#The Permian-Triassic Extinction Event

[immoren]

These youtube challenges are getting out of hand

[bestanimal]

Round 2 - Mollusca - Bivalvia

(Sources - 1, 2, 3, 4)

Bivalvia is a class of molluscs whose bodies are enclosed by a pair of half-shells called valves, though some bivalves, like the Naked Clam (Chlamydoconcha orcutti) (image 2) have secondarily lost their shells. Bivalves have no head and no radula. Their gills have evolved into ctenidia, specialised organs for feeding and breathing. Bivalvia includes the clades Heteroconchia, Palaeoheterodonta, Protobranchia, Pteriomorphia, and animals commonly known as clams, oysters, cockles, mussels, and scallops.

Bivalves live in marine and freshwater environments. Most are filter feeders that bury themselves in sediment, lie on their side on the seafloor, or attach themselves to rocks or other hard surfaces. Some bivalves, such as scallops and file shells, can swim (see gif below). Shipworms bore into wood, clay, or stone and live inside these substances. Bivalve shells are composed of two calcareous valves joined along one edge by a flexible ligament that, usually in conjunction with interlocking "teeth" on each of the valves, forms the hinge, allowing the animal to open and close its shell. The animal secrets its shell from lobes on its mantle. They have a foot located at the front of their shell and two siphons in the back, which inhale and expell water. The shipworms, of the family Teredinidae, have elongated bodies but tiny, reduced shell valves, which function as scraping organs that permit the animal to dig tunnels through wood. Bivalves have sensory organs located on the margins of their mantle, usually mechanoreceptors or chemoreceptors, sometimes on short tentacles. All bivalves have light-sensitive cells that can detect a shadow falling over the animal, some have simple eyes on the margin of the mantle, and scallops have complex eyes with a lens, a two-layered retina, and a concave mirror. Most bivalves are filter feeders, using their gills to capture particles of food such as phytoplankton from the water. Protobranchs feed in a different way, scraping detritus from the seabed with mucus-covered tentacles. A few bivalves, such as the Granular Poromya (Poromya granulata), are carnivorous, eating larger prey like small crustaceans, though they will also scavenge. It does this though its inhalant siphon which is modified into a cowl-shaped organ, sucking in prey, and then inverting to bring the prey within reach of the mouth.

Most bivalves have separate sexes, though some are hermaphroditic. Fertilization is external in most species. Spawning may take place continually or be triggered by environmental factors such as day length, water temperature, or the presence of sperm in the water. Eggs hatch into free-swimming, planktonic trochophore larvae. These later develop into veliger larvae which settle on the seabed and undergo metamorphosis into adults. In some species, such as those in the genus Lasaea, females draw sperm in through their inhalant siphons and fertilize their eggs inside their bodies. These species then brood the young inside their mantle cavity, eventually releasing them into the water column as veliger or glochidia larvae or as crawl-away juveniles. The juveniles of freshwater bivalves will attach themselves parasitically to the gills or fins of a fish host. After several weeks they drop off their host, undergo metamorphosis and develop into adults on the substrate.

Bivalves first appear in the fossil record in the Early Cambrian. Possible early bivalves include Pojetaia and Fordilla, though these are probably stem-bivalves. True Cambrian bivalves may include Camya, Arhouriella, and Buluniella. Bivalves began to diversify during the Early Ordovician. By the Early Silurian, gills were adapting for filter-feeding, and during the Devonian and Carboniferous periods, siphons first appeared along with the newly developed muscular foot. At this point Brachiopods were still the most dominant filter-feeders in the ocean, but the Permian–Triassic extinction event hit both brachiopods and bivalves hard, but resulted in bivalves becoming the more common filter-feeders by the Triassic Period.

(source)

Propaganda under the cut:

Bivalves have long been a part of the diet of coastal and riparian human populations. Oysters were cultured in ponds by the Romans, and mariculture has more recently become an important source of bivalves for food.

Pearl Oysters (the common name of two very different saltwater and freshwater families) are the most common source of natural pearls.

Some of the species in the freshwater mussel family Unionidae (commonly known as Pocketbook Mussels) have evolved an unusual reproductive strategy. The female's mantle protrudes from the shell and develops into an imitation small fish, complete with fish-like markings and false eyes. This decoy moves in the current and attracts the attention of real fish. When fish approach for a closer look the mussel releases huge numbers of larvae from its gills, dousing the inquisitive fish with its tiny, parasitic young. These glochidia larvae are drawn into the fish's gills, where they attach and trigger a tissue response that forms a small cyst around each larva. The larvae feed on the tissue of the fish within the cysts. After a few weeks they release themselves from the cysts and fall to the stream bed as juvenile molluscs.

One genus, Entovalva, are parasitic as adults, being found only in the esophagus of sea cucumbers. They attach themselves via byssal threads to the host's throat, filter-feeding from the sediment sucked in by the sea cucumber. (This does not hurt the sea cucumber.)

The largest bivalve is the Giant Clam (Tridacna gigas) which can weigh over 200 kilograms (440 lb), measure as much as 120 cm (3.11 ft) across, and have an average lifespan in the wild of more than 100 years.

The shells of bivalves are used in craftwork, and the manufacture of jewellery and buttons.

As filter-feeders, bivalves are natural water filters. A single 5.08 cm (2 inch) clam can filter up to 10-12 gallons of seawater a day. They can even filter microplastics out of polluted water.

When they live in polluted waters, bivalves have a tendency to accumulate substances such as heavy metals and persistent organic pollutants in their tissues. This is because they ingest the chemicals as they feed but their enzyme systems are not capable of metabolising them and as a result, the levels build up. This may be a health hazard for the molluscs themselves, and is one for humans who eat them. It also has advantages in that bivalves can be used in monitoring the presence and quantity of pollutants in their environment.

The farming of bivalves is more ecologically-friendly than the farming of chordates as, rather than create waste, bivalves like mussels and oysters actually clean the water.

Scallops have beautiful eyes:

(source)

[timefadesaway]

david tennant survived the great tumblr sexyman extinction event like cynodonts through the permian-triassic extinction

[mist-fire]

"The Doctor's companion should be a history major!"

Yes. But have you also considered: ✨geologist✨

Imagine the Doctor befriends some random person, they get along pretty well, but through some events or another, they realize/get taken on a trip in the TARDIS, and they're just staring at the Doctor, eyes absolutely fucking huge. Their voice is desperate and disbelieving when they say, shaking a bit:

"You can travel in time?"

The Doctor is bemused and just goes, "yes?"

Their eyes get even wider if possible, and then they ask: "Can we go to the Permian?"

Once again, the Doctor's a bit baffled, but hey, who cares, might as well take a trip a few hundred million years into the past. The person gives them specific coordinates, which is also a bit weird, but makes it easier to navigate, so who are they to complain.

The Doctor flings open the doors, and the person just looks outside at the massive incised valley on the coastline and just starts sobbing. They're a PhD student. Their entire thesis is about the fluctuations in sea level during the Permian, and the mass extinction at the Permi-Triassic boundary.

They've just been proven right.

And hey, the Doctor likes the geologist well enough, and likes them even more after they start asking intensely theoretical questions about the deep past and future, so they take them as a companion. They visit the Grand Canyon to discover that, yes, the Western side is only 6 million years old. They jump to the future to watch plate tectonics.

When they go to other planets, the geologist is of course curious about the culture, but even more curious about the geochemistry of the planet, and how was that mountain formed over there, and do they have plate tectonics, is the geomorphology the same if the gravity differs on each planet? And the Doctor is thrilled because look, someone new to info dump on, and they seem to be understanding almost everything they're saying about the composition of the crust, and the different types of rocks on each planet.

Like, you can't tell me they each wouldn't love that. I would love that, so.

[a-dinosaur-a-day]

Quaternary includes both the Pleistocene and Holocene extinction pulses, even though the first may not be entirely anthropogenic

I’m not including the great oxygenation event because that is the least clear in terms of whether or not it actually was an extinction

[mineralsrocksandfossiltalks]

Fossil Friday : Lystrosaurus

Talk about a face only a mother could love. Lystrosaurus may not be the prettiest animal but it is an incredibly important one. Discovered in 1870 by Dr. Elias Root Beadle, he tried to reach out to Othniel Charles Marsh who unfortunately never responded. So, Beadle reached out to Edward Drinker Cope who described and named the animal.

Lystrosaurus is a dicynodont therapsid, a group of non-mammalian therapsids. It wasn't very big, averaging about 3 ft in length. Like other dicynodonts, it had a very short snout that may have ended in a hory beak. It had only two tusk-like teeth at the front of the mouth. It had weak jaw joint and moved backward and forward in a shearing motion rather than up and down.

It moved with a semi-sprawling gait and it's massive forelimbs suggest it was a powerful burrower.

In 2022, a mummified Lystrosaurus was found in the Karoo Basin in Africa. It showed dimpled, leathery, hairless skin.

The most incredible thing about these animals is when and where they lived. It lived from the Late Permian through the Early Triassic. That means it survived the Great Dying, the biggest extinction event the Earth has seen.

How did it do this? We're not sure but there have been a few ideas put out:

it was really god at hibernating

it could burrow and avoid the worst of the extinction event

it was semi-aquatic

it was not specialized for certain foods

shortage of predators

he got lucky

As you can see, lots of ideas have been thrown around but nothing concrete yet has been found. We're still not entirely sure what caused the extinction either which makes things difficult.

The other big deal about this animal is where its fossils have been found.

Currently, these countries are pretty far apart but if we put them together:

We can see that it makes sense why we find Lystrosaurus where we do.

Tune in Monday for an in depth look at the Ring of Fire! Have a good weekend and fossilize you later!

[mesozoicmarket]

A trilobite fossil of a Paladin mucronatus rotundatus from the Four Fathom Limestone Member, Alston Formation in Ireshopeburn, County Durham, England. Carboniferous to Permian aged proetids like Paladin were one of the last trilobites after the Late Devonian Extinction which decimated all other clades. Possibly due to this massive loss in diversity, trilobites would later go extinct during the Permian–Triassic Extinction Event or Great Dying.

[maklodes]

The first "big event" I can think of that makes me think "that really sucked. It's bad that that happened" is the Permian-Triassic Extinction Event, wiping out most of Earth's life 252 million years ago. The first "big event" I can think of that makes me think "that was cool. It's a good thing that that happened" is the Reforms of Solon, establishing a more-or-less democratic Athens 2617 years ago.

Feels a little asymmetrical.

[miscellaneoussmp]

Quick addition to my paleontology analysis because I'm a nerd and I need to get across how fucking old Badboyhalo is!!!

Bad is at least as old as the Cretaceous-Paleogene (K-Pg/K-T) mass extinction! This is the extinction event that killed off all of the Non-Avian dinosaurs! In total, it killed about 60 to 70% of all species on earth! This happened around 66 million years ago!

Bad is also possibly as old as the Permian-Triassic mass extinction, then he would have also been around for the Triassic-Jurassic mass extinction event. This extinction event killed off about 80% of all species on earth! It happened around 201.3 million years ago!

Bad might be as old as the Permian-Triassic mass extinction event! This extinction event killed off about 90% of all species on earth! It is the largest known mass extinction event! This happened around 251.9 million years ago!

That is at least one mass extinction event that Bad would have been around for!!!

[rainbow-femme]

Can’t stop thinking about mass extinction events. People generally know about the one that killed the dinosaurs but there have been 5 mass extinction events in earths history. The Permian-Triassic event had earth lose over 90% of species and it bounced back to then have the Triassic-Jurassic extinction event, and then it bounced back again, and then the Cretaceous extinction, and it bounced back to the way we are now

There have been so many different versions of earth. It’s easy to think of it as two phases, dinosaurs and then us, but there are multiple completely different worlds that have happened in the exact same spot and no matter how terrible an event occurs, if something is alive then the entire earth manages to still come back

[andy-paleoart]

The great dying: Permo-Triassic extinction | A grande morte: Extinção Permo-Triássica

🇬🇧

The Permian-Triassic Extinction is the most devastating mass extinction event in Earth's history, occurring approximately 252 million years ago, at the end of the Permian period and the beginning of the Triassic period. This mass extinction resulted in the loss of up to 96% of marine species and 70% of terrestrial species.

The exact causes of the Permian-Triassic Extinction are still debated among scientists, but several theories have been proposed. One of them is intense volcanic activity, such as the massive eruption of the Siberian Traps, a large volcanic province in Russia. This activity released huge amounts of greenhouse gases into the atmosphere, causing drastic climate change and ocean acidification.

These catastrophic events caused widespread mass extinctions, affecting both marine and terrestrial organisms. The recovery of biodiversity after the Permian-Triassic Extinction took millions of years and profoundly influenced the subsequent evolution of life on Earth.

The relationship between the Permian-Triassic Extinction and current climate events can be observed through similarities in causative factors and consequences for life on Earth. Similarly, contemporary climate events are largely influenced by human activities, particularly the burning of fossil fuels, which releases greenhouse gases into the atmosphere. This anthropogenic activity has led to global warming, changes in precipitation patterns, rising sea levels, and ocean acidification, among other impacts. These changes are putting immense pressure on ecosystems and biodiversity, leading to species extinctions and ecosystem degradation. Both the Permian-Triassic Extinction and current climate events highlight the profound impact that changes in climate can have on life on Earth. Understanding the parallels between these events can help inform efforts to mitigate the current climate crisis and protect the planet's biodiversity and ecosystems.

🇧🇷

A Extinção Permiano-Triássica é o evento de extinção em massa mais devastador da história da Terra, ocorrido há cerca de 252 milhões de anos, no final do período Permiano e início do período Triássico. Esta extinção em massa resultou na perda de até 96% das espécies marinhas e 70% das espécies terrestres.

As causas exatas da Extinção Permiano-Triássica ainda são objeto de debate entre os cientistas, mas várias teorias foram propostas. Uma delas é a atividade vulcânica intensa, como a erupção em massa dos Trapps Siberianos, uma grande província magmática na Rússia. Essa atividade liberou enormes quantidades de gases de efeito estufa na atmosfera, causando mudanças climáticas drásticas e acidificação dos oceanos.

Esses eventos catastróficos causaram extinções em massa generalizadas, afetando tanto organismos marinhos quanto terrestres. A recuperação da biodiversidade após a Extinção Permiano-Triássica levou milhões de anos e influenciou profundamente a evolução subsequente da vida na Terra.

A relação entre a Extinção Permiano-Triássica e os eventos climáticos atuais pode ser observada através de semelhanças nos fatores causadores e nas consequências para a vida na Terra. Da mesma forma, os eventos climáticos contemporâneos são amplamente influenciados por atividades humanas, particularmente a queima de combustíveis fósseis, que libera gases de efeito estufa na atmosfera. Essa atividade antropogênica tem causado o aquecimento global, mudanças nos padrões de precipitação, aumento do nível do mar e acidificação dos oceanos, entre outros impactos. Essas mudanças estão exercendo uma pressão imensa sobre os ecossistemas e a biodiversidade, levando a extinções de espécies e degradação dos ecossistemas. Tanto a Extinção Permiano-Triássica quanto os eventos climáticos atuais destacam o profundo impacto que as mudanças climáticas podem ter na vida na Terra. Compreender os paralelos entre esses eventos pode ajudar a informar esforços para mitigar a atual crise climática e proteger a biodiversidade e os ecossistemas do planeta.

[dougdimmadodo]

May’s Fossil of the Month - Thrinaxodon (Thrinaxodon liorhinus)

Family: Thrinaxodon Family (Thrinaxodontidae)

Time Period: Early Triassic (251-247 Million Years Ago) 

At the end of the Permian period around 251 million years ago, the earth experienced the most extreme extinction event in its history (known as the Permian-Triassic Extinction Event or “The Great Dying”,) in which some 70% of terrestrial species and 81% of marine species were driven to extinction. As such, the period immediately following the Permian, the early Triassic, was a period of slow recovery as the descendants of the few survivors of the Great Dying began to adapt and diversify to fill the ecological niches left empty by the extinction of their previous occupants. Thrinaxodon liorhinus was one such survivor; a small (roughly 50cm/1.6 feet in length) species of cynodont synapsid (making it a close relative of mammals, but not a mammal itself), it inhabited what is now southern Africa and northern Antarctica (which were fused as part of a single landmass at the time) in the period immediately following the great dying, and was seemingly among the largest and most common carnivores of its time. Thrinaxodon’s survival was likely enabled at least in part due to its lifestyle; the discovery of individuals fossilized in the remains of burrows show that Thrinaxodon, like many similarly-sized mammals today, was a burrower, and the presence of distinct divisions on its spine to aid in flexibility suggests that, like many burrowing mammals and reptiles today, it may have possessed the ability to travel deeper underground and undergo hibernation or aestivation in order to endure prolonged periods of harsh weather conditions and resource scarcity. In life Thrinaxodon would have likely appeared somewhere between a large lizard and a small dog, with its leg bones and joints suggesting that it stood in a “semi-sprawling” posture mid-way between the belly-to-the-ground sprawling of most lizards and the elevated posture of most mammals, while its dog-like skull and sharp-tipped teeth (including prominent canines on both the upper and lower jaw) suggest that it was likely carnivorous, feeding on insects and/or smaller vertebrates. The discovery of the remains of several Thrinaxodon individuals, sometimes including juveniles, preserved in close proximity to one another suggests that members of this species likely provided parental care and may have also been social, and one unusual but extremely famous fossil burrow containing both an adult Thrinaxodon and an injured Broomistega putterilli (a small species of superficially salamander-like amphibian) showing puncture wounds from teeth too large to belong to the burrow’s owner suggests that, like the Gopher Tortoise and Giant Armadillo today, Thrinaxodon may have been a habitat engineer, with its burrows providing shelter for other species of animal (although it is also possible that the Broomistega had been washed into the burrow during a flood that killed both animals, or that the Thrinaxodon had stolen the injured Broomistega from the larger carnivore that wounded it.)

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Image Sources:  https://commons.wikimedia.org/wiki/File:Thrinaxodon_liorhinus_BP_1_7199.jpg

and

https://www.pbs.org/video/the-oddest-couple-in-the-fossil-record-rcehau/

[bestanimal]

Round 1 - Phylum Brachiopoda

(Sources - 1, 2, 3, 4)

Brachiopoda is a phylum of animals that are superficially similar but entirely unrelated to bivalve molluscs, in that they have hard valves (shells) protecting their bodies. However, unlike bivalves, who have a left and right shell arrangement, brachiopods have upper and lower shells (trust me, it makes sense anatomically). Their shells are hinged at the rear, while the front end can be opened for feeding or closed for protection. Most brachiopods have a stalk-like pedicle which projects from an opening near their hinge and anchors the animal to the sea floor (see 3rd image). Some brachiopods use their pedicle to emerge and retract into a burrow. They are filter feeders, using a lophophore to feed. However, unlike bryozoans and entoprocts, their lophophore is U-shaped. Some species do not have an anus, instead combining solid waste with mucus and periodically "sneezing” it out. Brachiopod lifespans can range from 3 to 30+ years. They only live in the ocean, in areas with cold water and low light, and without strong currents or waves, Some are commonly known as “lamp shells.”

There are two major categories of brachiopod; articulate and inarticulate. Articulate refers to the tooth-and-groove structure at the hinge of the shell, which inarticulate brachiopods lack. Inarticulate brachiopods have larvae that look like miniature adults with extended lophophores (seen in gif below), which live as plankton for months before growing too heavy and sinking to the sea floor. Articulate brachiopods have larvae which look like blobs with a yolk sack and live as plankton for a few days before metamorphosing.

Brachiopods have existed since the early Cambrian, but lost about 2/3 of their once great diversity during the Permian-Triassic extinction event. Today there are about 100 living genera, though there are 5,000 fossil genera.

Propaganda under the cut:

Brachiopods hit their peak in the Paleozoic era, occupying many ecological niches and being the most abundant filter-feeders and reef-builders. After losing most of their diversity in the Triassic, they’ve lost this position to bivalves. But we must never forget the Old Kings of Shell.

The smallest living brachiopod, Gwynia, is only about 1 mm long and lives between grains of gravel.

The largest brachiopods known lived in the Carboniferous: Gigantoproductus and Titanaria could be 30 to 38 cm (12 to 15 in) wide. Today, most brachiopods range from 1 to 100 mm (0.04 to 3.9 in) long, with the largest being Magellania venosa.

Brachiopod flesh is apparently Not That Great, and not much preys on them. Even fossil brachiopods are rarely found with evidence of predation in the same way fossil bivalves are. Humans, however, do fish for one genera commercially, though on a small scale. Because of course we do.

Brachiopods are apparently very sensitive to pollution, and are good indicators of water quality.

Brachiopods are the state fossil of Kentucky. No specific species. Just all of them, I guess.

[lsopod]

i though isopods went extinct million sof years ago?

my friend

do you perhaps mean to say trilobites?

theeese funky little guys?

arthropods evolved into existence around 500 million years ago, trilobites being amongst the first of the arthropods. Trilobites did not survive the Permian-Triassic extinction event, but isopods did! Isopods are a more specific order of arthropod and evolved into existence around 358 million years ago and are still around today!From your giant deepsea isopod, to the silly little woodlice that you see under any rock or log they are extant!

[iidolomantis]

Mass Extinction Events Ranked By How Hot They Are

in my biology class earlier today the five mass extinction events were brought up, and i had to refrain from clapping and cheering. this is a list curated on passion.

DISCLAIMER: extinction events are not bad. extinction is, in most cases, a completely normal, morally-neutral evolutionary thing that just happens. human-accelerated extinction is not great, but background extinction is a process that is always happening. every mass extinction event in the past was necessary for life to get where it is today. please don’t get weird on my post. i just think it’s neat.

6. The Holocene Extinction - Right Now - TBA* - Habitat loss, overhunting, climate change boring. L. only extinction event caused by a single species (us). really just unoriginal. we’re not even directly killing most of them we’re just speeding up the background extinction rates. no pizzazz, no style. 0/10.

5. The Late Devonian Extinction - 372 mya - 70% of all species - Unknown this one is low for two reasons: one, we’re still trying to figure out what actually happened to explain the rapid drop in biodiversity, and while some people might find ambiguity attractive, i prefer honesty and emotional vulnerability. two, it was pretty centered on the oceans alone, and i want a little bit of flexibility, y’know? expand your range. i know you have potential. 3/10.

4. The Triassic-Jurassic Extinction - 201mya - 76% of all species - Volcanic eruptions leading to global warming and acidic oceans there’s been some debate about the cause of this one, but general scientific consensus agrees that those dastardly volcanoes are to blame. i’ll admit, i hold some fondness for this one just because it was kinda what allowed dinosaurs, crocodylomorphs, and pterosaurs to become top dog in the ages following. the whole ‘volcanic wasteland’ thing is also just a classic, though it loses some points for just doing the same thing but worse as its immediate predecessor (see no.2). some originality would be nice. 5/10.

3. The Ordovician-Silurian Extinction - 445 mya - 85% of all species - Rapid successive climate changes hey, this one’s for all the gilf lovers out there. this one is old, and while it would actually be more accurate to say 85% of all marine species, that’s just because most complex life hadn’t even gotten to land just yet. it’s also a little on the mysterious side. we know glaciation (leading to an ice age) caused the initial event, but what caused the glaciation? it’s trying to open up, but there are some skeletons in the closet. could be hot! 7/10.

2. The Permian-Triassic Extinction (aka the Great Dying) - 252mya - 90% of all species - Volcanic eruptions leading to global warming, toxic atmosphere, and sulfurous oceans for this one, i gotta give points on the name alone, y’know? i WISH that was my highschool nickname. also massive points just for being the biggest. i mean, 57% of all biological families. 81% of all marine species and 70% of terrestrial vertebrates… kind of an overachiever! hot! the OG world-ending volcanic wasteland. 9/10.

1. The Cretaceous-Paleocene Extinction (aka the K-pg extinction) - 66mya - 75% of all species - Asteroid impact followed by nuclear winter and volcanic eruptions you know her. you love her. that’s right, coming in at number one is THE ASTEROID THAT KILLED THE DINOSAURS**, BABEYYYYYY!!!! this one might not have been the biggest or most devastating, but you CANNOT deny the style of it. a rock bigger than mount everest, faster than a bullet, streaking in from the heavens? i can only hope whatever eventually takes us humans out has half as much flair. 10/10.

*we’re still in the predictions phase of actual numbers for this one, but current estimates put us at driving extinction rates up to 1000x faster than the norm since 1900, and 1 million out of 8 million species is currently threatened with extinction. bad!

**non-avian dinosaurs, specifically. birds are dinosaurs and doing just fine, mostly, except for the asterisk just above this one. um.

[a-dinosaur-a-day]

like, yeah, I could include the current one, but everyone would vote for it, and that's a boring poll