Jurassic period. jurassic mesozoic era jurassic biology

The Jurassic period is the middle of the Mesozoic era. This piece of history is primarily famous for its dinosaurs, it was very good time for all living things. During the Jurassic period, for the first time, reptiles ruled everywhere: in water, on land and in the air.
This period was named after a mountain range in Europe. The Jurassic period began about 208 million years ago. This period was more revolutionary than the Triassic. This revolutionism was with those estates that occurred with the earth's crust, because it was during the Jurassic period that the mainland of Pangea began to diverge. The climate has since become warmer and more humid. In addition, the level of water in the world's oceans began to rise. All this gave great opportunities for animals. Due to the fact that the climate became more favorable, plants began to appear on land. And corals began to appear in shallow waters.

The Jurassic period lasted from 213 to 144 million years ago. At the very beginning of the Jurassic period, the climate throughout the Earth was dry and warm. All around were deserts. But later heavy rains began to soak them with moisture. And the world became greener, lush vegetation began to flourish.
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 period, about 195 million years ago. throughout the northern hemisphere, the vegetation was rather monotonous. But already starting from the middle of the Jurassic period, about 170-165 million years ago, two (conditional) plant belts were formed: northern and southern. In the northern vegetation belt ginkgo and herbaceous ferns predominated. 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. Jurassic period ferns and cordaites are now occupied by tropical forests, consisting mainly of cycads. Cycads are a class of gymnosperms that dominated the green cover of the Jurassic 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 they were even initially identified as palm trees in the plant system.

In the Jurassic, ginkgo trees are also common - deciduous (which is unusual for gymnosperms) trees with an oak-like crown and small fan-shaped leaves. Only one species has survived to this day - ginkgo biloba. The first cypress and, possibly, spruce trees appear during the Jurassic period. coniferous forests Jurassic period were similar to modern ones.

In the Jurassic period, the Earth was established temperate climate. Even the arid zones were rich in vegetation. Such conditions were ideal for the reproduction of dinosaurs. Among them, lizards and ornithischians are distinguished.

Lizards moved on four legs, had five toes on their feet, and ate plants. Most of them had long neck, small head and 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. Chisel-shaped small teeth were densely located on the jaws of a small head. The brontosaurus lived in swamps, on the shores of lakes. Brontosaurus weighed about 30 tons and exceeded 20 in length. Lizard-footed dinosaurs (sauropods) were the largest land animals known so far. All of them were herbivores. Until recently, paleontologists believed that such heavy creatures were forced to spend most of their lives in the water. It was believed that on land, his tibia would "break" under the weight of a colossal carcass. However, the finds of recent years (in particular, footprints) indicate that sauropods preferred to roam in shallow water, and they also entered solid ground. In relation to body size, brontosaurs had an extremely small brain, weighing no more than a pound. In the region of the sacral vertebrae of the brontosaurus, there was an expansion of the spinal cord. Being much larger than the brain, it controlled the musculature of the hind limbs and tail.

Ornithischian dinosaurs are divided into bipedal and quadrupedal. different in size and appearance, they fed mainly on vegetation, but predators also appear among them.

Stegosaurs are herbivores. Stegosaurus is especially abundant in North America, from where several species of these animals are known, reaching a length of 6 m. The back was steeply convex, the height of the animal reached 2.5 m. The body was massive, although the stegosaurus moved on four legs, its forelimbs were much shorter rear. On the back, large bone plates rose in two rows, protecting the spinal column. At the end of the short, thick tail, used by the animal for defense, there were two pairs of sharp spikes. Stegosaurus was a vegetarian and had an exceptionally small head and a correspondingly tiny brain, little more than a walnut. Interestingly, the expansion of the spinal cord in the sacral region, associated with the innervation of powerful hind limbs, was much larger in diameter than the brain.
Many scaly lepidosaurs appear - small predators with beak-shaped jaws.

In the Jurassic period, flying lizards first appear. They flew with the help of a leathery shell stretched between the long finger of the hand and the bones of the forearm. Flying lizards were well adapted to flight. They had light tubular bones. The extremely elongated outer fifth finger of the forelimbs consisted of four joints. The first finger looked like a small bone or was completely absent. The second, third and fourth fingers consisted of two, rarely three bones and had claws. The hind limbs were quite strongly developed. They had sharp claws at their ends. The skull of flying lizards was relatively large, as a rule, elongated and pointed. In old lizards, the cranial bones fused and the skulls became similar to the skulls of birds. The premaxilla sometimes grew into an elongated toothless beak. Toothed lizards had simple teeth and sat in recesses. The largest teeth were in front. Sometimes they stick out to the side. This helped the lizards to catch and hold prey. The spine of animals consisted of 8 cervical, 10-15 dorsal, 4-10 sacral and 10-40 caudal vertebrae. The chest was wide and had a high keel. The shoulder blades were long, the pelvic bones were fused. The most characteristic representatives of flying lizards are pterodactyl and rhamphorhynchus.

Pterodactyls in most cases were tailless, different in size - from the size of a sparrow to a crow. They had wide wings and a narrow skull extended forward with a small number of teeth in the front. Pterodactyls lived in large flocks on the shores of the lagoons of the late Jurassic sea. During the day they hunted, and at nightfall they hid in trees or in rocks. The skin of pterodactyls was wrinkled and bare. They ate mainly fish, sometimes sea lilies, molluscs, and insects. In order to take off, pterodactyls had to jump off rocks or trees.
Rhamphorhynchus had long tails, long narrow wings, a large skull with numerous teeth. Long teeth of various sizes arched forward. The lizard's tail ended in a blade that served as a rudder. Ramphorhynchus could take off from the ground. They settled on the banks of rivers, lakes and seas, fed on insects and fish.

Flying lizards lived only in the Mesozoic era, and their heyday falls on the late Jurassic period. Their ancestors were apparently extinct ancient reptiles pseudosuchia. The long-tailed forms appeared before the short-tailed ones. At the end of the Jurassic, they became extinct.
It should be noted that flying lizards were not the ancestors of birds and bats. Flying lizards, birds and bats originated and developed each in their own way, and there are no relatives between them. family ties. The only thing they have in common is the ability to fly. And although they all acquired this ability due to a change in the forelimbs, the differences in the structure of their wings convince us that they had completely different ancestors.

The seas of the Jurassic period were inhabited by dolphin-like reptiles - ichthyosaurs. They had a long head, sharp teeth, big eyes surrounded by a bony ring. The length of the skull of some of them was 3 m, and the body length was 12 m. The limbs of ichthyosaurs consisted of bone plates. Elbow, metatarsus, hand and fingers did not differ much in shape from each other. About a hundred bone plates supported a wide flipper. Shoulder and pelvic girdle were poorly developed. There were several fins on the body. Ichthyosaurs were viviparous animals.

Along with ichthyosaurs lived plesiosaurs. Appeared in the Middle Triassic, they reached their peak already in the Lower Jurassic, in the Cretaceous they were common in all seas. They were divided into two main groups: long-necked with a small head (plesiosaurs proper) and short-necked with a fairly massive head (pliosaurs). The limbs turned into powerful flippers, which became the main organ of swimming. The more primitive Jurassic pliosaurs originate mainly from Europe. Plesiosaurus from the Lower Jura, reached a length of 3 m. These animals often came ashore to rest. Plesiosaurs were not as dexterous in water as pliosaurs. To a certain extent, this shortcoming was compensated by the development of a long and very flexible neck, with the help of which plesiosaurs could seize prey with lightning speed. They ate mainly fish and shellfish.
In the Jurassic period, new genera of fossil turtles appear, and at the end of the period, modern turtles.
Tailless frog-like amphibians lived in fresh water.

There were a lot of fish in the Jurassic seas: bony, rays, sharks, cartilaginous, ganoid. They had an internal skeleton made of flexible cartilaginous tissue impregnated with calcium salts: a dense bony scaly cover that protected them well from enemies, and jaws with strong teeth.
Of the invertebrates in the Jurassic seas, ammonites, belemnites, sea lilies were found. However, in the Jurassic period, there were much fewer ammonites than in the Triassic. The Jurassic ammonites also differ from the Triassic in their structure, with the exception of the phyloceras, which did not change at all during the transition from the Triassic to the Jura. Separate groups of ammonites have preserved mother-of-pearl to our time. Some animals lived in the open sea, others inhabited bays and shallow inland seas.

Cephalopods - belemnites - swam in whole flocks in the Jurassic seas. Along with small specimens, there were real giants - up to 3 m long.
The remains of internal shells of belemnites, known as "devil's fingers", are found in the sediments of the Jurassic period.
In the seas of the Jurassic period, bivalve mollusks, especially those belonging to the oyster family, also developed significantly. They start to form oyster jars. Significant changes are taking place sea urchins settled on reefs. Along with the round forms that have survived to this day, there lived bilaterally symmetrical, irregularly shaped hedgehogs. Their body was stretched in one direction. Some of them had a jaw apparatus.

The Jurassic seas were relatively shallow. The rivers brought muddy water into them, delaying gas exchange. Deep bays were filled with decaying remains and silt containing a large amount of hydrogen sulfide. That is why in such places the remains of animals, carried by sea currents or waves, are well preserved.
Many crustaceans appear: barnacles, decapods, leaf-legged crayfish, freshwater sponges, among insects - dragonflies, beetles, cicadas, bedbugs.

Deposits of coal, gypsum, oil, salt, nickel and cobalt are associated with the Jurassic deposits.

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Jurassic period- This is the second (middle) period of the Mesozoic era. It begins 201 million years before our times, lasts 56 million years and ends 145 million years ago (according to other sources, the duration of the Jurassic period is 69 million years: 213 - 144 million years). Named after mountains Yura, in which its sedimentary layers were first identified. Significant for the widespread flowering of dinosaurs.

The main subdivisions of the Jurassic period, its geography and climate

According to the classification adopted International Union geological sciences, The Jurassic period is divided into three divisions- Lower - Leias (stages - Gottangsky, Sinemursky, Plinsbachsky, Toarsky), Middle - Dogger (levels - Aalensky, Bayossky, Batsky, Callovian) and Upper Small (levels - Oxford, Kimmeridgsky, Tithonian).

Jurassic period	Departments	Tiers
	Leyas (Lower)	Goettansky
		Sinemursky
		Plinsbachsky
		Toarian
	Dogger (Medium)	Aalen
		Bayosian
		Bath
		Callovian
	Small (Upper)	Oxford
		Kimmeridge
		titonian

In this period, the division of Pangea into constituent blocks - the continents - continued. Upper Laurentia, which later became North America and Europe, finally separated from Gondwana, which again began to shift south. As a result, the connection between the global continents was broken, which had an important impact on the further evolution and development of flora and fauna. The differences that originated at that time are sharply expressed to this day.

Even more expanded as a result of the divergence of the continents, the Tethys Sea now occupied most of modern Europe. It originated from the Iberian Peninsula and, crossing the south and southeast of Asia diagonally, went into Pacific Ocean. Most of current France, Spain and England was under his warm waters. On the left, as a result of the separation of the North American sector of Gondwana, a depression began to emerge, which in the future became the Atlantic Ocean.

With the start of the Jurassic era average temperature on the globe gradually began to decline, and therefore in the lower section Jurassic climate was close to moderate - subtropical. But closer to the middle, the temperature began to rise again, and by the beginning of the Cretaceous period, the climate became greenhouse.

The ocean level rose and fell slightly throughout the Jurassic, but the average sea level was an order of magnitude higher than in the Triassic. As a result of the divergence of continental blocks, a great many small lakes were formed, in which both plant and animal life began to develop and progress very quickly, so that quantitative and quality level flora and fauna of the Jurassic period soon caught up and outstripped the level of the Permian to the point of global mass extinction.

sedimentation

With a drop in temperature, multiple precipitations began to fall abundantly throughout the earth, which contributed to the advancement of vegetation, and then the animal world, into the depths of the continents, which is due to Jurassic sedimentation. But the most intense for this period are the products of the formation of the earth's crust under the influence of continental shifts, and as a result, volcanic and other seismic activity. These are various igneous, clastic rocks. Large deposits of shale, sand, clay, conglomerates, limestone.

The warm and stable climate of the Jurassic period greatly contributed to the rapid development, formation and evolutionary improvement of both old and new life forms. (Fig. 1) have risen to a new level compared to the sluggish, not especially shining varieties, the Triassic.

Rice. 1 - Jurassic Animals

The Jurassic seas were full of various marine invertebrates. Especially numerous were belemnites, ammonites, all kinds of sea lilies. And although there were an order of magnitude fewer ammonites in the Jurassic than in the Triassic, they mostly had a more developed body structure than their ancestors from the previous era, with the exception of the phyloceras, which did not change at all during the millions of years of transition from the Triassic to the Jurassic. It was at that time that many ammonites acquired their indescribable mother-of-pearl coating, which has survived to this day. Ammonites were found in large quantities, both in distant oceanic depths and in coastal warm and inland seas.

Belemnites in the Jurassic era reached an unprecedented development. They huddled in flocks and plowed the depths of the sea in search of gaping prey. Some of them at that time reached three meters in length. The remains of their shells, nicknamed by scientists "devil's fingers" are found in the sediments of the Jurassic period almost everywhere.

Bivalve mollusks belonging to oyster varieties were also numerous. In that era, they began to form a kind of oyster jars. Numerous sea urchins, which abundantly inhabited reef areas at that time, also received an impetus in development. Some of them have successfully survived to our time. But many, such as hedgehogs of irregular shapes elongated along the length, which had a jaw apparatus, died out.

Insects have also taken a big step forward. Their visual, flying and other devices improved more and more. More and more varieties appeared among the barnacles, decapods, leaf-footed crustaceans, most of the freshwater sponges and caddisflies multiplied and evolved. Ground jurassic insects replenished with new varieties of dragonflies, beetles, cicadas, bedbugs, etc. Along with the emergence of a huge number of flowering plants, a large number of pollinating insects that feed on flower nectar began to appear.

But it was the reptiles that reached the greatest development in the Jurassic era - dinosaurs. By the middle of the Jurassic period, they completely took over all the land areas, displacing or destroying their reptilian predecessors, from which they originated, in pursuit of food.

AT sea depths already at the beginning of the Jurassic period reigned supreme dolphin-like ichthyosaurs. Their long heads had strong, oblong jaws studded with rows of sharp teeth, and large, highly developed eyes were framed by bone-plate rings. By the middle of the period, they turned into real giants. The length of the skull of some ichthyosaurs reached 3 meters, and the body length exceeded 12 meters. The limbs of these aquatic reptiles evolved under the influence of underwater life and consisted of simple bone plates. Elbows, metatarsus, hands and fingers ceased to differ from each other, one huge flipper supported more than a hundred bone plates of various sizes. The shoulder girdle, as well as the pelvic girdle, became underdeveloped, but this was not necessary, since additionally grown powerful fins provided them with mobility in the aquatic environment.

Another reptile that seriously and permanently settled in the depths of the sea was plesiosaur. They, like ichthyosaurs, originated in the seas as early as the Triassic period, but in the Jurassic period they branched into two varieties. Some had a long neck and a small head (plesiosaurs), while others had an order of magnitude larger head and a much shorter neck, which made them look more like underdeveloped crocodiles. Both, unlike ichthyosaurs, still needed to rest on land, and therefore often crawled out onto it, becoming the prey of land giants there, such as, for example, a tyrannosaurus rex or herds of smaller predatory reptiles. Very nimble in the water, on land they were clumsy fur seals our time. Pliosaurs were much more agile in the water, but what plesiosaurs lacked in agility was made up for by their long necks, thanks to which they instantly grabbed prey, no matter what position their body was in.

In the Jurassic period, all kinds of fish multiplied unusually. The water depths literally teemed with a motley variety of coral ray-finned, cartilaginous and ganoid. Sharks with stingrays were also diverse, which, due to their extraordinary agility, speed and agility, developed over hundreds of millions of years of evolution, still constituted Jurassic underwater reptile predators. Also during this period, many new varieties of turtles and toads appeared.

But the terrestrial variety of reptile dinosaurs was truly outstanding. (Fig. 2) were from 10 cm to 30 meters in height. Many of them were simple harmless herbivores, but often came across and ferocious predators.

Rice. 2 - Jurassic Dinosaurs

One of the largest herbivorous dinosaurs was brontosaurus(now Apatosaurus). His body weighed 30 tons, the length from head to tail reached 20 meters. And despite the fact that his height at the shoulders reached only 4.5 meters, with the help of a neck that reached a length of up to 5-6 meters, they perfectly ate tree foliage.

But the largest dinosaur of that era, as well as the absolute champion among all the animals of the Earth of all time, was a 50-ton herbivore. brachiosaurus. With a body length of 26 m, he had such a long neck that when it stretched up, his small head was 13 meters above the ground. To feed, this huge reptile needed to absorb up to 500 kg of green mass daily. It is noteworthy that with such a truly gigantic body size, his brain weighed no more than 450 grams.

It is appropriate to say a few words about predators, of which there were also many in the Jurassic period. The most gigantic and dangerous predator of the Jura is considered a 12-meter tyrannosaurus rex, but as scientists have proven, this predator was more opportunistic in its views on food. He rarely hunted, often preferring carrion. But they were truly dangerous. allosaurs. With a height of 4 meters and a length of 11 meters, these reptile predators hunted prey many times greater than them in terms of weight and other parameters. Often they, having huddled in a herd, attacked such herbivorous giants of that era as Camarasaurus (47 tons) and the aforementioned Apatosaurus.

Came across more small predators, for example, such as 3-meter dilophosaurus, weighing only 400 kg, but straying into a flock, attacking even larger predators.

In view of the ever-increasing danger from predatory individuals, evolution has rewarded some herbivorous individuals with formidable elements of protection. For example, such a herbivorous dinosaur as Kentrosaurus was endowed with elements of protection in the form of huge sharp spikes on the tail and sharp plates along the ridge. The spikes were so large that, with a strong blow, the Kentrosaurus would have pierced through such a predator as a Velociraptor or even a Dilophosaurus.

With all that animal world Jurassic has been carefully balanced. The herbivorous lizard population was controlled by predatory lizards, predators were kept in check by many smaller predators and aggressive herbivores like stegosaurs. Thus, the natural balance was maintained for many millions of years, and what caused the extinction of dinosaurs in the Cretaceous period is still not known.

By the middle of the Jurassic period, the airspace was filled with many flying dinosaurs, such as pterodactyls and other pterosaurs. They glide quite skillfully in the air, but in order to take to the skies, they need to climb imposing hills. These, for the most part, were not very mobile specimens of ancient mammals, but from the air they could very successfully track down and attack prey in a flocking manner. Smaller representatives of flying dinosaurs preferred to make do with carrion.

In the sediments of the Jurassic period, the remains of a fledged lizard Archeopteryx were found, which for a long time was considered by scientists to be the ancestor of birds. But, as recently scientifically proven, this variety of lizards was a dead end. Birds evolved mainly from other varieties of reptiles. Archeopteryx had a long feathered tail, jaws dotted with small teeth, and the feathered wings had developed fingers, with which the animal grabbed the branches. Archeopteryxes flew poorly, mainly gliding from branch to branch. Basically, they preferred to climb tree trunks, digging into their bark and branches with sharp curved claws. It is noteworthy that in our time, fingers on the wings remained only in the chicks of the hoatzin bird.

The first birds, in the form of small dinosaurs, jumped high either in their attempts to reach out for insects fluttering in the sky, or in order to escape from predators. In the process of evolution, they were increasingly overgrown with plumage, their jumps became longer and longer. In the process of jumping, future birds helped themselves more and more intensively, waving their forelimbs. Over time, their now wings, and not just forelimbs, acquired more and more powerful muscles, and the structure of their bones became hollow, as a result of which the overall weight of the birds became much lighter. And all this led to the fact that by the end of the Jurassic period, along with pterosaurs, a large number of all kinds of ancient birds plowed the airspace of the Jura.

In the Jurassic period, they actively multiplied and small mammals. But still, they were not allowed to express themselves in breadth, because the ubiquitous power of dinosaurs was too overwhelming.

Since, in the process of climate change, the vast deserts of the Triassic began to be abundantly irrigated with precipitation, this created the prerequisites for the advancement of vegetation even deeper into the continents, and closer to the middle of the Jurassic, almost the entire surface of the continents was covered with lush vegetation.

All low-lying places are abundantly overgrown with ferns, cicadas and coniferous thickets. The coasts of the seas were occupied by araucaria, thuja and, again, cicadas. Also, vast land masses were occupied by ferns and horsetails. Despite the fact that by the beginning of the Jurassic period, the vegetation on the continents of the northern hemisphere was relatively uniform, by the middle of the Jurassic, two main belts of plant masses, already established and strengthened, were formed - the northern and southern.

northern belt was notable for the fact that at that time it was formed mainly by ginkgo plants mixed with herbaceous ferns. With all that is half the whole vegetation northern latitudes jurassic consisted of Ginkgo varieties, today only one species of these plants has miraculously survived.

Southern belt were mainly cycads and tree ferns. Generally Jurassic period plants(Fig. 3) more than half still consisted of various ferns. Horsetails and club mosses of those times almost did not differ from the current ones. In those places where cordaite and ferns grew massively during the Jurassic, this moment growing tropical cycad jungle. Of the gymnosperms, cycads were the most common in the Jurassic. Today they can be found only in tropical and subtropical zones. It was them, reminiscent of modern palm trees with their crowns, that most herbivorous dinosaurs ate.

Rice. 3 - Plants of the Jurassic period

In the Jurassic period, deciduous Ginkgoaceae first began to appear in the northern latitudes. And in the second half of the period, the first spruce and cypress trees appeared. The coniferous forests of the Jura looked very much like modern ones.

Minerals of the Jurassic period

The most pronounced minerals related to the Jurassic period are European and North American chromite deposits, Caucasian and Japanese copper-pyrite deposits, Alpine deposits of manganese ores, tungsten ores of the Verkhoyansk-Chukotka region, Transbaikalia, Indonesia, North American Cordilleras. Also to this era can be attributed deposits of tin, molybdenum, gold and other rare metals scattered everywhere, formed in the late Cimmerian era and thrown to the surface due to granitoid mechanisms associated with the separation of the continents that took place at the end of the Jurassic period. Numerous and ubiquitous iron ore deposits. There are deposits of uranium ores on the Colorado Plateau.

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jurassic, jurassic movie
Jurassic period (Yura) - 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 Jurassic system. different regions planets, these deposits differ in composition, genesis, and appearance.

For the first time deposits given period have been 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.

1 Jurassic subdivision
- 1.1 Geological events
- 1.2 Climate
- 1.3 Vegetation
- 1.4 Marine organisms
- 1.5 Land animals
2 notes
3 Literature
4 Links

Jurassic subdivision

The Jurassic system is subdivided into 3 divisions and 11 tiers:

system	Department	tier	Age, million years ago
Chalk	Lower	Berriasian	less
	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 2015

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

The drooping cycad (Cycas revoluta) is one of the cycads growing in our time
Ginkgo biloba (Ginkgo biloba). Botanical illustration from Siebold and Zuccarini's Flora Japonica, Sectio Prima, 1870

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 among palm trees in his plant system.

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 and temperate zone. The ferns gradually disappeared.

marine organisms

Leedsichthys and liopleurodon

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

Reconstruction of Archeopteryx,
Oxford University Museum

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. On his wings were free fingers (from 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), dominated on land, lived in forests, lakes, swamps. The range of differences between them is so great that family ties between their species 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. Of the latter, the Jurassic period saw the heyday of sauropods - diplodocus, brachiosaurs, apatosaurs, and camarasaurus. Sauropods were hunted by other sauropod dinosaurs, namely large theropods.

Brachiosaurus

Ceratosaurus

pseudotribos

Notes

International Stratigraphic Scale (version January 2013) on the website of the International Commission on Stratigraphy

Literature

Jordan N. N. The development of life on earth. - M.: Enlightenment, 1981.
Karakash N.I.,. Jurassic system and period // 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

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Jurassic Information About

From 213 to 144 million years ago.
By the beginning of the Jurassic period, the giant supercontinent Pangea was in the process of active decay. South of the equator, there was still a single vast mainland, which was again called Gondwana. Later it also split into parts that formed today's Australia, India, Africa and South America. Terrestrial animals of the northern hemisphere could no longer move freely from one continent to another, but they still spread freely throughout the southern supercontinent.
At the beginning of the Jurassic period, the climate throughout the Earth was warm and dry. Then, as heavy rains began to soak the ancient Triassic deserts, the world became greener again, with more lush vegetation. In the Jurassic landscape, horsetails and club mosses grew thickly, which survived from the Triassic period. Palm-shaped bennettites have also been preserved. In addition, there were many griots around. Extensive forests of seed, common and tree ferns, as well as fern-like cycads, spread from water bodies inland. Coniferous forests were still common. In addition to ginkgo and araucaria, the ancestors of modern cypresses, pines and mammoth trees grew in them.

Life in the seas.

As Pangea began to split apart, new seas and straits arose, in which new types of animals and algae found refuge. Gradually, fresh sediments accumulated on the seabed. Many invertebrates settled in them, such as sponges and bryozoans (sea mats). In warm and shallow seas, other important events. There were giant Coral reefs, sheltering numerous ammonites and new varieties of belemnites (old relatives of the current octopuses and squids).
On land, in lakes and rivers, many different types crocodiles, widely dispersed around the globe. There were saltwater crocodiles with long snouts and sharp teeth for catching fish. Some of their varieties even grew flippers instead of legs to make it easier to swim. Tail fins allowed them to reach greater speed in water than on land. There are also new types sea turtles. Evolution also gave rise to many species of plesiosaurs and ichthyosaurs that competed with new, fast-moving sharks and extremely mobile bony fish.

This cycad is a living fossil. It almost does not differ from its relatives that grew on Earth in the Jurassic period. Now cycads are found only in the tropics. However, 200 million years ago they were much more widespread.
Belemnites, living projectiles.

Belemnites were close relatives of modern cuttlefish and squid. They had a cigar-shaped internal skeleton. Its main part, consisting of a calcareous substance, is called the rostrum. At the anterior end of the rostrum there was a cavity with a fragile multi-chambered shell, which helped the animal to stay afloat. This entire skeleton was placed inside the soft body of the animal and served as a solid frame to which its muscles were attached.
The solid rostrum is best preserved in fossil form than any other body part of a belemnite, and it is usually this that falls into the hands of scientists. But sometimes, non-roster fossils are also found. The first such finds in early XIX in. baffled many experts. They guessed that they were dealing with the remains of belemnites, but without the accompanying rostrum, these remains looked rather strange. The answer to this mystery turned out to be extremely simple, as soon as more data was collected about the way the ichthyosaurs feed - the main enemies of the belemnites. Apparently, rostless fossils were formed when an ichthyosaur swallowed a whole school of belemnites and regurgitated the soft parts of one of the animals, while its hard internal skeleton remained in the stomach of a predator.
Belemnites, like modern octopuses and squids, developed an inky liquid and used it to create a "smoke screen" when they tried to escape from predators. Scientists have also discovered fossilized belemnite ink sacs (organs in which a supply of ink liquid was stored). One of the scientists of the Victorian era, William Buckland, even managed to extract some of the ink from fossil ink bags, which he used to illustrate his book Bridgewater Treatise.

Plesiosaurs, barrel-shaped marine reptiles with four wide flippers that they rowed through the water like oars.
Glued fake.

No one has yet been able to find a whole fossil belemnite (soft part plus rostrum), although in the 70s. 20th century in Germany, a rather ingenious attempt was made to fool the whole scientific world with a clever forgery. Whole fossils, allegedly taken from a quarry in southern Germany, were purchased by several museums at a very high price, before it was discovered that in all cases the calcareous rostrum was carefully glued to the fossil soft parts of the belemnites!
This famous photo, made in 1934 in Scotland, was recently declared a fake. Nevertheless, for fifty years it fueled the enthusiasm of those who considered the Loch Ness monster to be a living plesiosaur.

Mary Anning (1799 - 1847) was only 2 years old when she discovered the first ichthyosaur fossil at Lyme Regis in Dorothy, England. Subsequently, she was lucky to find also the first fossil skeletons of a plesiosaur and a pterosaur.
This child could find
Glasses, pins, nails.
But got in the way
Ichthyosaurus bones.

Born for Speed

The first ichthyosaurs appeared in the Triassic. These reptiles were ideally adapted to life in the shallow seas of the Jurassic period. They had a streamlined body, fins of various sizes and long narrow jaws. The largest of them reached a length of about 8 m, but many species did not exceed a person in size. They were excellent swimmers, feeding mainly on fish, squid and nautiloids. Although ichthyosaurs belonged to reptiles, their fossil remains suggest that they were viviparous, that is, they produced ready-made offspring, like mammals. Perhaps the young ichthyosaurs were born in the open sea, like whales.
Another group of predatory reptiles, also widespread in the Jurassic seas, are the plesiosaurs. Their long-necked varieties lived near the surface of the sea. Here they hunted for shoals of very large fish with their flexible necks. Short-necked species, the so-called pliosaurs, preferred life at great depths. They ate ammonites and other molluscs. Some large pliosaurs appear to have preyed on smaller plesiosaurs and ichthyosaurs as well.

Ichthyosaurs looked like exact copies dolphins, except for the shape of the tail and an extra pair of fins. For a long time scientists believed that all the fossil ichthyosaurs that fell into their hands had a damaged tail. In the end, they guessed that the spine of these animals had a curved shape and at its end was a vertical tail fin (in contrast to the horizontal fins of dolphins and whales).
Life in the Jurassic air.

In the Jurassic period, the evolution of insects accelerated dramatically, and as a result, the Jurassic landscape eventually filled with endless buzzing and crackling, which were emitted by many new types of insects, crawling and flying everywhere. Among them were predecessors
modern ants, bees, earwigs, flies and wasps. Later, in the Cretaceous period, there was a new evolutionary explosion, when insects began to "make contacts" with the newly appeared flowering plants.
Until that time, real flying animals were found only among insects, although attempts to master the air environment were also observed in other creatures that learned to plan. Now whole hordes of pterosaurs have risen into the air. These were the first and largest flying vertebrates. Although the first pterosaurs appeared at the end of the Triassic, their true "rise" occurred precisely in the Jurassic period. Light skeletons of pterosaurs consisted of hollow bones. The first pterosaurs had tails and teeth, but in more highly developed individuals, these organs disappeared, which made it possible to significantly reduce their own weight. In some fossil pterosaurs, hair is guessed. Based on this, it can be assumed that they were warm-blooded.
Scientists still disagree about the lifestyle of pterosaurs. For example, it was originally believed that pterosaurs were a kind of "living gliders" that soared like vultures above the ground in the streams of rising hot air. Perhaps they even skimmed over the surface of the ocean, drawn by sea winds, like modern albatrosses. However, now some experts believe that pterosaurs could flap their wings, that is, actively fly, like birds. Perhaps some of them even walked like a bird, while others dragged their bodies along the ground or slept in the nesting places of relatives, hanging upside down, like bats.

Data obtained from the analysis of the fossilized stomachs and dung (coprolites) of ichthyosaurs indicate that their diet consisted mainly of fish and cephalopods (ammonites, nautiloids and squids). The contents of the stomachs of ichthyosaurs made it possible to make an even more curious discovery. Small hard spikes on the tentacles of squid and other cephalopods, apparently, caused a lot of inconvenience to ichthyosaurs, since they were not digested and, accordingly, could not freely pass through them. digestive system. As a result, the spikes accumulated in the stomach, and from them scientists manage to find out what the animal ate throughout its life. So, when studying the stomach of one of the fossil ichthyosaurs, it turned out that he swallowed at least 1500 squids!
How birds learned to fly.

There are two main theories trying to explain how birds learned to fly. One of them claims that the first flights took place from the bottom up. According to this theory, it all began with the fact that bipedal animals, the predecessors of birds, ran and jumped high into the air. Perhaps this is how they tried to escape from predators, or maybe they caught insects. Gradually, the feathered area of the "wings" became large, the jumps, in turn, lengthened. The bird did not touch the ground longer and remained in the air. Add to this the flapping movements of the wings - and it will become clear to you how, after a long time, these "pioneers of aeronautics" learned to stay in flight for a long time, and their wings gradually acquired properties that allowed them to support the body in the air.
However, there is another theory, the opposite, according to which the first flights took place from top to bottom, from trees to the ground. Potential "flyers" had to first climb to a considerable height, and only then throw themselves into the air. In this case, the first step on the way to flying should have been planning, since with this type of movement, energy costs are extremely insignificant - in any case, much less than with the "running-jumping" theory. The animal does not need to make additional efforts, because when planning it is pulled down by the force of the earth's gravity.

The first fossil Archeopteryx was discovered two years after the publication of Charles Darwin's On the Origin of Species. This important discovery was another confirmation of Darwin's theory that evolution is very slow and that one group of animals gives birth to another, undergoing a series of successive transformations. famous scientist and close friend Darwin, Thomas Huxley, predicted the existence of an animal like Archeopteryx in the past, even before its remains fell into the hands of scientists. In fact, Huxley described this animal in detail before it was discovered!
Step flight.

One scientist proposed an extremely curious theory. It describes a series of stages through which the "pioneers of aeronautics" had to pass in the course of evolutionary process which eventually turned them into flying animals. According to this theory, once one of the groups of small reptiles, called pro-topts, switched to an arboreal way of life. Perhaps the reptiles climbed trees because it was safer there, or easier to get food, or more convenient to hide, sleep, equip nests. It was cooler on the treetops than on the ground, and these reptiles developed warm-bloodedness and feathers for better thermal insulation. Any extra long feathers on the limbs were welcome - they provided additional thermal insulation and increased the surface area of the winged "arms".
In turn, soft, feathered forelimbs softened the impact on the ground when the animal lost balance and fell from tall tree. They slowed down the fall (acting as a parachute), and also provided a more or less soft landing, serving as a natural shock absorber. Over time, these animals began to use feathered limbs as proto-wings. Further transition from para-
from the late stage to the planning stage should have become a completely natural evolutionary step, after which it was the turn of the last, flight, stage, which Archeopteryx almost certainly reached.

"Early" bird
The first birds appeared on Earth towards the end of the Jurassic period. The most ancient of them, Archeopteryx, looked more like a small feathered dinosaur than a bird. She had teeth and a long bony tail adorned with two rows of feathers. Three clawed fingers protruded from each of its wings. Some scientists believe that Archeopteryx used its clawed wings to climb trees, from where it periodically flew back to the ground. Others believe that he lifted himself off the ground using gusts of wind. In the process of evolution, the skeletons of birds became lighter, and the toothy jaws were replaced by a toothless beak. They developed a "wide sternum, to which the powerful muscles necessary for flight were attached. All these changes made it possible to improve the structure of the bird's body, giving it an optimal structure for flight.
The first fossil find of Archeopteryx was a single feather, discovered in 1861. Soon, a whole skeleton of this animal (and with feathers!) was found in the same area. Since then, six fossilized skeletons of Archeopteryx have been discovered, some complete and others only fragmentary. The last such find dates back to 1988.

Age of dinosaurs.

The very first dinosaurs appeared over 200 million years ago. Over the 140 million years of their existence, they have evolved into a wide variety of species. Dinosaurs spread across all continents and adapted to life in a wide variety of habitats, although none of them lived in holes, did not climb trees, did not fly or swim. Some dinosaurs were no bigger than squirrels. Others weighed more than fifteen adult elephants combined. Some waddled heavily on all fours. Others ran faster on two legs than Olympic sprint champions.
65 million years ago, all dinosaurs suddenly became extinct. However, before disappearing from the face of our planet, they left us in the rocks a detailed "report" about their life and their time.
The most common group of dinosaurs in the Jurassic were the prosauropods. Some of them evolved into the largest land animals of all time - sauropods ("lizards"). These were the "giraffes" of the dinosaur world. They probably spent all their time eating leaves from the tops of trees. To provide vital energy for such a huge body, an incredible amount of food was required. Their stomachs were capacious digestive containers, continuously processing mountains of plant food.
Later, many varieties of small, swift-footed dinos appeared.
saurs - the so-called hadrosaurs. These were the "gazelles" of the dinosaur world. They plucked the undersized vegetation with their horny beaks and then chewed it up with strong molars.
The largest family of large carnivorous dinosaurs were the megalosaurids, or "huge lizards". The Megalosaurid was a ton-weight monster with huge, sharp, saw-toothed teeth that it used to tear through the flesh of its victims. Based on some of the fossilized footprints, his toes were pointing inward. It may have waddle like a giant duck, swinging its tail from side to side. Megalosaurids populated all areas the globe. Their fossils have been found in places as far apart as North America, Spain and Madagascar.
The early species of this family were, apparently, relatively small animals of a fragile constitution. And later megalosaurids became truly bipedal monsters. Their hind legs ended in three fingers armed with powerful claws. Muscular forelimbs helped in hunting large herbivorous dinosaurs. The sharp claws no doubt left horrific lacerations in the flank of the surprised prey. The powerful muscular neck of the predator allowed him to thrust his dagger-like fangs deep into the body of the prey with terrible force and pull out huge pieces of still warm meat from it.

In the Jurassic period, flocks of allosaurs robbed most of the earth's land. They, apparently, were a nightmarish sight: after all, each member of such a flock weighed more than a ton. Together, allosaurs could easily defeat even a large sauropod.

Jurassic period the most famous of all periods of the Mesozoic era. Most likely, such fame Jurassic period acquired thanks to the film "Jurassic Park".

Jurassic period tectonics:

At first jurassic the single supercontinent Pangea began to disintegrate into separate continental blocks. Shallow seas formed between them. Intense tectonic movements at the end Triassic and at the beginning jurassic periods contributed to the deepening of large bays, which 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 Jurassic period.

This is how the Earth looked at the end of the Triassic - the beginning jurassic
about 205 - 200 million years ago

This is how the Earth looked at the end of the Jurassic period, about 152 million years ago.

Climate and vegetation of the Jurassic period:

Volcanic activity of the end of the Triassic - the beginning jurassic caused the transgression of the sea. The continents separated and the climate in Jurassic period became wetter than in the Triassic. In place of the deserts of the Triassic period, in Jurassic period lush vegetation grew. Huge areas were covered with lush vegetation. The woods jurassic mainly consisted of ferns and gymnosperms.
Warm and humid climate jurassic contributed to the rapid development flora planets. 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 jurassic, about 195 million years ago throughout the northern hemisphere, the vegetation was rather monotonous. But already starting from the middle of the Jurassic, about 170-165 million years ago, two (conditional) plant belts were formed: northern and southern. Ginkgo and herbaceous ferns predominated in the northern vegetation belt. AT 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 jurassic and today are preserved in some corners of the wild. Horsetails and club mosses almost did not differ from modern ones. Places of growth of ferns and cordaites jurassic now occupied by tropical forests, consisting mainly of cycads. Cycads - a class of gymnosperms that prevailed in the green cover of the Earth jurassic. 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 they were even initially identified as palm trees in the plant system.
AT Jurassic period ginkgo trees are also common - deciduous (which is unusual for gymnosperms) trees with an oak-like crown and small fan-shaped leaves. Only one species has survived to this day - ginkgo biloba. The first cypress and, possibly, spruce trees appear during the Jurassic period. coniferous forests jurassic were similar to modern ones.

land animals Jurassic:

Jurassic period Dawn of the Age of Dinosaurs. 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. Diversity of dinosaur species Jurassic period it was great. They could be the size of a cat or a chicken, or they could reach the size of huge whales.

One of the fossils jurassic combining 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).

Jurassic Sky Kings:

AT Jurassic period winged lizards - pterosaurs reigned supreme in the air. They appeared as early as the Triassic, but their heyday fell on Jurassic period Pterosaurs were represented by two groups pterodactyls and rhamphorhynchus .

AT Jurassic period the first birds appear, or something in between birds and lizards. Creatures that appeared in Jurassic period and possessing 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.

But Jurassic period is not limited to animals alone. Thanks to climate change and the rapid development of flora jurassic, the evolution of insects accelerated dramatically, and as a result, the Jurassic landscape eventually filled with endless buzzing and crackling, which were emitted by many new types of insects, crawling and flying everywhere. Among them were the predecessors of modern ants, bees, earwigs, flies and wasps..

Masters of the seas of the Jurassic period:

As a result of the split of Pangea, in Jurassic period, new seas and straits were formed, in which new types of animals and algae developed.

Compared to the Triassic, Jurassic period 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. In warm and shallow seas jurassic other important events took place. AT Jurassic period a new type of reef communities is emerging, approximately the same as that which exists now. It is based on six-ray corals that appeared in the Triassic. The resulting giant coral reefs have sheltered numerous ammonites and new varieties of belemnites (old relatives of today's octopuses and squids). Also, many invertebrates settled in them, such as sponges and bryozoans (sea mats). Gradually, fresh sediments accumulated on the seabed.

On land, in lakes and rivers jurassic There were many different types of crocodiles, widely settled around the globe. There were also saltwater crocodiles with long snouts and sharp teeth for catching fish. Some of their varieties even grew flippers instead of legs to make it easier to swim. Tail fins allowed them to reach greater speed in water than on land. New species of sea turtles have also appeared.

All Jurassic Dinosaurs

Herbivorous dinosaurs: