The Science Of Why An Asteroid, Not A Comet, Wiped Out The Dinosaurs
“The most important thing is that we all learn what the correct scientific conclusion to draw is, and why. The impact event that occurred 66 million years ago was due to an asteroid, not a comet. We know this based on many reasons, including the very compelling chemical composition of the impactor, retrieved from Chicxulub crater and matched up with the layer of ash and clay found worldwide at the appropriate depth within sedimentary rock. A comet simply has the wrong properties, and the earlier study that claimed otherwise wasn’t just in error, but contained a series of unacceptably gross errors that should have resulted in the paper’s rejection.
The larger ethical issue, however, remains unresolved. What do we do about scientists who are so full of themselves that they willfully barge into a field they have no expertise in, and rather than work to gain that expertise and contribute meaningfully, they simply publish a superficial analysis to further their own fame and careers? This sort of practice must be discouraged, the same way we discourage those with no scientific expertise from contributing nonsense: through quality peer review. The alternative is to play an unwinnable game: scientific understanding by debate and public opinion. In the enterprise of science, it must always be facts and evidence, not persuaded minds, that carry the day.”
Did you read, back in February, that a comet, not an asteroid, wiped out the dinosaurs?
[ 07 - Undead ] Some recent “sightings” of Tasmanian tigers/Thylacines inspired this idea. The last of its kind died in a zoo in 1936. #art #artistsoninstagram #drawing #illustration #inktober #inktober2018 #micron #halloween #tasmaniantiger #thylacine #extinction #gore #animal #cocoxoart https://www.instagram.com/p/BoqKyyiAfCw/?utm_source=ig_tumblr_share&igshid=8pne3u0j87uc
The Last Animals is a story about an extraordinary group of people who go to incredible lengths to save the planet’s last animals. The documentary follows the conservationists, scientists and activists battling poachers and transnational trafficking syndicates to protect elephants and rhinos from extinction. From Africa’s frontlines to behind the scenes of Asian markets to the United States, the film takes an intense look at the global response to this slaughter and the desperate measures to genetically rescue the northern white rhinos who are on the edge of extinction.
Sudan is THE LAST male northern white rhino on our planet. One of his caregivers at Ol Pejeta Conservancy has some wise words from the majestic, soon to be extinct rhino in his care:
Sudan you are ok and healthy,though you spend many days alone,I wish you can tell the story more than i do; tell them how life was in southern Sudan, before that finger pulled the trigger and saw your brothers,…
Name:JamesAge:29Location:Ol Pejeta in Kenya I have been a ranger for the last 5 years now,3 years as a rhino patrol man and 2 years now as the last three northern white rhinos caretaker. I grew with a passion for the conservation of nature,I realised there was need to have a right-minded people who would speak out for poaching stricken elephants and rhinos, as well other living…
looking at photographs of now-extinct animals fucks me up supremely. like man… this thing must’ve died out less than 300 years ago for us to have pictures of it……… in the grand scheme of things, that’s incredibly recent. and when the last one remained, we couldn’t do anything about it, so we just did the best we could to document it. to make sure the people of the future knew about it, and could maybe prevent further extinctions…………. man……………………………..
WASHINGTON, DC — The scimitar-horned oryx has been resurrected from the dead. It’s been 30 years since the antelope was declared extinct, and now, thanks to the Smithsonian National Zoo, it’s headed back to the Sahelian grasslands of Chad where it once roamed.
AbstractThe late Quaternary megafauna extinction was a severe global-scale event. Two factors, climate change and modern humans, have received broad support as the primary drivers, but their absolute and relative importance remains controversial. …
We present, to our knowledge, the first global analysis of this extinction based on comprehensive country-level data on the geographical distribution of all large mammal species (more than or equal to 10 kg) that have gone globally or continentally extinct between the beginning of the Last Interglacial at 132 000 years BP and the late Holocene 1000 years BP, testing the relative roles played by glacial–interglacial climate change and humans.
We show that the severity of extinction is strongly tied to hominin palaeobiogeography, with at most a weak, Eurasia-specific link to climate change. …
IMAGE Global maps of late Quaternary [a, b] large mammal extinction severity, [c] hominin palaeobiogeography, [d] temperature anomaly and [e] precipitation velocity. [More detail here…]
Top Shot features the photo with the most votes from the previous day’s Daily Dozen, 12 photos selected by the Your Shot editors. The photo our community has voted as their favorite is showcased on the @natgeoyourshot Instagram account. Click here to vote for tomorrow’s Top Shot.
“All 5 species of rhinos are either critically endangered, vulnerable or threatened. When the world’s last male white rhino died, something of mankind died with it too,” writes Your Shot photographer Shobha Gopinath. “For years they have been hunted for the supposed medicinal value of their horn. When will man learn to share this planet with our fellow creatures? This image of the baby rhino with its mother [in Cape Town, South Africa] standing still in the midst of a swirling sandstorm seemed like a perfect metaphor of their vulnerability.” Photograph by Shobha Gopinath
KILLING THE PLANET AND ITS BEAUTIFUL LIFE FORMS. Vaquita, a small porpoise is the world’s most rare marine mammal, and is on the edge of extinction. … Vaquita are often caught and drowned in gillnets used by illegal fishing operations in marine protected areas within Mexico’s Gulf of California. The population has dropped drastically in the last few years.
Check out the UI Library’s Center for Digital Inquiry and Learning (CDIL) student-led digital humanities project: Storying Extinction.
This project highlights the recently extirpated mountain caribou of Idaho. The project, co-led by former English graduate students, Jack Kredell and Chris Lamb, under the guidance of CDIL Director, Devin Becker, is a multilayered, web-based ‘deep map’ that represents community response to the local extinction.
Time: 201.3 million years ago, in the Rhaetian age of the Late Triassic of the Mesozoic of the Phanerozoic
Analogy: Did you ever play on a team in High School? Even like an academic one? I was on my school’s Science Olympiad team (always won a medal in fossils, thank you very much. I also was in charge of organizing bio events, no big deal). Anyway do you remember when, like, the upperclassmen graduated, and suddenly you had a lot of responsibility and you were an important member of whatever club or team you were on? Like, they disappeared, and you got to take their place and be the big guys? Yeah that’s this, but for dinosaurs.
Causes: Where did we leave off? Oh right nearly everything died. My favorite! Well life eventually did recover after the Permian Extinction - obviously, as we’re all here today. Archosauromorphs were really taking over the scene, and there we many different kinds everywhere - dinosaurs were a relative minority compared to all the other different types of reptiles, and pterosaurs were extremelyrare as well. Nothosaurs, Pachypleurosaurs, Placodonts, and the first Plesiosaurs evolved; there were Thalattosaurs, and Ichthyosaurs were verysuccessful in the Triassic. There were many amphibians, Rhynchosaurs, Phytosaurs, Aetosaurs, Rauisuchians, the first Crocodylians, Prolacertiformes, the earliest turtles, and the cynodonts all evolved and diversified, with cynodonts getting closer to being mammals. In fact, looking at the assemblage of the Triassic, one could hardly guess that it would be dinosaurs that would become the dominant megafauna of the Mesozoic period - various Pseudosuchians (crocodile-line Archosaurs) seemed to be taking that role.
So what happened then? After all, this is pretty quick after the last death machine - only about fifty million years. Well, the causes of this extinction are actually… not very clear. Once again people have tried to pin it on an asteroid - which would make somesense, since it was the large non-dinosaurian archosaurs that were hit the hardest - but no such crater has been found, and all possible candidates have been ruled out. There was some climate change and sea level fluctuations, but they weren’t sudden enough to explain the extinctions in the ocean - this was a very sudden pulse of death, more so than what you would expect from just gradual environmental fluctuations.
Theremayhave been some massive volcanic eruptions again - yay! more lava! - which seems to be the best bet. The flood basalts of the Central Atlantic Magmatic Province would have released carbon dioxide, sulfur dioxide, and aerosols, causing - once again - pretty terrible global warming and cooling. There seems to be evidence for a major CO2 greenhouse crisis in ocean extinction deposits, and evidence that both the marine and terrestrial extinctions happened at once, which may indicate that a sudden influx of carbon dioxide and accompanying warming caused the extinction. However, there’s a chance that the eruption of the CAMP was too old to have caused the extinction.
If it was the volcanic activity, perhaps exacerbated by already occurring climate change, then the increase in global temperatures would have had another terrible effect on life on the planet - which had just recovered, and thus would be fairly vulnerable.
Extinction Rate: This was not as bad of an extinction pulse as the last one, so if it was volcanic activity, it was the kind notin the worst possible place ever. Hooray! 23% of all families, 48% of all genera, and 70 to 75% of all species went extinct.
Effects: This was actually more acutely felt in the terrestrial environments than in the marine ones, though they were also affected. A large portion of the non-dinosaurian Archosauromorph groups went extinct, which emptied ecological niches on the land extensively. In the ocean, there seemed to just be less diversification - a decrease in speciation events rather than an extinction of already existing taxa. Phytosaurs and Aetosaurs were completely wiped out, as well as others.
If we can call any time periods much of anything, then, the Triassic was truly the age of reptiles, with a wide variety of forms and diversity across different major clades. One could argue, then that this age ended after the Triassic extinction - though many reptiles remained very common, it was really more specifically the Age of Dinosaurs after this point. Dinosaurs evolved to fill the vacant niches and finally started growing to the sizes to which we are accustomed with them - sauropods started evolving (at last, from stinking prosauropods), large theropods began to grow more and more common, and Ornithischians also finally had a chance to diverge.
In fact, the rapid pulse of diversification of dinosaurs after the end-Triassic extinction lead to a large morphological diversity of dinosaurs, and at some point between the middle and late Jurassic epochs, the earliest members of Avialae evolved - the group that would eventually lead to birds.
Mammals also evolved in the Early Jurassic, probably due to pressures following this extinction event. They remained small predators, living in regions where there was still many places to hide, though they did diversify somewhat, and more so than previous paleontologists believed.
So, though a relatively minor extinction, it once again directly lead to the world we know and love today - mammals became a thing, dinosaurs grew into what we really know and love about them (widely diverse and weird, because birds are weird you guys,) and other reptiles began to dominate the sea and air (hellooooo pterosaurs, pterosaurs everywhere). In fact, dinosaurs were so versatile and widely morphologically diverse following the Triassic extinction, thanks to all those sweet, sweet available niches, that they were very well adapted to their world.
![[ 07 - Undead ] Some recent “sightings” of Tasmanian tigers/Thylacines inspired this idea. The last](https://64.media.tumblr.com/498e8ae736e2179f79e1371adf6e5abb/tumblr_pg9jemoG121tii0zpo1_1280.jpg "[ 07 - Undead ] Some recent “sightings” of Tasmanian tigers/Thylacines inspired this idea. The last")
Sudan is THE LAST male northern white rhino on our planet. One of his caregivers at Ol Pejeta Conservancy has some wise words from the majestic, soon to be extinct rhino in his care:
![mucholderthen: Global late Quaternary [132,000 to 1,000 years ago] Megafauna Extinctions linked to](https://64.media.tumblr.com/104acfb5a9a09f60a9a4e69dfbe911da/tumblr_n8s612mmnq1rhb9f5o2_r1_1280.jpg "mucholderthen: Global late Quaternary [132,000 to 1,000 years ago] Megafauna Extinctions linked to")
