The Jurassic Period began as a large extinction took place at the end of the Triassic period, approximately 208-200 ma, and later extended to 144 million years ago, roughly 64 ma to 56 ma total. At the beginning, the continent, Pangaea, began to separate significantly for the first time. This may have given cause to the mass extinction, as the separation would have triggered a great deal of volcanic activity. The resulting environment gave way to what may be considered the golden age of the ruling dinosaurs. The Jurassic period is divided into the following subdivisions:
A Shifting Climate and Developing Oceans
At the start of the period, the breakup of the supercontinent Pangaea continued and accelerated. Laurasia, the northern half, broke up into North America and Eurasia. Gondwana, the southern half, began to break up by the mid-Jurassic. The eastern portion—Antarctica, Madagascar, India, and Australia—split from the western half, Africa and South America. New oceans flooded the spaces in between. Mountains rose on the seafloor, pushing sea levels higher and onto the continents.
All this water gave the previously hot and dry climate a humid and drippy subtropical feel. Dry deserts slowly took on a greener hue. Palm tree-like cycads were abundant, as were conifers such as araucaria and pines. Ginkgoes carpeted the mid- to high northern latitudes, and podocarps, a type of conifer, were particularly successful south of the Equator. Tree ferns were also present.
The oceans, especially the newly formed shallow interior seas, teemed with diverse and abundant life. At the top of the food chain were the long-necked and paddle-finned plesiosaurs, giant marine crocodiles, sharks, and rays. Fishlike ichthyosaurs, squidlike cephalopods, and coil-shelled ammonites were abundant. Coral reefs grew in the warm waters, and sponges, snails, and mollusks flourished. Microscopic, free-floating plankton proliferated and may have turned parts of the ocean red.
Fauna
Dinosaurs continued as the dominant species and evolved to be gigantic. Many titanic sauropods became common including the Seismosaurus, and the Brachiosaurus. These were pursued by large predators like the Ceratosaurus, and the well-known Allosaurus. These large dinosaurs may have influenced the evolution of the first armored dinosaurs like the Stegosaurus.
In the air, pterosaurs were common; they ruled the skies, filling many ecological roles now taken by birds. Within the undergrowth were various types of early mammals, as well as tritylodonts, lizard-like sphenodonts, and early lissamphibians.
Dinosaur Groups
Saurischia (“lizard-hipped” dinosaurs) contains two main groups:
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Sauropodomorpha includes both the “prosauropods” and the Sauropoda. Prosauropods were probably a paraphyletic (artificial) group of largely herbivorous, dominantly bipedal dinosaurs such as Plateosaurus. The Sauropoda were long-necked, long-tailed, enormous herbivorous dinosaurs such as Brachiosaurus, Diplodocus, and Apatosaurus.
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Theropoda consists of the carnivorous dinosaurs. The Theropoda includes some extinct dinosaurs such as Tyrannosaurus rex and Dilophosaurus. Birds descended from Theropoda.
Ornithischia (“bird-hipped” dinosaurs) contains three primary groups:
- Thyreophora includes the various armored dinosaurs such as Stegosaurus and Ankylosaurus.
- Marginocephalia consists mainly of the pachycephalosaurs (bone heads) and the ceratopsians (horned dinosaurs) such as Triceratops.
- Ornithopoda includes not only small bipedal plant eaters like Hypsilophodon but also the often large hadrosaurs (duck-billed dinosaurs) like Maiasaura and Edmontosaurus.
Marine Life
During the Jurassic period, the primary vertebrates living in the sea were fish and marine reptiles. The latter include ichthyosaurs, who were at the peak of their diversity, plesiosaurs, pliosaurs, and marine crocodiles of the families Teleosauridae and Metriorhynchidae. Numerous turtles could be found in lakes and rivers.
In the invertebrate world, several new groups appeared, including rudists (a reef-forming variety of bivalves) and belemnites. Calcareous sabellids (Glomerula) appeared in the Early Jurassic. The Jurassic also had diverse encrusting and boring (sclerobiont) communities, and it saw a significant rise in the bioerosion of carbonate shells and hardgrounds. Especially common is the ichnogenus (trace fossil) Gastrochaenolites.
During the Jurassic period, about four or five of the twelve clades of planktonic organisms that exist in the fossil record either experienced a massive evolutionary radiation or appeared for the first time.
Flora
The arid, continental conditions characteristic of the Triassic steadily eased during the Jurassic period, especially at higher latitudes; the warm, humid climate allowed lush jungles to cover much of the landscape. Gymnosperms were relatively diverse during the Jurassic period. The Conifers in particular dominated the flora, as during the Triassic; they were the most diverse group and constituted the majority of large trees.
Extant conifer families that flourished during the Jurassic included the Araucariaceae, Cephalotaxaceae, Pinaceae, Podocarpaceae, Taxaceae and Taxodiaceae. The extinct Mesozoic conifer family Cheirolepidiaceae dominated low latitude vegetation, as did the shrubby Bennettitales. Cycads were also common, as were ginkgos and Dicksoniaceous tree ferns in the forest. Smaller ferns were probably the dominant undergrowth. Caytoniaceous seed ferns were another group of important plants during this time and are thought to have been shrub to small-tree sized. Ginkgo plants were particularly common in the mid- to high northern latitudes. In the Southern Hemisphere, podocarps were especially successful, while Ginkgos and Czekanowskiales were rare.
End
Near the end of the Jurassic period several species died out giving rise to the Cretaceous period. This transition was not as violent as the mass extinction at the beginning of the Jurassic period nor as devastation as what would come near the end of the Cretaceous. However, it led to another era and bid farewell to one of the most dynamic epochs of earth's history.
Walking With Dinosaurs Episode 2 - A Time of the Titans :biggus-piggus:
Walking With Dinosaurs Episode 3 - Cruel Sea :fishe:
Jurassic Era (Part two) : the age of Dinosaurs :shocked-dino:
Jurassic Era (Part one) : the ocean :croc-pog:
How Did Dinosaurs Get So Huge? PBS eons
:big-honk:
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Aww yissss making a tofu stir fry during this blizzard, and playing some Uncharted 4
"WHy DONT YOU GET A REAL JOB!!!"
The real jobs:
Spreadsheet Taster at the Consulting Firm
Person Who Exists at the Marketing Company
Email Manager
just wanted to say to the dude who made all these paleo age whatever Megathreads that I've read every single one of them, and now I have like 20+ wiki pages open on Pangea, these dabbing ancient super-oceans and the theory of continental drift and I wanna be a paleogeologist. Fuck, thanks man.
Giving my cousin shit because she's apparently lived in the south long enough that she forgot why you take off your shoes at the door in winter. She and her new husband tracked salt all over the house. He's a lifelong southerner and can't be expected to know better, but this isn't her first snowstorm. Smdh
"What's in it for me as a property owner?"
Things a real person said to me in real life with their mouth.
“What’s in it for me as a property owner?”
depends if they want to die or not
Oh, I miss those. I do got arm warmers, now that I think of it. But getting yelled at for touching people with my icicle fingers is much more fun.
my bf likes doing that to me so i started conniving ways to get his finger to go up my nose or something so he'll be grossed out
oh dont worry, hes seen way, WAY worse. i had a pretty nasty hospital visit after getting a stomach virus lmao. he was a good little, very confused, trooper during that
Some Americans just have that "I probably hate the police, but if you put a gun and a badge in my hand, it would be like the 9/11 of Trayvon Martins." vibe
Paranoid about covid, estranged from my family, finished two years of therapy and I'm not depressed for the first time ever. I'm literally so fucking happy to do fuck all this Christmas. I'm gonna use my home gym, read Mao, and go for a nature walk. Merry Christmas.
Watching people hyperfixates on the alien whale part of Avatar 2 really shows how horrendous media literacy is today.
"Iraq war is bad because save the whales"
If Aesop's Fables are released today people would be like "That's stupid, animals can't talk"
*sin bell dings* “plot hole: the hare takes a nap in the middle of the friggin race? I’ve never seen that at the Olympics!”
They had the general mech-suit lady explicitly say "We're doing settler colonialism now," right at the start of the film. How did people get stuck on this being about Iraq?
haven't seen the second one yet - literally just rewatched the first one for the first time in 10 years and it was a lot better than i expected it to be/ remembered it being - but even if the movie were just an allegory for iraq that wouldnt be an unreasonable statement. talking about the environmental impact of the american imperial adventures is a good thing to do, the US military is the world's #1 polluter after all. and wasn't the defining image of the gulf wars endless fields of burning oil wells?
a lot of people are sick with not covid right now, worst flu season in ever and also really bad rsv outbreaks
triple pandemics yaaaay!!!
"Uh, you can't actually sense when you have pissed your pants because human skin does not have a wetness sensor" shut the fuck up if I cover you in gasoline and light you on fire I'm pretty sure you can sense it even though your skin doesn't have an "on fire sensor" fuking think for even a second before you say this dumb stuff
Imagine naming your kid Buzz
That's not a name. What are you, a bee?
You know times are tough when they lock up the fake air pods behind the glass with the alarm.
South Africa folks