Jurassic history. Encyclopedic short information about the Jurassic period. "Frost patterns on glass"
Jurassic geological period, Jura, Jurassic system, middle period of the Mesozoic. Began 200-199 million years ago. n. and ended with 144 million liters. n.
For the first time deposits of this period were discovered and described in the Jura (mountains in Switzerland and France), hence the name of the period. The deposits of the Jurassic period are very diverse: limestones, clastic rocks, shales, igneous rocks, clays, sands, conglomerates, formed in a variety of conditions. The deposits of that time are quite diverse: limestones, clastic rocks, shales, igneous rocks, clays, sands, conglomerates, formed in a variety of conditions.
Jurassic tectonics: At the beginning of the Jurassic, the single supercontinent Pangea began to break up into separate continental blocks. Shallow seas formed between them. Intensive tectonic movements at the end of the Triassic and at the beginning of the Jurassic contributed to the deepening of the large bays that gradually separated Africa and Australia from Gondwana. The gulf between Africa and America deepened. Depressions formed in Eurasia: German, Anglo-Paris, West Siberian. The Arctic Sea flooded the northern coast of Laurasia. It is thanks to this that the climate of the Jurassic period became more humid. In the Jurassic, the outlines of the continents begin to form: Africa, Australia, Antarctica, North and South America. And although they are located differently than now, they formed precisely in the Jurassic period.
Climate and vegetation of the Jurassic period
The volcanic activity of the end of the Triassic - the beginning of the Jurassic period caused the transgression of the sea. The continents separated and the climate in the Jurassic became more humid than in the Triassic. In place of the deserts of the Triassic period, lush vegetation grew in the Jurassic period. Huge areas were covered with lush vegetation. The forests of the Jurassic period mainly consisted of ferns and gymnosperms.
The warm and humid climate of the Jurassic period contributed to the violent development of the plant world of the planet.
Ferns, conifers, and cycads formed extensive marshy forests. Araucaria, arborvitae, cicadas grew on the coast. Ferns and horsetails formed vast forest areas. At the beginning of the Jurassic, about 195 million years. n. throughout the northern hemisphere, the vegetation was rather monotonous. Ginkgo and herbaceous ferns predominated in the northern vegetation belt. In the Jurassic period, Ginkgoaceae were very widespread. Groves of ginkgo trees grew throughout the belt.
In the southern vegetation belt, cycads and tree ferns predominated.
Ferns of the Jurassic period have survived to this day in some parts of the wild. Horsetails and club mosses almost did not differ from modern ones.
animals: Jurassic - the dawn of the dinosaur era. It was the violent development of vegetation that contributed to the emergence of many species of herbivorous dinosaurs. The growth in the number of herbivorous dinosaurs gave impetus to the growth in the number of predators. Dinosaurs settled all over the land and lived in forests, lakes, swamps. The range of differences between them is so great that family ties between them are established with great difficulty. The variety of dinosaur species in the Jurassic period was great. They could be the size of a cat or a chicken, or they could reach the size of huge whales.
The Jurassic period is the time of the dwelling of many famous dinosaurs. Of the lizards, these are Allosaurus and Diplodocus. Of the ornithischians, this is a stegosaurus.
In the Jurassic period, winged lizards - pterosaurs reigned supreme in the air. They appeared in the Triassic, but their heyday fell on the Jurassic period. Pterosaurs were represented by two groups of pterodactyls and rhamphorhynchus.
In the Jurassic period, the first birds appear, or something in between birds and lizards. Creatures that appeared in the Jurassic period and have the properties of lizards and modern birds are called Archeopteryx. The first birds are Archeopteryx, the size of a dove. Archeopteryx lived in forests. They fed mainly on insects and seeds.
Bivalves displace brachiopods from shallow waters. Brachiopod shells are replaced by oysters. Bivalve molluscs fill all the vital niches of the seabed. Many stop collecting food from the ground and move on to pumping water with the help of gills. Other important events took place in the warm and shallow seas of the Jurassic period.
The Jurassic period gave rise to many species of plesiosaurs and ichthyosaurs that competed with fast-moving sharks and extremely mobile bony fish. and in the depths of the sea, the leopleuradon patrolled its territory non-stop in search of food.
But one creature could rightfully be called the master of the Jurassic seas. This is a giant Liopleurodon weighing up to 25 tons. Liopleurodon was the most dangerous predator of the seas of the Jurassic period, and possibly in the entire history of the planet.
For the first time, deposits of this period were found in the Jura (mountains in Switzerland and France), hence the name of the period. The Jurassic period is subdivided into three divisions: leyas, doger and malm.
The deposits of the Jurassic period are quite diverse: limestones, clastic rocks, shales, igneous rocks, clays, sands, conglomerates formed in a variety of conditions.
Sedimentary rocks containing many representatives of fauna and flora are widely distributed.
Intensive tectonic movements at the end of the Triassic and at the beginning of the Jurassic contributed to the deepening of the large bays that gradually separated Africa and Australia from Gondwana. The gulf between Africa and America deepened. Depressions formed in Eurasia: German, Anglo-Paris, West Siberian. The Arctic Sea flooded the northern coast of Laurasia.
Intense volcanism and mountain-building processes led to the formation of the Verkhoyansk fold system. The formation of the Andes and the Cordillera continued. Warm sea currents have reached the Arctic latitudes. The climate became warm and humid. This is evidenced by the significant distribution of coral limestones and the remains of thermophilic fauna and flora. There are very few deposits of a dry climate: lagoonal gypsum, anhydrites, salts and red sandstones. The cold season already existed, but it was characterized only by a decrease in temperature. There was no snow or ice.
The climate of the Jurassic period depended on more than just sunlight. Numerous volcanoes and outpourings of magma on the bottom of the oceans heated up the water and the atmosphere, saturating the air with the steam of water, which then fell as rain on the land, flowing in stormy streams into lakes and oceans. Numerous freshwater deposits testify to this: white sandstones alternating with dark loams.
The warm and humid climate favored the flourishing of the plant world. Ferns, cicadas, and conifers formed extensive marshy forests. Araucaria, arborvitae, cicadas grew on the coast. Ferns and horsetails formed the undergrowth. In the Lower Jurassic, the vegetation throughout the northern hemisphere was fairly uniform. But already starting from the Middle Jurassic, two plant belts can be identified: the northern one, dominated by ginkgo and herbaceous ferns, and the southern one, with bennetites, cicadas, araucaria, and tree ferns.
The characteristic ferns of the mountain period were matonii, which have survived to this day in the Malay
archipelago. Horsetails and club mosses almost did not differ from modern ones. The place of extinct seed ferns and cordaites is occupied by cycads, which still grow in tropical forests.
Ginkgoaceae were also widely distributed. Their leaves turned to the sun with an edge and resembled huge fans. From North America and New Zealand to Asia and Europe, dense forests of coniferous plants grew - araucaria and bennetites. The first cypress and, possibly, spruce trees appear.
The representatives of the Jurassic conifers also include sequoia - a modern giant California pine. Currently, sequoias remain only on the Pacific coast of North America. Separate forms have been preserved. even more ancient plants, such as glassopteris. But there are few such plants, since they were supplanted by more perfect ones.
The lush vegetation of the Jurassic period contributed to the widespread distribution of reptiles. Dinosaurs have greatly evolved. Among them are lizard and ornithischian. Lizards moved on four legs, had five toes on their feet, and ate plants. Most of them had a long neck, a small head and a long tail. They had two brains: one small, in the head; the second is much larger in size - at the base of the tail.
The largest of the Jurassic dinosaurs was the brachiosaurus, reaching a length of 26 m, weighing about 50 tons. It had columnar legs, a small head, and a thick long neck. Brachiosaurs lived on the shores of the Jurassic lakes, fed on aquatic vegetation. Every day, the brachiosaurus needed at least half a ton of green mass.
Diplodocus is the oldest reptile, its length was 28 m. It had a long thin neck and a long thick tail. Like a brachiosaurus, diplodocus moved on four legs, the hind legs were longer than the front ones. Diplodocus spent most of its life in swamps and lakes, where it grazed and escaped from predators.
Brontosaurus was comparatively tall, had a large hump on its back and a thick tail. Its length was 18 m. The vertebrae of the brontosaurus were hollow. Chisel-shaped small teeth were densely located on the jaws of a small head. The brontosaurus lived in swamps, on the shores of lakes.
, conglomerates formed in a variety of conditions.
Jurassic subdivision
The Jurassic system is subdivided into 3 divisions and 11 tiers:
| system | the Department | tier | Age, million years ago | |
|---|---|---|---|---|
| Chalk | Lower | Berriasian | smaller | |
| Yura | Upper (malm) |
titonian | 152,1-145,0 | |
| Kimmeridge | 157,3-152,1 | |||
| Oxford | 163,5-157,3 | |||
| Medium (dogger) |
Callovian | 166,1-163,5 | ||
| Bath | 168,3-166,1 | |||
| Bayosian | 170,3-168,3 | |||
| Aalen | 174,1-170,3 | |||
| Lower (lias) |
Toarian | 182,7-174,1 | ||
| Plinsbachsky | 190,8-182,7 | |||
| Sinemursky | 199,3-190,8 | |||
| Goettansky | 201,3-199,3 | |||
| Triassic | Upper | Rhetic | more | |
| The division is given in accordance with IUGS as of April 2016 | ||||
Geological events
213-145 million years ago, the single supercontinent Pangea began to break up into separate continental blocks. Shallow seas formed between them.
Climate
The climate in the Jurassic period was humid and warm (and by the end of the period - arid in the equator).
Vegetation
In the Jurassic, vast areas were covered with lush vegetation, primarily a variety of forests. They mainly consisted of ferns and gymnosperms.
land animals
One of the fossil creatures that combine the features of birds and reptiles is Archeopteryx, or the first bird. For the first time, his skeleton was discovered in the so-called lithographic slates in Germany. The find was made two years after the publication of Charles Darwin's work " The Origin of Species" and became a strong argument in favor of the theory of evolution - it was initially considered a transitional form from reptiles to birds (in fact, it was a dead-end branch of evolution that was not directly related to real birds) . Archeopteryx flew rather poorly (planned from tree to tree), and was about the size of a crow. Instead of a beak, it had a pair of toothy, albeit weak jaws. It had free fingers on its wings (of modern birds, they were preserved only in hoatzin chicks).
In the Jurassic period, small, woolly warm-blooded animals live on Earth - mammals. They live next to dinosaurs and are almost invisible against their background. In the Jurassic, the division of mammals into monotremes, marsupials, and placentals took place.
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Notes
Literature
- Jordan N. N. development of life on earth. - M .: Enlightenment, 1981.
- Karakash N.I.,.// Encyclopedic Dictionary of Brockhaus and Efron: in 86 volumes (82 volumes and 4 additional). - St. Petersburg. , 1890-1907.
- Koronovsky N.V., Khain V.E., Yasamanov N.A. Historical Geology: Textbook. - M .: Academy, 2006.
- Ushakov S.A., Yasamanov N.A. Continental drift and climates of the Earth. - M .: Thought, 1984.
- Yasamanov N.A. Ancient climates of the Earth. - L.: Gidrometeoizdat, 1985.
- Yasamanov N.A. Popular paleogeography. - M .: Thought, 1985.
Links
- - A site about the Jurassic period, a large library of paleontological books and articles.
| ← | P a l e about h about th |
Mesozoic (252.2-66.0 Ma) | To a th n about h about th |
→ | ||
|---|---|---|---|---|---|---|
| ← | Triassic (252,2-201,3) |
Jurassic period (201,3-145,0) |
Cretaceous period (145,0-66,0) |
→ | ||
An excerpt characterizing the Jurassic period
Yes, happy Napoleon,Having learned through experiments what Bagration is,
He does not dare to trouble the Alcides of the Russians more ... "
But he had not yet finished his poems, when the loud butler proclaimed: "The meal is ready!" The door opened, a Polish rumbled from the dining room: “Thunder of victory resound, rejoice, brave Russian,” and Count Ilya Andreich, angrily looking at the author, who continued to read poetry, bowed to Bagration. Everyone got up, feeling that dinner was more important than poetry, and again Bagration went ahead of everyone to the table. In the first place, between the two Alexandrovs - Bekleshov and Naryshkin, which also mattered in relation to the name of the sovereign, Bagration was planted: 300 people were seated in the dining room according to rank and importance, who is more important, closer to the honored guest: as naturally as water spills deeper where the terrain is lower.
Just before dinner, Count Ilya Andreich introduced his son to the prince. Bagration, recognizing him, said a few awkward, awkward words, like all the words that he spoke that day. Count Ilya Andreich joyfully and proudly looked around at everyone while Bagration spoke with his son.
Nikolai Rostov with Denisov and a new acquaintance Dolokhov sat down together almost in the middle of the table. Opposite them, Pierre sat next to Prince Nesvitsky. Count Ilya Andreich sat opposite Bagration with other foremen and regaled the prince, personifying Moscow cordiality.
His labors were not in vain. His dinners, lean and modest, were excellent, but he still could not be completely calm until the end of dinner. He winked at the barman, gave orders to the footmen in a whisper, and, not without excitement, awaited each familiar dish. Everything was amazing. On the second course, together with the gigantic sterlet (on seeing which Ilya Andreich blushed with joy and shyness), the footmen began to clap corks and pour champagne. After the fish, which made some impression, Count Ilya Andreich exchanged glances with the other foremen. - "There will be a lot of toasts, it's time to start!" - he whispered and took the glass in his hands - he stood up. Everyone was silent and waited for what he would say.
- The health of the sovereign emperor! he shouted, and at the same moment his kind eyes were moistened with tears of joy and delight. At the same moment, they began to play: “The thunder of victory is heard.” Everyone got up from their seats and shouted hurray! and Bagration shouted hurray! in the same voice with which he shouted on the Shengraben field. The enthusiastic voice of young Rostov was heard from behind all 300 voices. He almost cried. “Health of the Sovereign Emperor,” he shouted, “hurray! He drank his glass in one gulp and threw it on the floor. Many followed his example. And the screams continued for a long time. When the voices fell silent, the lackeys picked up the broken dishes, and everyone began to sit down and, smiling at their cry, talk. Count Ilya Andreich got up again, looked at the note lying beside his plate, and proclaimed a toast to the health of the hero of our last campaign, Prince Pyotr Ivanovich Bagration, and again the count's blue eyes were moistened with tears. Hooray! again the voices of 300 guests shouted, and instead of music, choristers were heard singing a cantata composed by Pavel Ivanovich Kutuzov.
“All obstacles are in vain to the Russians,
Courage is a pledge of victory,
We have Bagrations,
All enemies will be at their feet,” etc.
The choristers had just finished, when more and more toasts followed, at which Count Ilya Andreevich became more and more emotional, and even more dishes were beating, and still more shouting. They drank to the health of Bekleshov, Naryshkin, Uvarov, Dolgorukov, Apraksin, Valuev, to the health of the elders, to the health of the manager, to the health of all club members, to the health of all club guests, and finally, separately, to the health of the founder of the dinner, Count Ilya Andreich. At this toast, the count took out a handkerchief and, covering his face with it, completely burst into tears.
Pierre sat opposite Dolokhov and Nikolai Rostov. He ate a lot and greedily and drank a lot, as always. But those who knew him briefly saw that some great change had taken place in him that day. He was silent all the time of dinner and, screwing up his eyes and wincing, looked around him or, stopping his eyes, with an air of complete absent-mindedness, rubbed the bridge of his nose with his finger. His face was sad and gloomy. He did not seem to see or hear anything going on around him, and he thought of one thing, heavy and unresolved.
This unresolved question that tormented him was the princess’s hints in Moscow about Dolokhov’s closeness to his wife and this morning the anonymous letter he received, in which it was said with that vile jocularity that is characteristic of all anonymous letters that he sees badly through his glasses, and that his wife's connection with Dolokhov is a secret only for him alone. Pierre resolutely did not believe either the hints of the princess or the letter, but he was now afraid to look at Dolokhov, who was sitting in front of him. Every time his gaze accidentally met Dolokhov's beautiful, insolent eyes, Pierre felt something terrible, ugly rising in his soul, and he rather turned away. Involuntarily recalling all the past of his wife and her relationship with Dolokhov, Pierre saw clearly that what was said in the letter could be true, could at least seem true, if it did not concern his wife. Pierre involuntarily recalled how Dolokhov, to whom everything was returned after the campaign, returned to St. Petersburg and came to him. Taking advantage of his revelry friendship with Pierre, Dolokhov came directly to his house, and Pierre placed him and lent him money. Pierre recalled how Helen, smiling, expressed her displeasure that Dolokhov was living in their house, and how Dolokhov cynically praised him for the beauty of his wife, and how from that time until his arrival in Moscow he was not separated from them for a minute.
“Yes, he is very handsome,” thought Pierre, I know him. It would be a special charm for him to dishonor my name and laugh at me, precisely because I worked for him and despised him, helped him. I know, I understand what salt in his eyes this must give to his deceit, if it were true. Yes, if it were true; but I do not believe, have no right, and cannot believe.” He recalled the expression that Dolokhov's face assumed when moments of cruelty were found on him, like those in which he connected the quarterly with a bear and let him into the water, or when he challenged a man to a duel for no reason, or killed the driver's horse with a pistol . This expression was often on Dolokhov's face when he looked at him. “Yes, he is a bully,” thought Pierre, it doesn’t mean anything to him to kill a person, it should seem to him that everyone is afraid of him, he should be pleased with this. He must think that I am afraid of him. And really I am afraid of him, ”thought Pierre, and again with these thoughts he felt something terrible and ugly rising in his soul. Dolokhov, Denisov and Rostov were now sitting opposite Pierre and seemed very cheerful. Rostov chatted merrily with his two friends, one of whom was a dashing hussar, the other a well-known brat and rake, and occasionally looked mockingly at Pierre, who at this dinner struck with his concentrated, absent-minded, massive figure. Rostov looked unkindly at Pierre, firstly, because Pierre in his hussar eyes was a civilian rich man, the husband of a beauty, in general a woman; secondly, because Pierre, in the concentration and distraction of his mood, did not recognize Rostov and did not answer his bow. When they began to drink the health of the sovereign, Pierre, thinking, did not get up and did not take a glass.
Jurassic period (Jurassic)- the middle (second) period of the Mesozoic era. It began 201.3 ± 0.2 Ma ago and ended 145.0 Ma ago. It continued in this way for about 56 million years. The complex of deposits (rocks) corresponding to a given age is called the Jurassic system. In different regions of the planet, these deposits differ in composition, genesis, and appearance.
For the first time deposits of this period were described in the Jura (mountains in Switzerland and France); hence the name of the period. The deposits of that time are quite diverse: limestones, clastic rocks, shales, igneous rocks, clays, sands, conglomerates, formed in a variety of conditions.
Flora
In the Jurassic, vast territories were covered with lush vegetation, primarily with various forests. They mainly consisted of ferns and gymnosperms.
Cycads - a class of gymnosperms that prevailed in the green cover of the Earth. Now they are found in the tropics and subtropics. Dinosaurs roamed under the shade of these trees. Outwardly, cycads are so similar to low (up to 10-18 m) palm trees that even Carl Linnaeus placed them in his system of plants among palm trees.
In the Jurassic period, groves of gingko trees grew throughout the then temperate zone. Ginkgoes are deciduous (unusually for gymnosperms) trees with an oak-like crown and small, fan-shaped leaves. Only one species has survived to this day - ginkgo biloba.
Very diverse were conifers, similar to modern pines and cypresses, which flourished at that time not only in the tropics, but had already mastered the temperate zone. The ferns gradually disappeared.
Fauna
marine organisms
Compared with the Triassic, the population of the seabed has changed a lot. Bivalves displace brachiopods from shallow waters. Brachiopod shells are replaced by oysters. Bivalve molluscs fill all the vital niches of the seabed. Many stop collecting food from the ground and move on to pumping water with the help of gills. A new type of reef communities is emerging, approximately the same as it exists now. It is based on six-ray corals that appeared in the Triassic.
Land animals of the Jurassic period
One of the fossil creatures that combine the features of birds and reptiles is Archeopteryx, or the first bird. For the first time, his skeleton was discovered in the so-called lithographic slates in Germany. The discovery was made two years after the publication of Charles Darwin's On the Origin of Species and became a strong argument in favor of the theory of evolution. Archeopteryx flew quite badly (planned from tree to tree), and was about the size of a crow. Instead of a beak, it had a pair of toothy, albeit weak jaws. It had free fingers on its wings (of modern birds, they were preserved only in hoatzin chicks).
In the Jurassic period, small, woolly warm-blooded animals - mammals - live on Earth. They live next to dinosaurs and are almost invisible against their background. In the Jura there was a division of mammals into monotremes, marsupials and placentals.
Dinosaurs (English Dinosauria, from other Greek δεινός - terrible, terrible, dangerous and σαύρα - lizard, lizard) lived in forests, lakes, swamps. The range of differences between them is so great that family ties between them are established with great difficulty. There were dinosaurs ranging in size from a cat to a whale. Different types of dinosaurs could move on two or four limbs. Among them were both predators and herbivores.
Scale
| Geological scale | |||
|---|---|---|---|
| Aeon | Era | Period | |
| F a n e R about h about th | Cenozoic | Quaternary | |
| Neogene | |||
| Paleogene | |||
| Mesozoic | Chalk | ||
| Yura | |||
| Triassic | |||
| Paleozoic | Permian | ||
| Carbon | |||
| Devonian | |||
| Silurus | |||
| Ordovician | |||
| Cambrian | |||
| D about to e m b R and th | P R about t e R about h about th | Neo- Proterozoic | Ediacaran |
| cryogeny | |||
| Tony | |||
| Meso- Proterozoic | Stenius | ||
| Ectasia | |||
| potassium | |||
| Paleo- Proterozoic | Statery | ||
| Orosirium | |||
| Riasius | |||
| siderius | |||
| BUT R X e th | neoarchean | ||
| Mesoarchean | |||
| paleoarchaean | |||
| Eoarchean | |||
| catarchean | |||
Jurassic subdivision
The Jurassic system is subdivided into 3 divisions and 11 tiers:
| system | the Department | tier | Age, million years ago | |
|---|---|---|---|---|
| Chalk | Lower | Berriasian | smaller | |
| Jurassic period | Upper (malm) | titonian | 145,0-152,1 | |
| Kimmeridge | 152,1-157,3 | |||
| Oxford | 157,3-163,5 | |||
| Medium (dogger) | Callovian | 163,5-166,1 | ||
| Bath | 166,1-168,3 | |||
| Bayosian | 168,3-170,3 | |||
| Aalen | 170,3-174,1 | |||
| Lower (lias) | Toarian | 174,1-182,7 | ||
| Plinsbachsky | 182,7-190,8 | |||
| Sinemursky | 190,8-199,3 | |||
| Goettansky | 199,3-201,3 | |||
| Triassic | Upper | Rhetic | more | |
| Subsections are given in accordance with IUGS as of January 2013 | ||||
Rostras of belemnites Acrofeuthis sp. Early Cretaceous, Hauterivian
Brachiopod shells Kabanoviella sp. Early Cretaceous, Hauterivian
Bivalve shell Inoceramus aucella Trautschold, Early Cretaceous, Hauterivian
Skeleton of a saltwater crocodile Stenosaurus, Steneosaurus boltensis Jaeger. Early Jurassic, Germany, Holzmaden. Among the saltwater crocodiles, the talattosuchian stenosaurus was the least specialized form. He had developed not flippers, but ordinary five-fingered limbs, like in land animals, although somewhat shortened. In addition, a powerful bone shell made of plates has been preserved on the back and belly.
Three of the specimens displayed on the wall (crocodile stenosaurus and two ichthyosaurs - stenopterygium and eurhinosaurus) were found at one of the world's largest localities of the Early Jurassic marine fauna HOLTSMADEN (about 200 million years ago; Bavaria, Germany). For several centuries, the development of shale was carried out here, which was used as a building and decorative material.
At the same time, a huge number of remains of invertebrate fish, ichthyosaurs, plesiosaurs and crocodiles were discovered. More than 300 ichthyosaur skeletons alone have been recovered.
Small flying lizards - sordes were numerous in the vicinity of Lake Karatau. They probably fed on fish and insects. On some specimens of sordes, remnants of the hairline have been preserved, which is extremely rare in other localities.
Thecodonts- prenova group for other archosaurs. The first representatives (1,2) were terrestrial predators with widely spaced limbs. In the process of evolution, some thecodonts acquired a semi-vertical and vertical position of their paws with a quadrupedal mode of locomotion (3,5,6), others - in parallel with the development of bipedality (2,7,8). Most thecodonts were terrestrial, but some of them were amphibious (6).
crocodiles close to thecodonts. Early crocodiles (1,2,9) were terrestrial animals, marine forms with flippers and a tail fin also existed in the Mesozoic (10), and modern crocodiles are adapted to an amphibious lifestyle (11).
Dinosaurs- the central and most striking group of archosaurs. Large predatory carnosaurs (14,15) and small predatory cepurosaurs (16,17,18), as well as herbivorous ornithopods (19,20,21,22) were bipedal. Others used quadrupedal locomotion: sauropods (12,13), ceratopsians (23), stegosaurs (24) and antiposaurs (25). Sauropods and duck-billed dinosaurs (21) have, to varying degrees, adopted an amphibious way of life. One of the most highly organized among the archosaurs were flying pangolins (26,27,28), which had wings with a flying membrane, hair, and, possibly, a constant body temperature.
Birds- are considered direct descendants of the Mesozoic archosaurs.
Small land crocodiles, united in the Notosuchia group, were widespread in Africa and South America during the Cretaceous period.
Part of the skull of a sea lizard - pliosaurus. Pliosaurus cf. grandis Owen, Late Jurassic, Volga region. Pliosaurs, as well as their closest relatives - plesiosaurs, were perfectly adapted to the aquatic environment. They were distinguished by a large head, a short neck and long, powerful flipper-like limbs. Most of the pliosaurs had dagger-like teeth, and they were the most dangerous predators of the seas of the Jurassic period. This sample, 70 cm long, is only the front third of the pliosaurus skull, and the total length of the animal was 11-13 m. The pliosaurus lived 150-147 million years ago.
Larva of the Coptoclava beetle, Coptoclava longipoda Ping. This is one of the most dangerous predators in the lake.
Apparently, in the middle of the Cretaceous, the conditions in the lakes changed dramatically and many invertebrates had to go to rivers, streams, or temporary reservoirs (caddis flies, whose larvae build tube houses from grains of sand; Bottom sediments of these reservoirs are not preserved, flowing waters wash them away, destroying the remains of animals and plants. Organisms that migrated to such habitats disappear from the fossil record.
Houses of grains of sand, which were built and carried by caddisfly larvae, are very characteristic of the Early Cretaceous lakes. In later eras, such houses are found mainly in flowing waters.
Larvae of the caddisfly Terrindusia (reconstruction)
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Jurassic geological period, Jura, Jurassic system, middle period of the Mesozoic. It began 206 million years ago and lasted 64 million years.
For the first time deposits of the Jurassic period were described in the Jura (mountains in Switzerland and France), hence the name of the period. The deposits of that time are quite diverse: limestones, clastic rocks, shales, igneous rocks, clays, sands, conglomerates, formed in a variety of conditions.
190-145 million years ago, during the Jurassic period, the single supercontinent Pangea began to break up into separate continental blocks. Shallow seas formed between them.
Climate
The climate in the Jurassic period was humid and warm (and by the end of the period - arid in the equator).
In the Jurassic period, vast areas were covered with lush vegetation, primarily a variety of forests. They mainly consisted of ferns and gymnosperms.
cycads- a class of gymnosperms that prevailed in the green cover of the Earth. Now they are found here and there in the tropics and subtropics. Dinosaurs roamed under the canopy of these trees. Outwardly, cycads are so similar to low (up to 10-18 m) palm trees that even Carl Linnaeus placed them among palm trees in his plant system.
In the Jurassic period, groves of ginkgo trees grew throughout the then temperate zone. Ginkgoes are deciduous (unusually for gymnosperms) trees with an oak-like crown and small, fan-shaped leaves. Only one species has survived to this day - ginkgo biloba. Very diverse were conifers, similar to modern pines and cypresses, which flourished at that time not only in the tropics, but had already mastered the temperate zone.
marine organisms
Compared with the Triassic, the population of the seabed has changed a lot. Bivalves displace brachiopods from shallow waters. Brachiopod shells are replaced by oysters. Bivalve molluscs fill all the vital niches of the seabed. Many stop collecting food from the ground and move on to pumping water with the help of gills. A new type of reef communities is emerging, approximately the same as it exists now. It is based on six-ray corals that appeared in the Triassic.
land animals
One of the fossil creatures of the Jurassic period, combining the features of birds and reptiles, is Archeopteryx, or the first bird. For the first time, his skeleton was discovered in the so-called lithographic slates in Germany. The discovery was made two years after the publication of Charles Darwin's On the Origin of Species and became a strong argument in favor of the theory of evolution. Archeopteryx still flew rather poorly (planned from tree to tree), and was about the size of a crow. Instead of a beak, it had a pair of toothy, albeit weak jaws. It had free fingers on its wings (of modern birds, they were preserved only in hoatzin chicks).
In the Jurassic period, small, woolly warm-blooded animals - mammals - live on Earth. They live next to dinosaurs and are almost invisible against their background.
Dinosaurs of the Jurassic period ("terrible lizards" from Greek) lived in ancient forests, lakes, swamps. The range of differences between them is so great that family ties between them are established with great difficulty. They could be the size of a cat or a chicken, or they could reach the size of huge whales. Some of them moved on four limbs, while others ran on their hind legs. Among them were clever hunters and bloodthirsty predators, but there were also harmless herbivorous animals. The most important feature common to all their species is that they were land animals.