinosaurs. But in the 80 million years from the first Pangean extinction event, the Capitanian, to the early Jurassic extinction events, the average rate of global genus extinctions in extinction events is more around 15-20%, and 12 events produced global genus extinction rates in excess of 15%. Below is a useful chart from Wikipedia on the Phanerozoic, which shows the long-term trend in biodiversity as well as the impact of different extinction events. Again, this highlights how unusually bad things were in the Pangean era - specifically the 80 million years after the Capitanian extinction event 260 million years ago. But it also highlights how good things have been since the end of the Pangean era and the start of the Cretaceous (145 million years ago). 2. What caused such ecological trauma in Pangea? Huge volcanic eruptions were implicated in all of the six major extinction events in the Pangean era. One can see this in the first diagram above, where the volcanic eruptions are shown at the top and the line traces down to corresponding extinction events at the bottom. Every Pangean extinction event coincided with the outpouring of enormous fields of lava that, once cooled, produced what geologists call Large Igneous Provinces (LIPs).[3] To put these LIPs in context, the eruption of Mount Pinatubo in 1991 produced 10 cubic km of magma, which caused the Earth to cool by about half a degree. The eruption of the Siberian Traps which appeared to cause the end Permian extinction produced 3 million cubic km of magma. You can see the volume of magma for all major LIPs at the top of the first diagram above. These volcanic eruptions emitted sulphur dioxide, carbon dioxide and halogen gases, each of which could potentially have an effect on the ecosys...

earth professor speech wikipedia pacific ea leeds lips jurassic pangea cretaceous john g halstead permian rationalist mount pinatubo phanerozoic cretaceous paleogene late devonian permian triassic panthalassa triassic jurassic
45 Graus
#109 Octávio Mateus - Dinossauros, evolução, História da vida na Terra & mais

45 Graus

Play Episode Listen Later Oct 20, 2021 110:50


O convidado é paleontólogo, professor na Universidade Nova de Lisboa, onde ensina, entre outras, evolução, paleontologia de vertebrados e répteis e -- a sua principal área de investigação -- dinossauros, sobretudo do Jurássico de Portugal. É autor ou co-autor de mais 200 publicações nesta área e já há três décadas que  participa e organiza escavações de dinossauros em Portugal, sobretudo em colaboração com o Museu da Lourinhã, conhecido por sua importante colecção de dinossauros.  -> Apoie este projecto e faça parte da comunidade de mecenas do 45 Graus em: 45graus.parafuso.net/apoiar Octávio Mateus é conhecido do grande público sobretudo enquanto especialista em dinossauros. Porque essa é, de facto, a sua principal área de investigação, mas também porque o imaginário destes répteis que dominaram a Terra até há 66 milhões de anos é, por motivos vários, o que mais atrai a atenção das pessoas. Mas a área do convidado, a Paleontologia, é muito mais do que simplesmente dinossauros. É uma área da ciência que vai beber simultaneamente à Biologia e à Geologia para tentar explicar a História da vida na Terra nos últimos (pelo menos) 3.5 mil milhões de anos, e nas suas mais variadas formas. Esta foi, como vão perceber, uma conversa cheia (o Octávio é um excelente conversador), na qual abordámos imensos temas. Falámos sobre a História da vida na Terra, desde os primeiros organismos unicelulares até aos dinossauros, aos mamíferos e ao homo sapiens. Falámos do processo da evolução por selecção natural, e do modo como ele é muitas vezes contra-intuitivo (um tema que já tinha abordado nos dois episódios que gravei com o PGM). Falámos também de fósseis, que são a matéria-prima principal de um paleontólogo.  E, claro, falámos (muito) sobre dinossauros: quantos eram, o que sabemos sobre eles, o que não sabemos, e ainda...o que é que os pássaros nos podem dizer sobre eles. Porque a verdade é que os pássaros descendem directamente dos dinossauros. Aliás, formalmente, os pássaros são um tipo de dinossauro, pois descendem (são, aliás, os únicos descendentes) do grupo ao qual pertencia nada mais nada menos do que o famoso tiranossauro rex. _______________ Índice da conversa: (02:57) O que é a Paleontologia? (05:46) É possível ressuscitar espécies extintas? | Lobo-da-tasmânia (08:49) O que é um fóssil? | Fósseis de tecidos moles. | Quais as condições ideiais para a fossilização? | Como se faz a datação de um fóssil? | Qual é o fóssil mais antigo? (25:51) Macro-história da evolução da vida na Terra | 890-million-year-old sponge fossil may be the earliest animal yet found | Explosão do Câmbrico. | Corrida ao armamento evolutiva (49:19) Quando surgiram os dinossauros? | Conseguimos saber quantas espécies havia? | Os mamíferos | Evolução da biodiversidade na Terra ao longo do tempo. | Os vários eventos de extinção. | paleontologia.pt (55:02) As três grandes famílias de dinossauros. | Debate em torno de paper recente saído na Nature (57:43) Porque é que os dinossauros (e os pássaros) desenvolveram sacos de ar no interior do organismo? (1:01:57) O modo como o passado evolutivo de uma espécie restringe as adaptações que pode desenvolver. | O exemplo do nervo vago | O exemplo das hemorroidas.  (1:06:49) Como era possível os saurópodes serem tão grandes? Comparação com os cavalos. “Corrida ao armamento evolutiva” | Lei de Cope | Porque foram os maiores dinossauros aqueles que se extinguiram?  (1:14:55) As peculiaridades das espécies nas ilhas. Elefantes anões (extintos) (1:17:03) Aves vs (outros) dinossauros: os dinossauros tinham penas | Exaptações | Escamas.   (1:20:36) Porque é que a taxonomia de Lineu deixa de fazer sentido numa visão global da história da evolutiva da Terra (1:23:34) O que nos dizem as aves (e os répteis) sobre como eram os dinossauros? | Phylogenetic bracketing | Como no filme Jurassic Park foi feito o rugido do T-rex  (1:26:19) O que sabemos sobre como eram os dinossauros (fisionomia, comportamento, etc)? | Os dinossauros eram de sangue quente ou frio? Qual é a vantagem do sangue quente? Porque evoluiu? (1:32:24) A principal interrogação do convidado sobre os dinossauros. | Quanto tempo dura cada espécie? | Known unknowns vs unknown unknowns  (1:37:15) O que causou a extinção dos dinossauros (Cretaceous–Paleogene extinction event) |  (1:43:30) Há esperança de encontrar DNA de dinossauros? | Possível descoberta de DNA de t-rex | Record de DNA (completo) mais antigo (mamute) (1:46:24) Livro recomendado: A Ascensão e Queda dos Dinossauros, de Steve Brusatte _______________ Obrigado aos mecenas do podcast: Julie Piccini, Ana Raquel Guimarães Miguel van Uden, José LuÍs Malaquias, João Ribeiro, Francisco Hermenegildo, Nuno e Ana, Nuno Costa, Galaró family, Salvador Cunha, João Baltazar, Miguel Marques, Corto Lemos, Carlos Martins, Tiago Leite Luis, Maria Pimentel, Rui Amorim, RB, Pedro Frois Costa, Gabriel Sousa, Mário Lourenço, Arune Bhuralal, Isabel Oliveira, Ana Teresa Mota, Filipe Bento Caires, Luí­s Costa, Manuel Martins, Diogo Sampaio Viana, Francisco Fonseca, João Nelas, Tiago Queiroz, Ricardo Duarte, António Padilha, Rita Mateus, Daniel Correia, João Saro, Tomás Costa Rui Baldaia, Joana Margarida Alves Martins, Luis Marques, Hugo Correia, Duarte , Francisco Vasconcelos, Telmo , Jose Pedroso, MANNA Porto, José Proença, Carlos Manuel Lopes de Magalhães Lima, Maria Francisca Couto, joana Antunes, Nelson Poças, Francisco López Bermúdez, Carlos Silveira, Diogo Rombo, Bruno Lamas, Fábio Mota, Vítor Araújo, João Pereira, Francisco Valente, Nuno Balsas, Jorge Amorim, Rui Vilão, João Ferreira, Luís Elias, José Losa, Hélder Moreira, Diogo Fonseca, Frederico Apolónia, André Abrantes, Henrique Vieira, João Farinha, Paulo Fernandes, Nuno Lages, João Diamantino, Vasco SÁ Pinto, Rui Carrilho, Luis Quelhas Valente, Tiago Pires, Mafalda Pratas, Renato Vasconcelos, João Raimundo, Francisco Arantes, Francisco dos Santos, Mariana Barosa, Marta Baptista Coelho, João Castanheira, Pedro , rodrigo Brazão, Nuno Gonçalves, Pedro Rebelo, Tomás Félix, Vasco Lima, Joao Pinto, João Moreira, José Oliveira Pratas, João Diogo Silva, Marco Coelho, Joao Diogo, Francisco Aguiar , Tiago Costa da Rocha, João Crispim, Paulo dos Santos, Abílio Mateus, João Pinho , Andrea Grosso, Miguel Lamela, Margarida Gonçalves, Afonso Martins, João Barbosa, Luis Filipe, Renato Mendes, António Albuquerque, Francisco Santos, juu-san, Fernando Sousa, Pedro Correia, MacacoQuitado, Paulo Ferreira, Gabriela, Nuno Almeida, Francisco Manuel Reis, Daniel Almeida, Albino Ramos, Inês Patrão, Patrícia Esquível , Diogo Silva, Miguel Mendes, Luis Gomes, Ana Batista, Alberto Santos Silva, Cesar Correia, Susana Ladeiro, Gil Batista Marinho, Filipe Melo, Cheila Bhuralal, Bruno Machado, Miguel Palhas, isosamep, Robertt , Pedro F. Finisterra, Cristiano Tavares, Pedro Vieira, Jorge Soares, Maria Oliveira, Bruno Amorim Inácio, Nuno , Wedge, Pedro Brito, Manuel Botelho da Silva, Ricardo Leitão, Vítor Filipe, João Bastos, Natália Ribeiro, Bernardo Pimentel, Pedro Gaspar, Hugo Domingues _______________ Esta conversa foi editada por: Hugo Oliveira _______________ Bio: Nascido em 1975, é Professor Associado de Paleontologia na Universidade Nova de Lisboa (FCT). É licenciado em Biologia (Univ. de Évora) e Doutorado em Paleontologia pela Universidade Nova de Lisboa. O seu principal tema de interesse é a paleontologia de dinossauros (ossos, ovos e pegadas), sobretudo do Jurássico de Portugal, mas também aborda outros répteis (mosassauros, plesiossauros, crocodilos, tartarugas, etc.). É autor ou co-autor de mais 200 publicações (capítulos de livros, artigos científios e resumos de conferências). Desde 1991 que participa e organiza em escavações de dinossauros em Portugal, sobretudo em colaboração com o Museu da Lourinhã, conhecido por sua importante colecção de dinossauros. Em Angola descobriu o primeiro dinossauro desse país no âmbito do Projecto PaleoAngola. O seu interesse por dinossauros já o levou a realizar escavações a Estados Unidos, Brasil, Gronelândia, Laos, Tunísia, Moçambique, Mongólia, Marrocos e Angola. É Investigador Associado do AMNH - Museu Americano de História Natural (New York) e do Museu da Lourinhã.

Palaeo After Dark
Podcast 222 - Static Hiss

Palaeo After Dark

Play Episode Listen Later Oct 10, 2021 102:59


The gang discusses two papers that look at evolutionary changes in animal groups after the End Cretaceous Mass Extinction. The first paper looks at morphometric changes in shark teeth, and the second paper studies the evolutionary and biogeographic patterns of snakes. Meanwhile, Amanda “fixes” her audio, Curt goes biblical, and James is missing.   Up-Goer Five (Curt Edition): Our friends talk about things that lived through a real bad time when a huge rock hit the big round place where we all live. The first paper looks at large angry animals that move through water and have pointed things in their mouths and soft bits where things have hard bits. We usually just find the hard pointed bits from the mouth because the rest of the body falls to bits when they die. So this looks at how these old hard bits change from before and after the big rock hit. What they found was that changes happened within groups, where some groups were hit hard and others were not. But if you look at all of the big angry animals, it looks like very little changes. The hard bits are doing things that look the same before and after the rock hit, but its different groups doing that. The second paper looks at animals with no legs and looked at changes in where they live and how quickly they change over time. The paper finds that after the big rock hit, one group was able to move to a new place. This move seems to happen when they also start making more of themselves. It seems that, for this big group of animals with no legs, the big rock hitting may have helped this group. It seems like a new place opened up after the big rock and the group took over and did well. There are also changes that we see when it gets colder in the time way after the rock hit.   References: Klein, Catherine G., et al. "Evolution and dispersal of snakes across the Cretaceous-Paleogene mass extinction." Nature Communications 12.1 (2021): 1-9. Bazzi, Mohamad, et al. "Tooth morphology elucidates shark evolution across the end-Cretaceous mass extinction." PLoS biology 19.8 (2021): e3001108.

Strange Animals Podcast
Episode 240: The End of the Dinosaurs

Strange Animals Podcast

Play Episode Listen Later Sep 6, 2021 24:51


Sign up for our mailing list! We also have t-shirts and mugs with our logo! Here we go. It's the big one, the Cretaceous-Paleogene extinction event! Further reading: How Birds Survived the Asteroid Impact That Wiped Out the Dinosaurs How an asteroid ended the age of dinosaurs Extinction event that wiped out dinosaurs cleared way for frogs How life blossomed after the dinosaurs died 66-million-year-old deathbed linked to dinosaur-killing meteor Show transcript: Welcome to Strange Animals Podcast. I'm your host, Kate Shaw. Here it is, the extinction event episode that everyone's been waiting for, or at least that everyone knows about. It's the one that killed off the dinosaurs and ushered in the age of mammals. It's probably the one we know most about and it's certainly the one we have the most paintings of, usually of a T. rex staring into the sky at an approaching comet. In episode 227 we talked about the end-Permian extinction event, which took place about 250 million years ago. The Cretaceous-Paleogene extinction event, or end-Cretaceous, took place just over 66 million years ago, which means that for almost 200 million years there was more or less smooth sailing in the world. Dinosaurs evolved during that time, and I think we can all agree that dinosaurs are fascinating animals. The largest terrestrial animals ever to live were dinosaurs, specifically the sauropods. Sauropods were just unimaginably huge. They were like walking buildings that ate plants, and even that doesn't give a good idea of their size. Some sauropods had extremely long tails as well as very long necks, which increased their length. Right now the largest sauropod known was probably Argentinosaurus that might have grown as long as 118 feet, or 36 meters, but paleontologists keep finding bigger and bigger sauropods. Some sauropods had extremely long necks that they held up like a giraffe. The tallest was probably Barosaurus, estimated as being 72 feet tall, or 22 meters. And we won't even get into estimates of how much these massive animals weighed. They make the biggest elephant that ever lived look like a toy elephant. Sauropods ate plants, with the low-necked species eating low-growing plants and the high-necked species eating tree leaves, although even saying that much is controversial. There's a lot we don't know about sauropods in general, since most sauropod fossils are incomplete and many species are only known from one or a few bones. But we do know some surprising things about sauropods. We have a lot of sauropod tracks, which helps us understand how their feet looked and whether they had claws, but it also tells us that some species of sauropod traveled in herds. Paleontologists do generally agree that many sauropods migrated, since animals that big would soon exhaust all the food in one area if they didn't. Sauropods were extremely successful and lived all over the world. There were plenty of sauropods alive 66 ½ million years ago, and then…there were no sauropods alive ever again. These days, there's so much evidence that a massive asteroid killed off the dinosaurs that pretty much everyone agrees, but when the idea was first proposed in 1980, it was extremely controversial. When I was a kid I remember reading dinosaur books that still said the extinction of the dinosaurs was a mystery but that many scientists thought it was due to disease or volcanoes. The asteroid strike hypothesis was proposed by the physicist Luis Alvarez and his son, Walter. They worked with a small team of other scientists, including two chemists, Helen Michel and Frank Asaro, to investigate a strange anomaly in rock strata. Rocks dating to the end of the Cretaceous period and the beginning of the Paleogene period are separated by a thin layer of clay that's visible throughout the world, or at least wherever the rocks remain and can be examined. It's called the Cretaceous-Paleogene boundary, or K-Pg boundary,

Race and Tyler Talk Wikipedia
40: Dinosaurs (Chicxulub Crater Part 2)

Race and Tyler Talk Wikipedia

Play Episode Listen Later Aug 17, 2021 54:16


We talk about the Cretaceous-Paleogene extinction, and the most famous victims of the Chicxulub Crater: the dinosaurs.

dinosaurs cretaceous paleogene chicxulub crater
Ephemeral Rift Podcast
ERP #11 - Paradoxes; Questions for Our First Guest

Ephemeral Rift Podcast

Play Episode Listen Later Jun 1, 2021 92:49


Intro: questions for our first guest Leftovers: human evolution and the Cretaceous-Paleogene extinction event article: https://ephemeralrift.com/the-cretaceous-paleogene-extinction-event-meteor-a-blessing-or-a-curse/ Appetizers: comparing more vs less, myers briggs personality types and tests, marxism communism capitalism and community Main Course: introduction to paradoxes (crocodile paradox, what the tortoise said to achilles, ant on a rubber rope, low birth weight paradox, the two envelope paradox, buradin's ass, hedgehog's dilemma, the paradox of tolerance, the paradox of the grain of millet, paradox of the plankton Dessert: M.C. Escher's optical illusions

Merriam-Webster's Word of the Day

Merriam-Webster's Word of the Day for December 6, 2020 is: mangle • MANG-gul • verb 1 : to injure with deep disfiguring wounds by cutting, tearing, or crushing 2 : to spoil, injure, or make incoherent especially through ineptitude Examples: "Named for the two geologic periods on either side of the event, the Cretaceous-Paleogene mass extinction happened with remarkable speed. Intense cold, constant darkness, wildfires, tsunamis, unbearable heat in the impact area, and eventual acid rain mangled the planet." — Michael Greshko, National Geographic, 29 June 2020 "What do we even know about Dua Lipa—or Dula Peep, as many of her fans call her (after Wendy Williams famously mangled the singer's name on her talk show)?" — Mikael Wood, The Los Angeles Times, 28 Aug. 2020 Did you know? Besides the "mutilate" verb mangle, English has the noun mangle ("a machine for ironing laundry by passing it between heated rollers") and its related verb ("to press or smooth with a mangle"). There's no etymological relationship, however, between that pair and the mangle that means "to mutilate or bungle." The ironing-related homographs come from Dutch and ultimately from a Latin word that also gave English mangonel, the name for a military engine used to hurl missiles. The injury-related mangle comes from Anglo-French and may be a relation of the words maim and mayhem via Anglo-French mahaigner, "to maim."

Fossil Huntress — Palaeo Sommelier

Ammonites / Ammonoids — Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids — octopus, squid, and cuttlefish — than they are to shelled nautiloids such as the living Nautilus species. The earliest ammonites appear during the Devonian, and the last species vanished in the Cretaceous–Paleogene extinction event. If you fancy a read or would like to see some photos of ammonites, check out the Fossil Huntress Blog ARCHEA at https://fossilhuntress.blogspot.com/ or visit the Fossil Huntress page on Facebook.

nautilus ammonites devonian cretaceous paleogene
Science Talk TV - (Education, News, Interviews)
Dinosaur extinction 101 | K-pg extinction event

Science Talk TV - (Education, News, Interviews)

Play Episode Listen Later Aug 13, 2020 12:52


Today, we learn about the extinction of the dinosaurs. How did volcanoes, an asteroid, climate change, and tectonic plates cause these once great creatures to disappear from the face of the earth? I also explain how the birds and our mamallian ancestors survive this extinction event, called the Cretaceous-Paleogene extinction (K-Pg for short). The dinosaur extincton happened about 66 million years ago and killed 70% of all species. Enjoy 3D animations and HD videos while listening to the English narration. Welcome to Dinosaur Extinction 101! Support me by using my Amazon (USA) link. I will get a small commission and the price is the same for you: https://sciencetalktv.com/best-and-cool-gifts-for-science-lovers/ Follow me on social media and support me on Patreon for video requests: https://www.patreon.com/ScienceTalkTV https://www.sciencetalktv.com https://www.facebook.com/ScienceTalkTV/ https://www.twitter.com/ScienceTalkTV1 https://www.youtube.com/ScienceTalkTV https://www.soundcloud.com/science-talk-tv timestamps: 0:00 - Dinosaur extinction introduction 0:36 - Dinosaurs dominate the Earth 1:11 - Volcanic global cooling (Deccan Traps) 3:05 - Chicxulub impact event 3:50 - A catastrophic impact 5:07 - Global food shortage 5:41 - Cretaceous-Paleogene boundary (K-Pg) 6:37 - Excavation and geology 7:04 - Plate tectonics and seal levels 8:21 - Quickly changing marine conditions 8:53 - The Great Dying 9:25 - The Theropods 10:16 - Natural selection (survival of the fittest) 10:51 - Our mamallian ancestors 11:43 - The Rise of the mammals 12:05 - Holocene extinction (ongoing) 12:24 - Support Science Talk TV General Credits: Videos: Property of Science Talk TV or StoryBlocks Standard License Animations: Science Talk TV Music: Youtube Audio Library Creative Commons Photos: Pixabay, wikimedia commons, and Canva Sound Effects: https://www.zapsplat.com Creative commons photo credits: https://commons.wikimedia.org/wiki/File:Mesosaurus_BW.jpg https://www.nps.gov/articles/plesiosaur-bone-fossil.htm https://commons.wikimedia.org/wiki/File:Plesiosaurus_3DB.jpg https://commons.wikimedia.org/wiki/File:Plesiosaur_model.jpg https://commons.wikimedia.org/wiki/File:Mesosaurus_JWArtwork.png https://commons.wikimedia.org/wiki/File:Pterodactyl_(PSF).png https://commons.wikimedia.org/wiki/File:Pterodactyl_fossil_reconstitution.jpg https://commons.wikimedia.org/wiki/File:LA-Triceratops_mount-2.jpg https://www.publicdomainpictures.net/pictures/300000/velka/triceratops-3d-drawing.jpg https://commons.wikimedia.org/wiki/File:Deccan_Traps_volcano.jpg https://vi.wikipedia.org/wiki/Tập_tin:Deccan_Traps_Matheran.jpg https://commons.wikimedia.org/wiki/File:Iridium-2.jpg https://commons.wikimedia.org/wiki/File:Pieces_of_pure_iridium,_1_gram._Original_size_-_0.1_-_0.3_cm_each..jpg https://www.flickr.com/photos/jsjgeology/15692057568 https://commons.wikimedia.org/wiki/File:IridiumLayerKTBoundaryRatonNM.png https://commons.wikimedia.org/wiki/File:Late_Cretaceous_metatherian_locales_-_ZooKeys_465.jpg https://vi.m.wikipedia.org/wiki/Tập_tin:Kansas_sea2DB.jpg https://commons.wikimedia.org/wiki/File:Ocher_fauna_DB.jpg https://commons.wikimedia.org/wiki/File:Diorama_of_a_Permian_forest_floor_-_Dimetrodon_2_(44977912954).jpg https://commons.wikimedia.org/wiki/File:Permian_amphibians.jpg https://commons.wikimedia.org/wiki/File:Phylogenetic_tree_of_Theropods_respiratory_system_01.JPG https://en.wikipedia.org/wiki/File:Morganucodon.jpg https://commons.wikimedia.org/wiki/File:Mammaliaformes.png #ScienceTalkTV #ScienceNews #ScienceEducation

Highlights from The Pat Kenny Show
What Did Kill The Dinosaurs ?

Highlights from The Pat Kenny Show

Play Episode Listen Later Jul 3, 2020 7:13


New research shows surge in volcanic activity could not have caused Cretaceous/Paleogene extinction event. For more on this research we heard from Prof. Peter Allison, Imperial College London, Department of Earth Science & Engineering. Listen and subscribe to The Pat Kenny Show on Apple Podcasts, Google Podcasts and Spotify.      Download, listen and subscribe on the Newstalk App.    You can also listen to Newstalk live on newstalk.com or on Alexa, by adding the Newstalk skill and asking: 'Alexa, play Newstalk'.  

Palaeo After Dark
Podcast 159 - Rocks Fall Everyone Dies; The Cretaceous Mass Extinction

Palaeo After Dark

Play Episode Listen Later Mar 31, 2019 82:17


The gang discusses two papers about the Cretaceous mass extinction event (i.e. the time that the non-avian dinosaurs died). Specifically, they talk about the Deccan Traps, a widespread volcanic province that was active during the extinction event. The first paper studies the timing of the volcanic activity to determine if the onset of volcanism can be explained by the large bollide impact (Editors Note: Apologies to all igneous petrologists who will likely be yelling at our ignorance of hard rock geology). The second paper uses ecological niche modeling to see if dinosaurs were experiencing significant reduction in their geographic range before the extinction event. Also, James is in a “good” mood, so please enjoy as we bounce between topics like Sinclair oil, the French Revolution, “training” children, and experiences at paleo festivals. Its definitely one of those podcasts.   Up-Goer Five (Amanda Edition):  Today our friends talk about the time when the big angry animals with no hair and large teeth all died. One of the ideas is that a very big rock hit and killed everything. Another idea is that rock that acts like water came out of the ground and changed the air and that killed everything by making things too warm or too cold. Many people are starting to think the rock that acts like water that came out of the ground killed the big angry animals with no hair and large teeth, because it seems like they died more slowly that maybe they should have if a big rock hit the ground and killed everything. That would be very fast. But then maybe the big rock that hit the ground really did kill everything, because it turns out that the rock that acts like water that came out of the ground maybe didn't happen at the same time that the big angry animals with no hair and large teeth died. It might also be that big angry animals with no hair and large teeth were maybe around in more places and maybe there were more big angry animals with no hair and large teeth than we think because we only have rocks in some places from some times and that makes it look like the big angry animals with no hair and large teeth died slowly, but maybe they actually died fast.   References:  Sprain, Courtney J., et al. "The eruptive tempo of Deccan volcanism in relation to the Cretaceous-Paleogene boundary." Science 363.6429 (2019): 866-870.   Chiarenza, Alfio Alessandro, et al. "Ecological niche modelling does not support climatically-driven dinosaur diversity decline before the Cretaceous/Paleogene mass extinction." Nature communications 10 (2019). 

Strange Animals Podcast
Episode 066: TYRANNOSAURUS REX

Strange Animals Podcast

Play Episode Listen Later May 7, 2018 16:33


Thanks to Damian, who suggested T. rex as a topic! Let’s learn all about the T. rex and especially the most famous and controversial specimen ever found, Sue. A T. rex: Sue, also a T. rex: Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. Our topic this week is a suggestion from Damian, who wants to hear about the one, the only, the tyrant lizard king with massive everything except arms, Tyrannosaurus rex. Aw yeah You probably know a lot about T. rex without realizing it. It’s THE dinosaur, the one people think of first when you say dinosaur. But a lot of popular knowledge about the T. rex is actually out of date, so let’s find out what’s really going on with that big toothy theropod. First of all, T. rex did not live in the Jurassic period. It lived much later, in the late Cretaceous, around 66 million years ago. But I guess Late Cretaceous Park doesn’t have quite the same ring to it. It was one of the last non-avian dinosaurs, dying off in the Cretaceous-Paleogene extinction. It lived in what is now western North America, with close relatives in many other parts of the world. T. rex was a big animal, no doubt about it. The biggest individual we know of, called Sue, stood around 12 feet tall, or a little over 3 ½ meters at the hips. The weight of its massive head was balanced by its long tail. Nose to tail it was around 40 feet long, or about 12 meters. Plenty of other dinosaurs were bigger than T. rex, but T. rex was the biggest land predator we know of. While T. rex had long legs, its arms are famously teeny, only about three feet long, or one meter. That’s barely longer than an adult human’s arm. But recent research shows that the arms weren’t weak. The bones were strong and so were the muscles, although the arm had a limited range of motion and only two toes. Many researchers think T rex used its arms to hold onto struggling prey. Since all we have are fossils, we don’t really know what T. rex looked like beyond its bones and muscles, which we know about from study of muscle attachment sites on the bones. Some researchers think it probably had at least some feathers, since we have feather impressions from some of T rex’s close relations. Baby T rex might have had feathers and shed them as it grew up, or it might have had feathers its whole life. We have fossilized skin impressions from a specimen found in 2002 that show scales on the tail, neck, and hip, so many researchers suggest that T rex only had feathers on its head and back, possibly for decoration or protection from the elements. Closely related species show feather impressions over all of the body, so we know T rex’s cousins were feathered. We also know that T rex had large flat scales on its snout with patches of keratin in the middle, which probably contained sensory bundles. These same patches are present in crocodilians, which help crocs move their eggs and babies without harming them, and help them sense the temperature of their nests. In 2016, researchers discovered that T rex’s teeth contained enamel. This makes the teeth harder, but enamel has to stay damp. That means T rex probably had lips and its teeth wouldn’t have been visible except when the mouth was open. If that sounds weird, most reptiles have lips. Crocodilians don’t, so some of their teeth show when their mouths are closed, but they also live in the water so don’t have to worry about dry mouth. Just to be clear, reptile lips aren’t big kissy lips. They’re just skin that allows the teeth to be completely enclosed within the mouth when the jaws are closed, keeping the mouth from drying out. In 2005, paleontologist Mary Schweitzer found soft tissue in the femur, or thigh bone, of a 68 million year old T rex. The tissue contained blood vessels and a substance called medullary bone, which is only present in female birds right before they lay eggs. Medullary bone helps the bird’s body make shells for her eggs.

north america nose jurassic tyrannosaurus rex cretaceous kate shaw baby t crocodilians cretaceous paleogene mary schweitzer
Palaeo After Dark
Podcast 98 - When the Mammal Extinctions Are

Palaeo After Dark

Play Episode Listen Later Nov 27, 2016 83:54


In this episode, we eventually get to discussing patterns of extinction selectivity in mammals during two major extinctions (the end Cretaceous and the modern biodiversity crisis). Also, James discusses delicious ways to end the world, Curt details the Lord of the Footballs, and Amanda really would like to know WHEN we're going to start discussing the papers. References: Longrich, N. R., J. Scriberas, and M. A. Wills. "Severe extinction and rapid recovery of mammals across the Cretaceous‐Paleogene boundary, and the effects of rarity on patterns of extinction and recovery." Journal of evolutionary biology (2016). Lyons, S. Kathleen, et al. "The changing role of mammal life histories in Late Quaternary extinction vulnerability on continents and islands." Biology Letters 12.6 (2016): 20160342.

Fakultät für Geowissenschaften - Digitale Hochschulschriften der LMU
Magmatic dyke systems of the South Shetland Islands volcanic arc (West Antarctica): reflections of the geodynamic history

Fakultät für Geowissenschaften - Digitale Hochschulschriften der LMU

Play Episode Listen Later Jun 2, 2005


The Antarctic Peninsula forms part of a magmatic arc at least since Jurassic times. Magmatic dykes are essential elements of such arcs and intrude along zones of instability. In contrast to other hypabyssal intrusions and the effusive products of arc activity, dykes do not only reflect the geochemical characteristics of their magma source but also the tectonic parameters at the time of their emplacement. The South Shetland Islands form an archipelago located at the northern tip of the Antarctic Peninsula and belong to this arc. Areas of up to 100,000 m2 have been mapped at several locations of these islands, mainly on King George and Livingston Island. A structural analysis of the dykes and the host rocks was carried out, and about 250 dykes were sampled for further studies. As deduced from field relationships, on Livingston Island six different intrusive events could be distinguished, on King George Island up to seven. This subdivision into different intrusive events is also well reflected by the geochemical data. Analysis of the structural data of the dykes and their host rocks shows, that the tectonic stress field was not only very similar throughout the archipelago, but that moreover only minor changes of this stress field occurred during the time of dyke emplacement. This holds for all investigated areas in the South Shetland Islands. The geochemical data (ICP-MS) reveal, that most dykes of the South Shetland Islands belong to a calc-alkaline, arc-related suite, ranging from basalts to highly differentiated rhyolites. However, especially during early stages of intrusive activity in the respective areas, also tholeiites occur. Isotopic data (Sr, Nd, Pb) prove a strong crustal component during initial stages of magmatic activity, especially on Hurd Peninsula (Livingston Island). This crustal component decreased with time, accompanied by an increase of sedimentary input into the subduction zone. The high amount of crustal contamination during the initial stages was probably due to a still unstretched continental crust. Besides the continental crust underlying the South Shetland Islands, partial melts from the subducted sediments, fluids derived from the subducting plate and a depleted, heterogeneous mantle wedge contributed to arc magma genesis. According to Ar-Ar datings on plagioclase separates and K-Ar (WR) age determinations, dyke intrusion was restricted to the Paleocene and Eocene. The dykes started to intrude around the Cretaceous/Paleogene boundary at Livingston Island. Only around the Thanetian/Ypresian boundary, dyke intrusion commenced also further NE at Nelson and King George Island, culminating during the Lutetian at 47-45 Ma in all investigated areas. Dyke intrusion then ceased in the latter areas but still continued at Livingston Island until the Priabonian. Combining the information given by the tectonic and geochemical datasets, the time interval covered by the dykes obviously marks a period of geodynamic stability. This includes a stable geometry of the subduction zone and the corresponding parameters (subduction direction and velocity) during that time, as well as stable magma sources. The contribution of the respective sources (sediments, slab, mantle, crust) varied, but the sources themselves remained the same. Very primitive, olivine tholeiitic dykes sampled on Penguin Island as a by-product of this work yielded an unexpectedly high Ar-Ar age (Tortonian), thus questioning the onset of rifting in Bransfield Strait during the Pliocene, as believed so far.