Jurassic period, description of the Jurassic period, dinosaurs of the Jurassic period, lizards of the Jurassic period. Jurassic period, description of the Jurassic period, dinosaurs of the Jurassic period, lizards of the Jurassic period What historical period follows the Jurassic

, conglomerates formed in a variety of conditions.

Jurassic System Division

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

system	Department	tier	Age, million years ago
Chalk	Lower	Berriasian	less
Yura	Upper (malm)	Titonian	152,1-145,0
		Kimmeridge	157,3-152,1
		Oxford	163,5-157,3
	Average (dogger)	Callovian	166,1-163,5
		Bathian	168,3-166,1
		Bayocian	170,3-168,3
		Aalensky	174,1-170,3
	Lower (lias)	Toarsky	182,7-174,1
		Pliensbachian	190,8-182,7
		Sinemyursky	199,3-190,8
		Hettangian	201,3-199,3
Triassic	Upper	Rhetic	more
Divisions are given according to 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 region).

Vegetation

During the Jurassic, vast areas were covered with lush vegetation, primarily diverse forests. They mainly consisted of ferns and gymnosperms.

Land animals

One of the fossil creatures that combines the characteristics of birds and reptiles is Archeopteryx, or the first bird. His skeleton was first discovered in the so-called lithographic shales in Germany. The discovery was made two years after the publication of Charles Darwin's work "On the Origin of Species" and became a strong argument in favor of the theory of evolution - it was initially considered transitional form from reptiles to birds (in fact, this was a dead-end branch of evolution, not directly related to real birds). Archeopteryx flew rather poorly (gliding from tree to tree), and was approximately the size of a crow. Instead of a beak, it had a pair of toothy, albeit weak, jaws. There were free fingers on his wings (from modern birds they are preserved only in hoatzin chicks).

During the Jurassic period, small, furry, warm-blooded animals called mammals lived on Earth. They live next to dinosaurs and are almost invisible against their background. During the Jurassic period, the division of mammals into monotremes, marsupials and placentals occurred.

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Notes

Literature

• Iordansky N. N. Development of life on earth. - M.: Education, 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.: Mysl, 1984.
• Yasamanov N.A. Ancient climates of the Earth. - L.: Gidrometeoizdat, 1985.
• Yasamanov N.A. Popular paleogeography. - M.: Mysl, 1985.

Links

• - Site about the Jurassic period, a large library of paleontological books and articles.

←	P A l e O h O th	Mesozoic (252.2-66.0 million years ago)			TO A th n O h O th	→
←		Triassic (252,2-201,3)	Jurassic period (201,3-145,0)	Cretaceous period (145,0-66,0)		→

An excerpt characterizing the Jurassic period

The trees stood bare and featureless, lazily moving their drooping, thorny branches. Further behind them stretched the joyless, burnt-out steppe, getting lost in the distance behind a wall of dirty, gray fog... Many gloomy, drooping human beings restlessly wandered back and forth, senselessly looking for something, not paying any attention to the world around them, which, and however, it did not evoke the slightest pleasure so that one would want to look at it... The whole landscape evoked horror and melancholy, seasoned with hopelessness...
“Oh, how scary it is here...” Stella whispered, shuddering. – No matter how many times I come here, I just can’t get used to it... How do these poor things live here?!
– Well, probably these “poor things” were too guilty once if they ended up here. No one sent them here - they just got what they deserved, right? – still not giving up, I said.
“But now you’ll look...” Stella whispered mysteriously.
A cave overgrown with grayish greenery suddenly appeared in front of us. And out of it, squinting, came a tall, stately man who in no way fit into this wretched, chilling scenery...
- Hello, Sad! – Stella greeted the stranger affectionately. - I brought my friend! She doesn't believe what can be found here good people. And I wanted to show you to her... You don’t mind, do you?
“Hello, dear...” the man answered sadly, “But I’m not that good to show off to anyone.” You're wrong...
Oddly enough, I actually immediately liked this sad man for some reason. He exuded strength and warmth, and it was very pleasant to be around him. In any case, he was in no way like those weak-willed, grief-stricken people who surrendered to the mercy of fate, with whom this “floor” was chock-full.
“Tell us your story, sad man...” Stella asked with a bright smile.
“There’s nothing to tell, and there’s nothing particularly to be proud of...” the stranger shook his head. - And what do you need this for?
For some reason, I felt very sorry for him... Without knowing anything about him, I was already almost sure that this man could not have done anything truly bad. Well, I just couldn’t!.. Stela, smiling, followed my thoughts, which she apparently really liked...
“Well, okay, I agree - you’re right!..” Seeing her happy face, I finally honestly admitted.
“But you don’t know anything about him yet, but with him everything is not so simple,” Stella said, smiling slyly and contentedly. - Well, please tell her, Sad...
The man smiled sadly at us and said quietly:
– I’m here because I killed... I killed many. But it was not out of desire, but out of need...
I was immediately terribly upset - he killed!.. And I, stupid, believed it!.. But for some reason I stubbornly did not have the slightest feeling of rejection or hostility. I clearly liked the person, and no matter how hard I tried, I couldn’t do anything about it...
– Is it the same guilt – to kill at will or at necessity? – I asked. – Sometimes people have no choice, do they? For example: when they have to defend themselves or protect others. I have always admired heroes - warriors, knights. I generally always adored the latter... Is it possible to compare simple murderers with them?
He looked at me for a long time and sadly, and then also quietly answered:
- I don’t know, dear... The fact that I am here says that the guilt is the same... But the way I feel this guilt in my heart, then no... I never wanted to kill, I just defended my land, I was a hero there... But here it turned out that I was just killing... Is this right? I think no...
- So you were a warrior? – I asked hopefully. - But then, this is a big difference– you defended your home, your family, your children! And you don’t look like a murderer!..
- Well, we are all not like the way others see us... Because they see only what they want to see... or only what we want to show them... And about the war - I also first just as you thought, you were even proud... But here it turned out that there was nothing to be proud of. Murder is murder, and it doesn’t matter how it was committed.
“But this is not right!..” I was indignant. - What happens then - a maniac-killer turns out to be the same as a hero?!.. This simply cannot be, this should not happen!
Everything inside me was raging with indignation! And the man sadly looked at me with his sad, gray eyes, in which understanding was read...
“A hero and a murderer take lives in the same way.” Only, probably, there are “extenuating circumstances,” since a person protecting someone, even if he takes a life, does so for a bright and righteous reason. But, one way or another, they both have to pay for it... And it’s very bitter to pay, believe me...
– Can I ask you how long ago you lived? – I asked, a little embarrassed.
- Oh, quite a long time ago... This is the second time I’m here... For some reason, my two lives were similar - in both of them I fought for someone... Well, and then I paid... And it’s always just as bitter ... – the stranger fell silent for a long time, as if not wanting to talk about it anymore, but then he quietly continued. – There are people who love to fight. I always hated it. But for some reason, life is returning me to the same circle for the second time, as if I was locked in this, not allowing me to free myself... When I lived, all our peoples fought among themselves... Some seized foreign lands - others they defended the lands. Sons overthrew fathers, brothers killed brothers... Anything happened. Someone accomplished unimaginable feats, someone betrayed someone, and someone turned out to be simply a coward. But none of them even suspected how bitter the payment would be for everything they had done in that life...
– Did you have family there? – to change the subject, I asked. - Were there children?
- Certainly! But that was already so long ago!.. They once became great-grandfathers, then they died... And some are already living again. That was a long time ago...
“And you’re still here?!..” I whispered, looking around in horror.
I couldn’t even imagine that he had been existing here like this for many, many years, suffering and “paying” his guilt, without any hope of leaving this terrifying “floor” even before the time came for him to return to physical Earth!.. And there he will again have to start all over again, so that later, when his next “physical” life ends, he will return (perhaps here!) with a whole new “baggage”, bad or good, depending on how he will live his “next” earthly life... And he could not have any hope of freeing himself from this vicious circle (be it good or bad), since, having begun his earthly life, each person “dooms” himself to this endless, eternal a circular “journey”... And, depending on his actions, returning to the “floors” can be very pleasant, or very scary...

Our planet is several billion years old, and man appeared on it not so long ago. And millions of years ago, completely different creatures dominated the Earth - powerful, fast and huge. Certainly, we're talking about about dinosaurs that inhabited almost the entire surface of the planet many centuries ago. The number of species of these animals is quite large, and it can be said with certainty that dinosaurs and the Jurassic World as a whole were the most diverse. And this era can be considered the heyday of life for all flora and fauna.

Life is everywhere

The Jurassic period took place 200-150 million years ago. The climate at that time was quite hot. Dense vegetation, the absence of snow and cold meant that life on earth was everywhere: on land, in the air and in the water. High humidity air led to the violent growth of plants, which became food for herbivores, growing to gigantic sizes. But they, like smaller animals, served as food for predators, the diversity of which is quite interesting.

The level of the world's oceans was much higher than now, and the favorable climate led to a rich diversity of life in the water. The shallow waters were teeming with shellfish and small animals, which became food for the larger ones. sea ​​predators. Life in the air was no less intense. The flying dinosaurs of the Jurassic period - pterosaurs - took over the skies. But during the same period, the ancestors of modern birds appeared, in whose wings there were no leather membranes, but feathers were born.

Herbivorous dinosaurs

The Jurassic era gave the world many large reptiles. Most of them reached fantastically gigantic sizes. Most large dinosaur Jurassic period - diplodocus, which lived in the territory of the modern United States, reached a length of 30 meters and weighed almost 10 tons. It is noteworthy that the animal ate not only plant foods, but also stones. This was necessary so that small pebbles would grind vegetation and tree bark in the animal’s stomach. After all, Diplodocus's teeth were very small, no larger than a human fingernail, and could not help the animal thoroughly chew plant food.

An equally large brachiosaurus had a mass exceeding the weight of 10 elephants and reached 30 meters in height. This animal lived in the territory of modern Africa and ate leaves coniferous trees and cycads. Such a giant easily absorbed almost half a ton plant food per day and preferred to settle near bodies of water.

An interesting representative of the herbivores of this era, the centrosaurus, lived on the territory of modern Tanzania. This Jurassic dinosaur was interesting for its body structure. On the animal's back were large plates, and the tail is covered with large spines that help fight off predators. The animal was about 2 meters in height and up to 4.5 meters in length. Kentrosaurus weighed a little over half a ton, making it the most agile dinosaur.

Jurassic period

The diversity of herbivores leads to the emergence and large quantity predators, because nature always maintains balance. The largest and most bloodthirsty dinosaur of the Jurassic period, Allosaurus, reached a length of almost 11 meters and a height of 4 meters. This predator, weighing 2 tons, hunted in the United States and Portugal and earned the title of the fastest runner.

It fed not only on small animals, but, joining in groups, even hunted very large prey, such as apatosaurs or camarasaurs. To do this, a sick or young individual was separated from the herd by joint efforts, after which they were collectively devoured.

The fairly famous Dilophosaurus, which lived on the territory of modern America, reached three meters in height and weighed up to 400 kilograms.

A fast predator with characteristic ridges on its head, a fairly striking representative of that period, similar to tyrannosaurs. He hunted small dinosaurs, but in a pair or a flock he could attack an animal that was significantly larger than himself. Great maneuverability and speed allowed the Dilophosaurus to catch even a fairly fast and miniature Scutellosaurus.

Marine life

Land is not the only place that dinosaurs inhabited, and the Jurassic world in the water was also diverse and multifaceted. A bright representative of that era there was a plesiosaur. This waterfowl predatory lizard had a long neck and reached a length of up to 18 meters. The structure of the skeleton with a short but fairly wide tail and powerful fins resembling oars allowed this predator to develop higher speed and reign in the depths of the sea.

No less interesting sea ​​dinosaur Jurassic period - an ichthyosaur similar to a modern dolphin. Its peculiarity was that, unlike other lizards, this predator gave birth to live young and did not lay eggs. The ichthyosaur reached 15 meters in length and hunted smaller prey.

Kings of the sky

By the end of the Jurassic period, small pterodactyl predators conquered the heights of heaven. The wingspan of this animal reached one meter. The body of the predator was small and did not exceed half a meter; the weight of an adult individual reached 2 kilograms. The predator could not take off, and before it could fly, it had to climb onto a rock or ledge. The pterodactyl ate fish, which it could see at a considerable distance. But he himself sometimes became a victim of predators, because on land he was quite slow and clumsy.

Another representative of the flying dinosaurs was Rhamphorhynchus. Slightly larger than a pterodactyl, this predator weighed three kilograms and had a wingspan of up to two meters. Habitat - Central Europe. The peculiarity of this winged dinosaur was a long tail. Sharp teeth and powerful jaws made it possible to catch slippery and wet prey, and the basis of the animal’s diet was fish, shellfish and, surprisingly, small pterodactyls.

Living world

The world in that era amazes with its diversity: dinosaurs were far from the only population of the Earth at that time. And Jurassic animals of other classes were quite common. After all, it was then, thanks to good conditions, turtles appeared in the form that is now familiar to us. Frog-like amphibians multiplied and became food for small dinosaurs.

The seas and oceans were teeming with many species of fish, such as sharks, rays and other cartilaginous and bony fish. They are also belemnites, they formed the lowest link in the food chain, but their multi-membered population supported life in the aquatic space. During this period, crustaceans such as barnacles, phyllopods and freshwater sponges appear.

Intermediate

The Jurassic period is notable for the appearance of the ancestors of birds. Of course, Archeopteryx didn't look all that much like a modern bird; it was more like a feathered miniraptor.

But a later ancestor, also known as Longipteryx, already resembled a modern kingfisher. Although birds for that era are quite a rare occurrence, but it is they who give rise to a new round of evolution of the animal world. Dinosaurs of the Jurassic period (photo shown above) became extinct long ago, but even now, looking at the remains of such giants, you feel awe of these giants.

Jurassic geological period, Jura, Jurassic system, middle period Mesozoic. It began 206 million years ago and lasted 64 million years.

Jurassic deposits were first 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 wide 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 region).

During the Jurassic period, vast areas were covered with lush vegetation, primarily diverse forests. They mainly consisted of ferns and gymnosperms.

Cycads- a class of gymnosperms that predominated in the green cover of the Earth. Nowadays they are found here and there in the tropics and subtropics. Dinosaurs roamed under the shade of these trees. Externally, 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.

During the Jurassic period, groves of ginkgo trees grew throughout what was then temperate zone. Ginkgos are deciduous (unusual for gymnosperms) trees with an oak-like crown and small fan-shaped leaves. Only one species has survived to this day - Ginkgo biloba. Conifers were very diverse, 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 to the Triassic, the population of the seabed has changed greatly. Bivalves push out brachiopods from shallow waters. Brachiopod shells are replaced by oysters. Bivalve mollusks fill all life niches of the seabed. Many stop collecting food from the ground and switch to pumping water using their gills. Folds up new type reef communities, approximately the same as what exists now. Its basis is formed in the Triassic six-rayed corals.

Land animals

One of the fossil creatures of the Jurassic period that combines the characteristics of birds and reptiles is Archeopteryx, or the first bird. His skeleton was first discovered in the so-called lithographic shales 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 quite poorly (gliding from tree to tree), and was approximately 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, only hoatzin chicks have them).

During the Jurassic period, small, furry, warm-blooded animals called mammals lived 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, and 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 chicken, or they could reach the size of huge whales. Some of them walked on all fours, while others ran on their hind legs. Were among them clever hunters And bloodthirsty predators, but there were also harmless herbivorous animals. Key Feature common to all their species is that they were land animals.

From 213 to 144 million years ago.
By the beginning of the Jurassic period, the giant supercontinent Pangea was in the process of active disintegration. There was still a single vast continent south of the equator, 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 unhindered 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. The Jurassic landscape was thick with horsetails and club mosses, which had survived from the Triassic period. Palm-shaped bennettites are also preserved. In addition, there were many grios around. Vast forests of seed, common and tree ferns, as well as fern-like cycads, spread from bodies of water 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 break apart, new seas and straits emerged, in which new types of animals and algae found refuge. Gradually on seabed fresh sediments accumulated. They are home to many invertebrates, such as sponges and bryozoans (sea mats). In warm and shallow seas other things happened important events. Giant ones formed there Coral reefs, sheltering numerous ammonites and new varieties of belemnites (old relatives of today's octopuses and squids).
On land, in lakes and rivers, there lived many different types crocodiles, widely spread across 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 swimming more convenient. The tail fins allowed them to develop greater speed in the water than on land. New species of sea turtles have also appeared. Evolution also produced many species of plesiosaurs and ichthyosaurs, competing with new, fast-moving sharks and extremely agile bony fish.

This cycad is a living fossil. It is almost no different from its relatives that grew on Earth during the Jurassic period. Nowadays, 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 calcareous substance, is called the rostrum. At the front end of the rostrum there was a cavity with a fragile multi-chambered shell that helped the animal 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 preserved in fossil form better than all other parts of the belemnite body, and it is usually the one that falls into the hands of scientists. But sometimes fossils without rostra are also found. The first such finds in early XIX V. have baffled many experts. They guessed that they were dealing with the remains of belemnites, but without the accompanying rostra these remains looked rather strange. The solution to this mystery turned out to be extremely simple, as soon as more data was collected about the feeding method of ichthyosaurs - the main enemies of belemnites. Apparently, the growthless fossils were formed when an ichthyosaur, having swallowed a whole school of belemnites, regurgitated the soft parts of one of the animals, while its hard internal skeleton remained in the stomach of the predator
Belemnites, like modern octopuses and squids, produced an inky liquid and used it to create a “smoke screen” when trying to escape from predators. Scientists have also discovered fossilized ink sacs of belemnites (organs in which a supply of ink liquid was stored). To one of the scientists victorian era, William Buckland, even managed to extract some ink from fossilized ink sacs, which he used to illustrate his book, The Bridgewater Treatise.

Plesiosaurs, barrel-shaped marine reptiles with four broad flippers that they used to row through the water like oars.
Glued fake.

No one has yet managed to find a complete fossil belemnite (soft part plus rostrum), although in the 70s. XX century in Germany a rather ingenious attempt was made to fool the whole scientific world with the help of skillful forgery. Whole fossils, allegedly obtained from one of the quarries in southern Germany, were purchased by several museums at very high prices before it was discovered that in all cases the limestone rostrum had been carefully glued to the fossilized soft parts of the belemnites!
This famous photograph, taken in 1934 in Scotland, was recently declared a fake. Nevertheless, for fifty years it fueled the enthusiasm of those who believed that the Loch Ness monster was a living plesiosaur.

Mary Anning (1799 - 1847) was only two years old when she discovered the first fossil skeleton of an ichthyosaur at Lyme Regis in Doroeth, England. Subsequently, she was lucky enough to also find the first fossil skeletons of a plesiosaur and pterosaur.
This child could find
Glasses, pins, nails.
But then we got in the way
Ichthyosaur 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 different sizes and long narrow jaws. The largest of them reached a length of about 8 m, but many species were no larger than a person. They were excellent swimmers, feeding mainly on fish, squid and nautiloids. Although ichthyosaurs were reptiles, their fossil remains suggest that they were viviparous, that is, they gave birth to ready-made offspring, like mammals. Perhaps ichthyosaur babies were born on the open sea, like whales.
Another group of predatory reptiles, also widespread in Jurassic seas, - plesiosaurs. Their long-necked varieties lived near the surface of the sea. Here they hunted for schools of very large fish with the help of their flexible necks. Short-necked species, the so-called pliosaurs, preferred life at great depths. They ate ammonites and other mollusks. Some large pliosaurs apparently also hunted smaller plesiosaurs and ichthyosaurs.

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 fossil ichthyosaurs they came across had a damaged tail. In the end, they realized that the spine of these animals had a curved shape and at its end there was a vertical tail fin (unlike the horizontal fins of dolphins and whales).
Life in the Jurassic air.

During the Jurassic period, insect evolution accelerated dramatically, and as a result, the Jurassic landscape eventually became filled with the endless buzzing and crackling sounds of many new species of insects crawling and flying everywhere. Among them were predecessors
modern ants, bees, earwigs, flies and wasps. Later, in Cretaceous period, a new evolutionary explosion occurred when insects began to “establish contacts” with newly emerging flowering plants.
Until this time, real flying animals were found only among insects, although attempts to master the air environment were also observed among other creatures that learned to glide. Now whole hordes of pterosaurs have taken to the air. These were the first and largest flying vertebrates. Although the first pterosaurs appeared at the end of the Triassic, their true “takeoff” occurred precisely in the Jurassic period. The lung 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. Some fossil pterosaurs have visible hair. 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 hovered, like vultures, above the ground in currents of rising hot air. Perhaps they even glided over the surface of the ocean, drawn sea ​​winds like modern albatrosses. However, some experts now believe that pterosaurs could flap their wings, that is, actively fly, like birds. Perhaps some of them even walked like birds, while others dragged their bodies along the ground or slept in the nesting areas of their relatives, hanging upside down, like bats.

Data obtained from the analysis of fossilized stomachs and droppings (coprolites) of ichthyosaurs indicate that their diet consisted mainly of fish and cephalopods(ammonites, nautiloids and squids). The contents of the stomachs of ichthyosaurs allowed us to make an even more interesting discovery. Small hard spines on the tentacles of squids and other cephalopods, apparently, caused ichthyosaurs a lot of inconvenience, since they were not digested and, accordingly, could not pass freely through them. digestive system. As a result, the thorns accumulated in the stomach, and from them scientists are able to find out what a given animal has eaten throughout its life. Thus, when studying the stomach of one of the fossil ichthyosaurs, it turned out that it swallowed at least 1,500 squids!
How birds learned to fly.

There are two main theories that try 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 started with bipedal animals, the predecessors of birds, running and jumping 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 larger, and 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 their wings - and it will become clear to you how, after a long time, these “pioneers of aeronautics” learned to remain in flight for a long time, and their wings little by little acquired properties that allowed them to support their bodies 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 path to flight should have been planning, since with this type of movement the energy consumption is extremely insignificant - in any case, much less than with the “running-jumping” theory. The animal does not need to make additional efforts, because when gliding it is pulled down by the force of gravity.

The first fossil of Archeopteryx was discovered two years after the publication of Charles Darwin's book On the Origin of Species. This important discovery was further confirmation of Darwin's theory, which stated that evolution occurs very slowly and that one group of animals gives rise to another, undergoing a series of successive transformations. Famous scientist and close friend Darwin, Thomas Huxley, predicted the existence of an animal similar to Archeopteryx in the past, even before its remains fell into the hands of scientists. In fact, Huxley described this animal in detail when it had not yet been discovered!
Step flight.

One scientist proposed an extremely interesting theory. It describes a series of stages through which the "pioneers of aeronautics" must have passed during the evolutionary process that eventually turned them into flying animals. According to this theory, once upon a time one of the groups of small reptiles, called pro-topbirds, switched to an arboreal lifestyle. Perhaps the reptiles climbed into the trees because it was safer there, or it was easier to get food, or it was more convenient to hide, sleep, or build nests. It was cooler in 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 useful - after all, they provided additional thermal insulation and increased the surface area of ​​the wing-shaped “arms”.
In turn, the soft, feathered forelimbs softened the impact on the ground when the animal lost its balance and fell from the ground. 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-
The transition from the gliding stage to the gliding stage should have been 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 oldest 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, bird skeletons became lighter, and toothed jaws were replaced by toothless beaks. They developed a wide sternum, to which powerful muscles necessary for flight were attached. All these changes made it possible to improve the structure of the bird’s body, giving it a structure optimal for flight.
The first fossil find of Archeopteryx was a single feather, discovered in 1861. Soon, a complete skeleton of this animal (with feathers!) was found in the same area. Since then, six fossilized skeletons of Archeopteryx have been discovered: some complete, others only fragmentary. The last such find dates back to 1988.

Age of dinosaurs.

The very first dinosaurs appeared more than 200 million years ago. Over the 140 million years of their existence, they have evolved into many different species. Dinosaurs spread across all continents and adapted to life in the most different environments habitat, although none of them lived in burrows, climbed trees, flew or swam. Some dinosaurs were no larger than squirrels. Others weighed more than fifteen adult elephants combined. Some were swaying heavily on all fours. Others ran on two legs faster than Olympic champions in a sprint.
65 million years ago, all dinosaurs suddenly went extinct. However, before disappearing from the face of our planet, they left us rocks a detailed “report” about your life and your time.
The most common group of dinosaurs in the Jurassic period were prosauropods. Some of them developed into the largest land animals of all time - sauropods ("lizard-footed"). These were the "giraffes" of the dinosaur world. They probably spent all their time eating leaves from the treetops. To provide vital energy to such a huge body, an incredible amount of food was required. Their stomachs were capacious digestive containers that continuously processed mountains of plant food.
Later, many varieties of small, fleet-footed dinos appeared.
saurs - the so-called hadrosaurs. These were the gazelles of the dinosaur world. They nibbled low-growing vegetation with their horny beaks and then chewed it with their strong molars.
The largest family of large carnivorous dinosaurs were the megalosaurids, or "huge lizards." The megalosaurid was a monster weighing a ton, with huge, sharp saw-like teeth with which it tore the flesh of its victims. Judging by some of the fossilized footprints, his toes were turned inward. It may have waddled around like a giant duck, swinging its tail from side to side. Megalosaurids populated all areas globe. Their fossil remains 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 fragile build. And later megalosaurids became truly bipedal monsters. Their hind legs ended in three toes armed powerful claws. Muscular forelimbs helped in hunting large plant-eating dinosaurs. The sharp claws undoubtedly left terrible lacerations in the side of the surprised victim. The powerful muscular neck of the predator allowed him to terrible force plunge dagger-shaped fangs deep into the body of the prey and tear out huge pieces of still warm meat.

In the Jurassic period, packs of Allosaurus roamed 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 tectonics:

At first Jurassic period the single supercontinent Pangea began to break up 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 has deepened. Depressions formed in Eurasia: German, Anglo-Paris, West Siberian. The Arctic Sea flooded the northern coast of Laurasia. It was due to this that the climate of the Jurassic period became more humid. During the Jurassic period The outlines of the continents begin to form: Africa, Australia, Antarctica, North and South America. And although they are located differently than now, they were formed precisely in Jurassic period.

This is what the Earth looked like at the end of the Triassic - the beginning Jurassic period
about 205 - 200 million years ago

This is what the Earth looked like at the end of the Jurassic period around 152 million years ago.

Jurassic climate and vegetation:

Volcanic activity of the end of the Triassic - the beginning Jurassic period caused sea transgression. The continents were divided and the climate in Jurassic period became wetter than in the Triassic. On the site of deserts of the Triassic period, in Jurassic period lush vegetation grew. Huge areas were covered with lush vegetation. Forests Jurassic period consisted mainly of ferns and gymnosperms.
Warm and humid climate Jurassic period contributed to the rapid development flora planets. Ferns, conifers and cycads formed vast swampy forests. Araucarias, thujas, and cycads grew on the coast. Ferns and horsetails formed extensive forested areas. At first Jurassic period, about 195 million years ago Throughout the northern hemisphere, the vegetation was quite 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. The northern plant belt was dominated by ginkgo and herbaceous ferns. IN Jurassic period ginkgos were very widespread. Groves of ginkgo trees grew throughout the belt.
The southern plant belt was dominated by cycads and tree ferns.
Ferns Jurassic period and are still preserved in some corners today wildlife. Horsetails and mosses were almost no different from modern ones. Places where ferns and cordaites grow Jurassic period now occupied by tropical forests, consisting mainly of cycads. Cycads are a class of gymnosperms that predominated in the green cover of the Earth Jurassic period. Nowadays they are found here and there in the tropics and subtropics. Dinosaurs roamed under the shade of these trees. Externally, 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 Jurassic period Ginkgos 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 precisely during the brisk period. Coniferous forests Jurassic period were similar to modern ones.

Land animals Jurassic period:

Jurassic period- Dawn of the Age of Dinosaurs. It was the lush development of vegetation that contributed to the emergence of many species of herbivorous dinosaurs. The increase in the number of herbivorous dinosaurs gave impetus to the increase in the number of predators. Dinosaurs settled all over the land and lived in forests, lakes, and swamps. The range of differences between them is so great that family ties between them are established with great difficulty. Variety of dinosaur species in Jurassic period it was great. They could be the size of a cat or chicken, or they could reach the size of huge whales.

One of the fossil creatures Jurassic period, combining the characteristics of birds and reptiles, is Archeopteryx, or first bird. His skeleton was first discovered in the so-called lithographic shales 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 quite poorly (gliding from tree to tree), and was approximately 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, only hoatzin chicks have them).

Kings of the Jurassic Sky:

IN Jurassic period Winged lizards - pterosaurs - reigned supreme in the air. They appeared in the Triassic, but their heyday was precisely Jurassic period Pterosaurs were represented by two groups pterodactyls And Rhamphorhynchus .

Pterodactyls were in most cases tailless, varying in size - from the size of a sparrow to a crow. They had wide wings and a narrow skull elongated 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 rocks. The skin of pterodactyls was wrinkled and bare. They ate mainly fish or carrion, sometimes sea ​​lilies, mollusks, insects. In order to fly, pterodactyls were forced to jump from cliffs or trees.

IN Jurassic period the first birds or something in between birds and lizards appear. Creatures that appeared in Jurassic period and having the properties of lizards and modern birds are called Archeopteryx. The first birds were Archeopteryx, the size of a pigeon. Archeopteryx lived in forests. They ate mainly insects and seeds.

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

Masters of the Jurassic Seas:

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

Compared to the Triassic, in Jurassic period The population of the seabed has changed greatly. Bivalves displace brachiopods from shallow waters. Brachiopod shells are replaced by oysters. Bivalve mollusks fill all life niches of the seabed. Many stop collecting food from the ground and switch to pumping water using their gills. In warm and shallow seas Jurassic period Other important events also took place. IN Jurassic period a new type of reef community is emerging, approximately the same as what exists now. It is based on six-rayed corals that appeared in the Triassic. The resulting giant coral reefs sheltered numerous ammonites and new species of belemnites (old relatives of today's octopuses and squids). They also housed many invertebrates, such as sponges and bryozoans (sea mats). Gradually, fresh sediment accumulated on the seabed.

On land, in lakes and rivers Jurassic period There were many different species of crocodiles that spread widely across 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 swimming more convenient. The tail fins allowed them to develop greater speed in the water than on land. New species of sea turtles have also appeared.

All dinosaurs of the Jurassic period

Herbivorous dinosaurs: