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The Mesozoic consists of three periods: Triassic, Jurassic, Cretaceous.
in the triassic most of the land was above sea level, the climate was dry and warm. Due to the very dry climate in the Triassic, almost all amphibians disappeared. Therefore, the flowering of reptiles began, which were adapted to drought (Fig. 44). Among plants in the Triassic, strong development reached gymnosperms.
Rice. 44. Various types of reptiles of the Mesozoic era
Of the Triassic reptiles, turtles and tuatara have survived to this day.
The tuatara, preserved on the islands of New Zealand, is a real "living fossil". Over the past 200 million years, the tuatara has not changed much and has retained, like its Triassic ancestors, a third eye located in the roof of the skull.
Of reptiles, the rudiment of the third eye is preserved in lizards agamas and batbats.
Along with undoubted progressive features in the organization of reptiles, there was one very significant imperfect feature - unstable body temperature. In the Triassic period, the first representatives of warm-blooded animals appeared - small primitive mammals - tricodonts. They originated from ancient animal-toothed lizards. But tricodonts the size of a rat could not compete with reptiles, so they did not spread widely.
Yura named after a French city located on the border with Switzerland. In this period, the planet is "conquered" by dinosaurs. They mastered not only land, water, but also air. Currently, 250 species of dinosaurs are known. One of the most characteristic representatives of dinosaurs was a giant brachiosaurus. It reached a length of 30 m, weight 50 tons, had a small head, a long tail and neck.
In the Jurassic period, various types of insects and the first bird appear - archeopteryx. Archeopteryx is about the size of a crow. His wings were poorly developed, there were teeth, a long tail covered with feathers. In the Jurassic period of the Mesozoic, there were many reptiles. Some of their representatives began to adapt to life in the water.
The rather mild climate favored the development angiosperms.
Chalk- the name is given because of the powerful Cretaceous deposits formed from the remains of the shells of small marine animals. In this period, angiosperms arise and spread extremely rapidly, gymnosperms are forced out.
The development of angiosperms during this period was associated with the simultaneous development of pollinating insects and insect-eating birds. In angiosperms, a new reproductive organ arose - a flower that attracts insects with color, smell and nectar reserves.
At the end of the Cretaceous, the climate became colder, and the vegetation of the coastal lowlands perished. Together with the vegetation, herbivorous, predatory dinosaurs died. Large reptiles (crocodile) survived only in the tropical zone.
Under the conditions of a sharply continental climate and a general cooling, warm-blooded birds and mammals received exceptional advantages. The acquisition of live birth and warm-bloodedness were those aromorphoses that ensured the progress of mammals.
During the Mesozoic period, the evolution of reptiles developed in six directions:
1st direction - turtles (appeared in the Permian period, have a complex shell, fused with ribs and breast bones);
5th direction - plesiosaurs (sea lizards with a very long neck, making up more than half of the body and reaching a length of 13-14 m);
6th direction - ichthyosaurs (lizard fish). Appearance similar to fish and whale, short neck, fins, swim with the help of the tail, legs control the movement. Intrauterine development - live birth of offspring.
At the end of the Cretaceous period, during the formation of the Alps, climate change led to the death of many reptiles. During the excavations, the remains of a bird the size of a dove, with the teeth of a lizard, which had lost the ability to fly, were discovered.
Aromorphoses that contributed to the appearance of mammals.
1. The complication of the nervous system, the development of the cerebral cortex had an impact on the change in the behavior of animals, adaptation to the living environment.
2. The spine is divided into vertebrae, the limbs are located from the abdominal part closer to the back.
3. For intrauterine bearing of cubs, the female has developed a special organ. The babies were fed with milk.
4. Hair appeared to preserve body heat.
5. There was a division into a large and small circle of blood circulation, warm-bloodedness appeared.
6. Lungs have developed with numerous bubbles that enhance gas exchange.
1. Periods of the Mesozoic era. Triassic. Yura. Bor. Tricodonts. Dinosaurs. Archosaurs. Plesiosaurs. Ichthyosaurs. Archeopteryx.
2. Aromorphoses of the Mesozoic.
1. What plants were widespread in the Mesozoic? Explain the main reasons.
2. Tell us about the animals that developed in the Triassic.
1. Why is the Jurassic period called the period of the dinosaurs?
2. Disassemble the aromorphosis, which is the cause of the appearance of mammals.
1. In what period of the Mesozoic did the first mammals appear? Why weren't they widespread?
2. Name the types of plants and animals that developed in the Cretaceous period.
In what period of the Mesozoic did these plants and animals develop? Opposite the corresponding plants and animals, put the capital letter of the period (T - Triassic, Yu - Jurassic, M - Cretaceous).
1. Angiosperms.
2. Tricodonts.
4. Eucalyptus.
5. Archeopteryx.
6. Turtles.
7. Butterflies.
8 Brachiosaurs
9. Tuataria.
11. Dinosaurs.
The class Reptiles (reptiles) includes about 9,000 living species, which are divided into four orders: Scaly, Crocodiles, Turtles, Beakheads. The latter is represented by only one relic species - tuatara. The scaly ones include lizards (including chameleons) and snakes.
The quick lizard is often found in central RussiaGeneral characteristics of reptiles
Reptiles are considered the first true land animals, since they are not connected in their development with the aquatic environment. If they live in water aquatic turtles, crocodiles), they breathe with lungs and come to land for reproduction.
Reptiles are settled on land much more than amphibians, occupying more diverse ecological niches. However, due to being cold-blooded, they predominate in warm climates. However, they can live in dry places.
Reptiles evolved from stegocephalians (an extinct group of amphibians) at the end of the Carboniferous period of the Paleozoic era. Turtles appeared earlier, and snakes later than all.
The heyday of reptiles fell on the Mesozoic era. During this time, various dinosaurs lived on Earth. Among them were not only terrestrial and aquatic species, but also flying ones. Dinosaurs became extinct at the end of the Cretaceous.
Unlike amphibians, reptiles
improved head mobility due to a larger number of cervical vertebrae and a different principle of their connection with the skull;
the skin is covered with horny scales that protect the body from drying out;
breathing only lung; the chest is formed, which provides a more perfect breathing mechanism;
although the heart remains three-chambered, the venous and arterial circulations are better separated than in amphibians;
pelvic kidneys appear as organs of excretion (and not trunk ones, as in amphibians); such kidneys better retain water in the body;
the cerebellum is larger than that of amphibians; increased volume of the forebrain; the rudiment of the cerebral cortex appears;
internal fertilization; reptiles reproduce on land mainly by laying eggs (some are viviparous or ovoviviparous);
germinal membranes appear (amnion and allantois).
Reptile skin
The skin of reptiles consists of a multi-layered epidermis and a connective tissue dermis. The upper layers of the epidermis become keratinized, forming scales and scutes. The main purpose of the scales is to protect the body from water loss. In total, the skin is thicker than that of amphibians.
Reptile scales are not homologous to fish scales. Horny scales are formed by the epidermis, that is, it is of ectodermal origin. In fish, scales are formed by the dermis, i.e., are of mesodermal origin.
Unlike amphibians, there are no mucous glands in the skin of reptiles, so their skin is dry. There are only a few odorous glands.
In turtles, a bony shell forms on the surface of the body (above and below).
Claws appear on the fingers.
Since keratinized skin inhibits growth, molting is characteristic of reptiles. At the same time, the old covers move away from the body.
The skin of reptiles fuses tightly with the body, without forming lymphatic sacs, as in amphibians.
reptile skeleton
In comparison with amphibians, in reptiles, not four, but five departments are distinguished in the spine, since trunk region subdivided into thoracic and lumbar.
In lizards, the cervical region consists of eight vertebrae (in different species there are from 7 to 10). The first cervical vertebra(atlas) looks like a ring. The odontoid process of the second cervical vertebra (epistrophy) enters it. As a result, the first vertebra can rotate relatively freely around the process of the second vertebra. This gives more head movement. In addition, the first cervical vertebra is connected to the skull with one mouse, and not two as in amphibians.
All thoracic and lumbar vertebrae have ribs. In lizards, the ribs of the first five vertebrae are attached by cartilage to the sternum. The chest is formed. The ribs of the posterior thoracic and lumbar vertebrae are not connected to the sternum. However, snakes do not have a sternum, and therefore do not form chest. This structure is associated with the peculiarities of their movement.
The sacral spine in reptiles consists of two vertebrae (and not one as in amphibians). The iliac bones of the pelvic girdle are attached to them.
In turtles, the vertebrae of the body are fused with the dorsal shield of the shell.
The position of the limbs relative to the body is on the sides. In snakes and legless lizards, the limbs are reduced.
Digestive system of reptiles
The digestive system of reptiles is similar to that of amphibians.
In the oral cavity there is a movable muscular tongue, in many species forked at the end. Reptiles are able to throw it far.
Herbivorous species have a caecum. However, most are predators. For example, lizards eat insects.
The salivary glands contain enzymes.
Respiratory system of reptiles
Reptiles breathe only with the lungs, because due to keratinization, the skin cannot take part in breathing.
The lungs are being improved, their walls form numerous partitions. This structure increases the inner surface of the lungs. The trachea is long, at the end it divides into two bronchi. In reptiles, the bronchi in the lungs do not branch.
Snakes have only one lung (the right one, while the left one is reduced).
The mechanism of inhalation and exhalation in reptiles is fundamentally different from that of amphibians. Inhalation occurs when the chest expands due to stretching of the intercostal and abdominal muscles. At the same time, air is sucked into the lungs. When exhaling, the muscles contract and the air is pushed out of the lungs.
The circulatory system of reptiles
The heart of the vast majority of reptiles remains three-chambered (two atria, one ventricle), and arterial and venous blood is still partially mixed. But in comparison with amphibians, in reptiles, the venous and arterial blood flows are better separated, and, consequently, the blood mixes less. There is an incomplete septum in the ventricle of the heart.
Reptiles (like amphibians and fish) remain cold-blooded animals.
In crocodiles, the ventricle of the heart has a complete septum, and thus two ventricles are formed (its heart becomes four-chambered). However, blood can still mix through the aortic arches.
From the ventricle of the heart of reptiles, three vessels independently depart:
From the right (venous) part of the ventricle common trunk of the pulmonary arteries, which further divides into two pulmonary arteries, going to the lungs, where the blood is enriched with oxygen and returned through the pulmonary veins to the left atrium.
Two aortic arches depart from the left (arterial) part of the ventricle. One aortic arch begins to the left (however called right aortic arch, as it bends to the right) and carries almost pure arterial blood. From the right aortic arch originate the carotid arteries going to the head, as well as the vessels supplying blood to the girdle of the forelimbs. Thus, these parts of the body are supplied with almost pure arterial blood.
The second aortic arch departs not so much from the left side of the ventricle as from its middle, where the blood is mixed. This arch is located to the right of the right aortic arch, but is called left aortic arch, as it bends to the left at the exit. Both aortic arches (right and left) on the dorsal side are connected to a single dorsal aorta, the branches of which supply the organs of the body with mixed blood. The venous blood flowing from the organs of the body enters the right atrium.
excretory system of reptiles
In reptiles, in the process of embryonic development, the trunk kidneys are replaced by pelvic ones. The pelvic kidneys have long tubules of nephrons. Their cells are differentiated. In the tubules, water is reabsorbed (up to 95%).
The main excretory product of reptiles is uric acid. It is almost insoluble in water, so the urine is mushy.
The ureters depart from the kidneys, flowing into the bladder, which opens into the cloaca. In crocodiles and snakes, the bladder is underdeveloped.
Nervous system and sense organs of reptiles
The brain of reptiles is being improved. In the forebrain, the cerebral cortex appears from the gray medulla.
In a number of species, the diencephalon forms a parietal organ (third eye), which is able to perceive light.
The cerebellum in reptiles is better developed than in amphibians. This is due to the more diverse motor activity of reptiles.
Conditioned reflexes are developed with difficulty. The basis of behavior is instincts (complexes of unconditioned reflexes).
The eyes are equipped with eyelids. There is a third eyelid - the nictitating membrane. In snakes, the eyelids are transparent and grow together.
A number of snakes at the front end of the head have pits that perceive thermal radiation. They well determine the difference between the temperatures of surrounding objects.
The organ of hearing forms the inner and middle ear.
The sense of smell is well developed. In the oral cavity there is a special organ that distinguishes odors. Therefore, many reptiles stick out a forked tongue at the end, taking air samples.
Reproduction and development of reptiles
All reptiles are characterized by internal fertilization.
Most lay their eggs in the ground. There is a so-called ovoviviparity, when the eggs linger in the genital tract of the female, and when they leave them, the cubs immediately hatch. At sea snakes real live birth is observed, while the embryos form a placenta similar to the placenta of mammals.
Development is direct, a young animal appears, similar in structure to an adult (but with an underdeveloped reproductive system). This is due to the presence of a large supply of nutrients in the yolk of the egg.
In the egg of reptiles, two embryonic shells are formed, which are not found in the eggs of amphibians. it amnion and allantois. The embryo is surrounded by an amnion filled with amniotic fluid. Allantois is formed as an outgrowth of the posterior end of the intestine of the embryo and performs the functions of the bladder and respiratory organ. The outer wall of the allantois is adjacent to the shell of the egg and contains capillaries through which gas exchange takes place.
Caring for offspring in reptiles is rare, it consists mainly in protecting the masonry.
The next after the Permian - the Triassic period opens a new era of the life of the Earth - the Mesozoic, (more details:). This era is characterized as era of ancient reptile giants. The era of ancient reptile giants. Ancient Mastodoisaurus (chest lizard).
Flora and fauna of the Triassic period
As well as in the Permian period, the land in the Triassic prevails over the sea. The climate continues to be continental, dry, but warm enough. Deserts are widely spread. AT vegetable the cover is dominated by gymnosperms, especially cycads, conifers and gingos, as well as seed ferns, which were already common in the Permian period (more details:).Inhabitants of reservoirs
AT reservoirs In the Triassic, ammonites, striking in their abundance and variety of forms, as well as belemnites, were widely developed. In the Triassic, the first bony fish. Now this group includes, according to the definition of specialist scientists, nine-tenths of all fish species.land dwellers
On the land amphibians were still widespread. Some of them reached enormous sizes. In a three-meter, for example, a representative of the stegocephalic group, in Mastodoisaurus, the massive skull alone accounted for more than a meter. The heavy, clumsy body of the lizard, ending in a short thick tail, rested on limbs, obviously not adapted for movement on the ground. The eyes, judging by the position of the eye sockets, looked up, like those of a crocodile. From this we can only conclude that this huge monster lived in the aquatic environment, and got out on land, relying mainly on its wide chest, which is noted in the name of the animal: in Greek “mastos” - chest, “sauros” - lizard , lizard, but in general - "breast lizard".Sea dwellers
New groups of reptiles appear in large numbers in the Triassic - crocodiles, turtles and lizards. Some of them moved to sea where they proved to be fearsome predators. Judging by the features of the structure, the exceptional adaptability to the aquatic lifestyle was distinguished by ichthyosaur(translated from the ancient Greek language - "fish lizard"), reaching 13 meters in length.
Marine predator - fish lizard - ichthyosaur (imprint in the rock). This terrible marine predator combined some signs of a fish (tail and spine), a whale (fins), a dolphin (muzzle) and a crocodile (teeth). Among the ichthyosaurs, apparently, there were also viviparous forms, which is confirmed by the findings of the bones of the young inside the maternal skeletons. A little later, another, no less terrible predator appeared - plesiosaur, up to 15 meters long. Translated from ancient Greek - "resembling a lizard": from the word "plesios" - close, related. 
Ancient plesiosaur. By appearance he represented, as it were, a combination of a turtle with a snake: the turtle-like body of a plesiosaur with powerful flippers ended on one side with a long tail, and on the other, with a snake's neck with a small toothy head. Indeed, as if a snake was pulled through a huge sea turtle, some plesiosaurs had up to 40 large cervical vertebrae. The ichthyosaurs and plesiosaurs reached their greatest prosperity in the next Jurassic period. Land representatives of reptiles were also of enormous size. Mammal development
Since the end of the Triassic, finds of alleged ancestors have been known mammals. These are still very primitive animals, close to the animal-toothed reptiles and to marsupial mammals, which are now preserved only in Australia and South America. These animals were still small, the size of a rat, and very few in number. The path of development of Permian animal-like lizards at the end of the Paleozoic, led in the Triassic to the formation of a new class of vertebrates - mammals. Having passed through the entire Mesozoic, this class develops magnificently only in the next, Cenozoic era. Just as the Mesozoic is called the kingdom of reptiles, in the same way the Cenozoic becomes the kingdom of mammals. The remains of the first mammals, however, are extremely scarce: in most cases these are individual teeth or jaws, however, interesting conclusions can be drawn from these seemingly insignificant remains. Indeed, in reptiles, such as crocodiles, teeth have their own characteristic shape, in mammals (cow, dog, man) - another. By the teeth, you can determine what kind of food the animal ate - vegetable or meat, that is, whether it was a herbivore or a carnivore. According to the structure of the teeth and jaws of the most ancient alleged ancestor of mammals, it can be established that this nondescript, sharp-faced animal was a predator and at the same time insectivorous. Thus, his peers - reptiles were, as they say, not only beyond his strength, but also too tough.Jurassic nature
In the Jurassic period following the Triassic, the strong dissection of the continents by inland seas and the flat relief provided the necessary conditions for the establishment of a humid, even and warm climate, which determined the development of lush vegetation not only in the seas, but even on,.Plant world of the Jurassic period
The flora of the Jurassic generally differs slightly from the Triassic. In the landscape of the Jurassic forest, there are well-known representatives: under the canopy of tall coniferous trees, there are continuous impenetrable thickets of cycads and ferns. Among conifers, it should be noted the gigantic sequoia and the characteristic araucaria with large scaly leaves. Sequoia, otherwise the mammoth tree, or wellingtonia, has survived only on the western slopes of the Sierra Nevada (USA) at an altitude of up to 2000 meters. Individual trees reach 120 meters in height with a diameter of 15 meters. It is believed that the age of these giants flora 6-7 thousand years.
Mammoth tree (sequoia) in California. Araucaria is found in South America and Australia. Araucaria wood is of high technical quality; the seeds of most species are edible, and the fruit cone is sometimes the size of a human head. Sequoias and araucaria grow in the park culture of the Black Sea subtropics (Sochi - Arboretum Botanical Garden). Sea waters of the Jurassic period
In sea waters jurassic the rapid flowering of belemnites, ammonites and corals continues; bony fish are still not widely distributed in either freshwater or marine waters.
Giant herbivorous and carnivorous dinosaurs
Reptiles continue their development. They are widely distributed on land, in water and in the air. Among terrestrial reptiles, first of all, attention is drawn to giant herbivorous and predatory dinosaurs (translated from ancient Greek as “terrible lizards”), which exceeded in size the largest land animals known to us. Among herbivorous dinosaurs, a prominent place was occupied by brontosaurus, otherwise - "thunder lizard" (from the Greek word "bonte" - thunder), 20 meters in length; weighed at least 30 tons.
Herbivorous "thunder lizard" brontosaurus. Diplodocus in translation from ancient Greek - "dvudum". This definition is explained by the fact that diplodocus had two accumulations of medulla: one was placed in the small head of a giant, the other in the sacral expansion of the spinal canal. Its length reached 26 meters. 
Skeleton of an ancient diplodocus "dvudum". In size, the “hind” brain was much larger than the anterior one, since the diameter of the spinal canal was several times larger than the diameter of the cranium. It turns out that diplodocus, as they say, was stronger in hindsight. The skull of Diplodocus in general, both in appearance and size, was similar to that of a horse, while that of a Brontosaurus was even much smaller. Dinosaurs are so widely distributed during this exceptionally warm, abundant food Mesozoic era that it may well be called the era of the dinosaurs. Another "heavyweight" - brachiosaurus. Translated from the ancient Greek "brachis" - short, but in general - "short lizard". In fact, it was not at all short (20-24 meters), but its tail really seemed “short” compared to other giants, although it still reached several meters. Its neck and front legs were significantly longer than those of other dinosaurs. Judging by the structure of the skeleton, the brachiosaurus led an aquatic lifestyle, adhering to more deep places in the reservoir. 
Ancient brachiosaurus. It was probably not easy for these giant reptiles to carry their overweight carcass on the ground. In water, body weight naturally decreased, and it became easier for the animal to move. It is believed that the Brachiosaurus weighed at least 50 tons, that is, approximately the same as ten to twelve African elephants weigh. Giant lizards led a predominantly aquatic lifestyle. Judging by the structure of the skeleton and the peculiar fit of the long neck, the Brachiosaurus fed not only on floating aquatic vegetation, but also on bottom silt. Fearing predatory dinosaurs, brachiosaurs did not abuse ground walks. Land was even more peculiar stegosaurus(translated from ancient Greek - “comb lizard”; from the word “stege” - roof, comb), 9 meters long. This clumsy animal, larger than an elephant, had a disproportionately small head. In addition to two rows of dorsal ridges made of huge triangular bone plates, the stegosaurus served as a means of self-defense, long and also paired, sharp spikes on the tail. 
Crested lizard - stegosaurus. There were also stegosaurs with one row of dorsal plates. The powerful development of the hind limbs was associated with the presence of medulla in the sacrum. The diameter of the cavity of the sacrum, where this "hind" brain was located, was many times greater than the diameter of the braincase of the skull. These huge herbivores, inactive and helpless on land, completely disappeared at the beginning of the next, Cretaceous period. Reptiles occupied a dominant position in the animal kingdom of the Jura. They conquered not only land and water, but also air. In this new environment for vertebrates, pterosaurs, or winged lizards (from the Greek word "pteron" - a wing feather). They possessed, like birds, hollow bones, facilitating the overall weight of the skeleton. One extreme finger of the forelimb (little finger) was greatly elongated and thickened. On this finger, judging by the well-preserved and clear prints, a skin membrane was strengthened and, obviously, bare, like in bats, the membrane. She stretched along the body to the thigh of the hind limb. 
Winged lizard - pterosaur. The aircraft of the pterosaurs was far from perfect compared to the wing of a bird, since the slightest damage to the skin membrane prevented flight. The flight of pterosaurs was carried out mainly by gliding movements. Judging by the structure of the teeth, pterosaurs were fish-eating animals. The imperfection of the aircraft was the reason for their final disappearance in the Cretaceous period. Among pterosaurs there were tailed and tailless forms. The first included rhamphorhynchus, otherwise "beak noses" (translated from the ancient Greek "ramphos" - beak and "rice" - nose), the size of a chicken, only with a long toothy "nose". The straight tail of Rhamphorhynchus with a horizontal flight membrane at the end, obviously, played the role of an “elevator” in flight and, in addition, helped during takeoff (by blows against the air). The wings of Rhamphorhynchus resembled those of swifts in general. Perhaps their flight was just as swift. Pterodactyls belonged to the tailless pterosaurs, otherwise “fingerwings” (also from the ancient Greek word “dactylos” - finger), the size of a sparrow, it had small teeth only in the front of the “nose”. The earliest ancestors of birds
From flying lizards, as if very close to birds. Indeed, valuable findings about the relationship ancient birds with reptiles gave a wonderful find of perfectly preserved remains of the most ancient ancestors of the bird, discovered in Bavarian lithographic schists. This dense variety of limestone is used in lithography, hence the name stone. How could the birds get into the stone? Obviously, at that ancient time one of the reservoirs dried up. At the bottom of it accumulated a mass of the finest calcareous sediment, in which the oldest birds are stuck. The sediment gradually hardened and, under the thickness of the rocks that covered it, turned into stone. During the development of lithographic slates, imprints of ancient birds were discovered. One was named Archeopteryx, which means “ancient wing” in ancient Greek (from the words: “archaios” - ancient and “pteryx” - wing), the other - archeornis, or - “ancient bird” (from the word “ornis” - bird). In the structure of the skeleton, they had a number of features that bring them closer to reptiles: a toothy skull, a long, like a lizard, a tail of 20 vertebrae, and three-toed forelimbs with claws. These ancient birds were the size of a crow, the body was covered with feathers, and on the tail they were located in pairs on both sides of the vertebrae. According to these signs, a direct connection between the most ancient birds and reptiles is established. However, the origin of birds must still not be from finger-winged (pterodactyls), which flew like bats, but from more ancient lizards, who learned to walk on their hind legs and in which the scales that covered the body turned into feathers. The relationship between scales and feathers can be traced through the stages of feather development in a chicken. Feathers, replacing the scales, covered the entire body of the lizard and, gradually lengthening on the forelimbs in the form of wings, not only facilitated its gliding descents to the ground and flights from tree to tree, but also take-offs. The flight abilities of the ancestors of ancient birds were also improved by lightening the weight of the skeleton itself due to hollow and airy bones. Gradually separating themselves from terrestrial reptiles, small forms of some ornithischian lizards passed to an aerial way of life.Cretaceous nature
AT Cretaceous especially noticeable changes occurred in the development of the plant world.Cretaceous vegetation
Warm and humid climate the Cretaceous period became cooler, which, of course, could not but affect the character vegetation. At the beginning of the period, it still has much in common with the Jurassic, but in connection with the appearance of angiosperms, significant differences are gradually revealed. In the second half of the period, angiosperms begin to push back the gymnosperms and, finally, occupy a dominant position everywhere: conifers, cycads, ginkgos and others give way to true flowering plants. Vegetation takes on features that bring it closer to modern. Palm trees, lilies and various herbaceous monocots appear. Among the dicots, magnolia, laurel, ficus, plane tree are widely used, poplar, and other plants close to modern ones appear. By the end of the period, forests and meadows with a carpet of flowers already resemble pictures of the modern landscape. Some plants, on the contrary, having appeared for a relatively short time, disappear completely, leaving no offspring behind.Animal world of the Cretaceous period
Development fauna of the Cretaceous period had its own specific features. In marine reservoirs, the smallest protozoa are widespread. The calcareous shells of these organisms were deposited in huge masses on the bottom of the sea and then served as the starting material for the subsequent formation of strata of writing chalk. If we examine under a microscope a specially polished thinnest plate of chalk, otherwise a thin section, then with a magnification of 150 times large clusters are clearly visible, as if connected from separate balls, wheels with knitting needles and other forms of rhizomes. In modern marine sediments taken from the bottom of the ocean, under a microscope, the remains of rhizomes in the form of balls - globigerin (in Latin "globe" - a ball) are visible. When dried, the precipitate becomes chalky. This says that:- many protozoa safely exist to this day, without much change over hundreds of millions of years;
- the formation of chalk in the ancient seas proceeded in the same way as in modern marine sediments. In terms of chemical composition, chalk is quite consistent with limestone, (more:) and, just like them, boils if you drop diluted hydrochloric acid or vinegar.
Skeleton of a giant manjurosaurus. The fact that Manchurosaurus had the ability to swim can be judged not only by a powerful tail, but also by the remains of a swimming membrane on the front and, obviously, on the hind limbs. The elongated front part of the spatulate muzzle somewhat resembles the shape of a duck's beak. The front part of the jaw was covered, like in birds, with a horny plate, behind which teeth sat in several rows, like bristles on a brush. The dental apparatus of Manjurosaurus reached a huge figure - about two thousand teeth. By plunging his duck-like nose into the coastal silt, he acted with it, probably in the same way as a duck, and the "tooth grinder" helped well to grind the shells of mollusks. In many places on the globe, geologists have discovered entire cemeteries of dinosaurs. Not only bones were found here, but also footprints of these animals on the once soft ground. Sometimes the prints were up to 1.3 meters long and 80 centimeters across. In one of the coal mines of the state of Colorado (in the USA), footprints of a dinosaur were found in the rock underlying the coal. The distance between the right and left limbs of the animal was about 4.5 meters. From this we can only conclude that the dinosaur that walked with such gigantic steps was not less than 10 meters, since the tyrannosaurus, about 6 meters tall, walked with smaller steps - 2.7 meters. An equally interesting find was discovered in Mongolia. More than 50 skulls of a relatively small dinosaur were found in the sands here. protoceratops and egg nests. They lay in such a position as if they had just been laid by the females. Elongated oval eggs, 12-20 centimeters in size, resembled bird shells in structure. Protoceratops females apparently dug a fairly large hole in the sand, laid their eggs in it and left, leaving the development of their offspring in the care of the sun. In Greek, "protos" is the first, or primary. 
Dinosaur Protoceratops. Thus, Protoceratops is primary, and, consequently, more simply arranged, primitive in comparison with ceratosaurs of later origin. (Ceratosaurus in ancient Greek means “horned lizard”: from the word “keras” - horn.) However, this primary ceratosaurus did not have horns at all, they were obviously replaced by a beak-shaped muzzle during an attack, and a bone collar on the neck served as reliable protection against enemy. Among the descendants of Protoceratops, Triceratops was especially noticeable, otherwise it was three-horned (translated from the ancient Greek “trais” - three). This very clumsy animal was somewhat similar to a rhinoceros, only much larger than it (8 meters in length, of which the skull accounted for over 2 meters). Triceratops had two impressive supraocular horns, each meter, and one nasal - above the beak-shaped muzzle. The back of the head and neck were protected by a huge bone shield - a collar. Solid weapons served the Triceratops more for self-defense than for attack. The Cretaceous period was marked by the appearance of snakes. Of the living reptiles, they are thus the youngest compared to, for example, crocodiles and turtles. The flying lizards were still in the air. Giant forms appear among them - pteranodons. Translated from ancient Greek, “winged toothless” (from the words: “pteron” - wing, “an” - negation, in this case the preposition “without”, and “odus” - tooth). This flying lizard, with a bizarrely backward skull and toothless beak, surpassed in size with its huge wings (up to 8 meters in span) the largest flying animals of all time. Under the wing of a pteranodon, the largest modern bird, the condor eagle, could well hide, and under the canopy of two wings, even a whole trolleybus or bus. Pteranodon is believed by geologists to have been a marine lizard and, when not floating in the air, like an albatross, floated on water. His mouth opened like that of a fish-eating bird, a pelican, and perhaps he had the same pharyngeal pouch. This is how the era of ancient reptile giants is characterized. Modern pelicans are found along the coasts of the Caspian, Aral, Black and Azov seas; oceanic albatrosses - tireless soarers - nest mainly in the southern hemisphere. Birds continue further development, and although they improve the aircraft, they are still represented only by toothy forms. Mammals also do not show noticeable development: among them are small animals, which in the next Cenozoic era will form into the orders that currently exist. Chapter Four
Age of Reptiles
1. Life on the surface of the Earth.
2. Lizards.
3. The first birds.
4. The period of death of species.
5. The appearance of fur and feathers
We know that for many hundreds of thousands of years the earth was dominated by humid and warm conditions in most places. The abundance of shallow pools contributed to the extensive accumulation of plant matter, which eventually became the basis for the formation of coal. True, there were also cold periods, but they were not so long as to destroy the plant world.
Then, after a long era of abundance of primitive plants, for some time on Earth there came a long period of global cooling and extinction of the then prevailing plant forms. Thus ended Volume One in the history of life on our planet.
Without a doubt, the Mesozoic lowlands were covered with huge thickets of tree ferns and club mosses and looked like a jungle. But at that time there was no grass, no sod, and no flowering plants at all, neither large nor small. Vegetation in the Mesozoic as a whole was distinguished by an inexpressive color. Obviously, in the wet season it was green, and in the dry season it was purple and brown. Perhaps she was far from the beauty that distinguishes forests and thickets today. There was none bright colors, nor the picturesque shades of foliage before the onset of leaf fall, because there were no leaves that could fall off yet. And on the hills above the swampy lowlands, a bare rocky world still stretched, not covered by any vegetation, accessible to all the whims of bad weather.
When we talk about coniferous plants in the Mesozoic period, pines and spruces immediately appear before the mind's eye, which now cover the mountain slopes. But in fact, we are talking only about the evergreen vegetation of the marsh lowlands. The mountains remained as open and lifeless as ever. The monotony of the mountain spaces was broken only by the shades of open rocks, the multicolor of various strata, which even now makes, for example, the mountainous landscape of Colorado so unique.
Among the animals that had spread by that time in lowland areas, reptiles came to the fore, which lived there in great numbers and variety. By that time, most of them had turned into exclusively terrestrial animals.
There are certain differences in the anatomical structure between reptiles and amphibians. These differences were noticeable already in the Carboniferous period of the Upper Paleozoic, when amphibians prevailed over all land animals. However, the main thing that matters to us here is that amphibians had to return to the water to spawn and, at an early stage of development, live in water and under water.
Reptiles in their life cycle got rid of the tadpole stage. More precisely, the tadpole in a reptile completes its development before the young individual hatches from the egg.
In the same way, amphibians got rid of their dependence on the aquatic environment. Some of them, however, returned to her - like mammals, hippos or otters. However, this happened in the course of the further development of these organisms as the result of a long and complex process, which there is no need to set out in detail in our Essays.
In the Paleozoic era, as we have already said, life on Earth had not yet gone beyond the swampy lowlands along the flow of rivers, tidal sea lagoons, etc. However, life in the Mesozoic was already able to adapt much better to a less dense air environment and stubbornly moved forward, conquering open plains and climbing the slopes of low mountains. Reflecting on the history of mankind, and especially on its future, it is impossible not to pay special attention to this fact.
The earliest reptiles known to us, like their relatives - amphibians, had the same large belly and not very strong legs. They spent most of their lives apparently crawling in liquid mud, like modern crocodiles. But in the Mesozoic, they already confidently stood and moved on all four legs. Other, no less numerous species of them have learned to balance the body with their tail, standing on their hind legs, like the current kangaroos, so that the forelimbs can grab prey.
The bones of one very remarkable variety of reptiles, which still moved on four legs, are found in abundance in Mesozoic deposits in South Africa and Russia. By a number of features, in particular, by the structure of the jaw and teeth, these remains approach the skeleton of mammals. Because of this resemblance to mammals, this detachment of reptiles was called theriodonts (animal-toothed lizards).
Another detachment of reptiles is represented by crocodiles; another variety of reptiles eventually turned into freshwater and sea turtles. Two groups of reptiles did not leave living representatives - ichthyosaurs and plesiosaurs. These were huge creatures that, like whales, returned to live in the sea. Plesiosaurus, one of the largest waterfowl of that era, sometimes reached a length of thirteen meters - measured from head to tail - and a good half of its length fell on the neck! And ichthyosaurs were huge dolphin-like sea lizards. But the most extensive group of Mesozoic reptiles, which gave the largest number of varieties, were dinosaurs.
Many of them reached absolutely incredible sizes. In this respect, the dinosaurs that lived on land remained unsurpassed, although even now the marine inhabitants - whales - are not inferior to them in size. Some of the dinosaurs were herbivores. They fed on leaves and young shoots of fern-like trees and shrubs, and sometimes, standing on their hind legs and clasping the trunk of a tree with their front legs, they ate its crown. One of these herbivorous dinosaurs, diplodocus, reached a length of twenty-eight meters. And the gigantosaurus, whose skeleton was excavated in 1912 by scientists of a German expedition in East Africa, was even larger - over thirty meters!
It is believed that these lizards moved on four legs, but it is hard to believe that they were able to withstand such a weight while out of the water. Dinosaur bones ended in cartilage, and their joints were not strong enough. It is unlikely that these monsters would feel good if they happened to leave the river or swampy backwater. The giant herbivorous dinosaur had a voluminous lower body and short limbs, which were almost always under water. The head, neck and forelimbs were much lighter. They were probably above water.
Another notable type of dinosaur was the Triceratops, a reptile similar to a hippopotamus, but with a bony outgrowth on its head, like a rhinoceros. In addition, there were predatory dinosaurs that hunted herbivorous relatives. Of all living creatures that have ever lived on earth, the most terrifying was, obviously, the Tyrannosaurus Rex. Individual specimens of these predatory lizards reached fifteen meters in length (from head to tail). Apparently, tyrannosaurs moved like kangaroos, relying on a massive tail and hind legs. Some scientists even suggest that Tyrannosaurus moved by jumping - in this case, it must have had absolutely incredible muscles. A jumping elephant would be much less impressive. Most likely, the tyrannosaurus hunted herbivorous reptiles - the inhabitants of the swamps. Half immersed in liquid swamp mud, he pursued his victim through the channels and lakes of swampy plains, such as the current Norfolk swamps or the Everglades swamps in Florida.
Another lineage of dinosaur-type reptiles was a group of light pangolins that could float in the air by jumping from the top of a tree. Between the fourth finger and the body they formed a membrane similar to a wing bat. With these webbed wings, they could glide from tree to tree, much like flying squirrels do now.
These chiropteran lizards were pterodactyls. They are also often referred to as "flying lizards". In numerous illustrations depicting landscapes mesozoic period, they are shown hovering in the sky above the jungle or throwing themselves from a height at their prey. But on their sternum, unlike the sternum of birds, there was no keel to which muscles strong enough for long flight were attached.
The appearance of pterodactyls must have had a grotesque resemblance to heraldic dragons. In the Mesozoic jungle, they took the place of birds. Despite the outward resemblance to birds, pterodactyls were not birds and were not their ancestors. The wing structure of a pterodactyl is completely different from that of a bird. It was a palm with one elongated finger and a membrane, and the wing of a bird looks like a hand with feathers that come out of its back. Pterodactyls, as far as we know, did not have feathers. The feather is a very specialized skin structure that has evolved over a long period of time.
Much less common at that time were other creatures that actually looked like birds. The very first of them still planned from the trees, and the later ones already knew how to fly, although not much higher than the forest tops. The primary representatives of birds can rightly be classified as reptiles. They became real birds as their skin scales, characteristic of all reptiles, lengthened and became more complicated, eventually turning into real feathers.
Feathers are the distinctive outer covering of birds. The plumage protects its owner from cold and heat better than any other protective cover, with the possible exception of dense fur. At the earliest stage of the existence of birds, this heat-shielding device, a gift from nature itself, helped birds to conquer those habitats that turned out to be inaccessible to pterodactyls, unsuitable for real flight. Birds actively mastered catching sea fish - if they did not start with it - and settled closer to the Northern and south poles, overcoming the temperature limits that stopped the reptiles.
Obviously, the very first were carnivorous aquatic birds that obtained their food by diving for fish. Until now, some of these primitive species can be found among seabirds inhabiting the coasts of the Arctic and Antarctic seas. In these birds, zoologists find rudimentary remnants of teeth in the beak cavity, which have completely disappeared in other species.
The earliest bird known to science, Archeopteryx, was beakless. She had jaws with a row of teeth, like a reptile. Archeopteryx retained three clawed fingers on the leading edge of the wing. The tail of this creature was also unusual. In all modern birds, the tail plumage grows from a short rump, and in Archeopteryx, feathers were located on both sides of the long tail.
It is possible that the first birds did not fly at all, and the ability to fly appeared later. For example, one very early bird, Hesperornis, was completely wingless. But after the appearance of feathers, so light and strong and so comfortable, the appearance of wings was only a matter of time.
The Mesozoic era - The second volume of the book of life - is truly amazing story reptiles that evolved and spread throughout the Earth. But the most amazing thing in this story is yet to come. Until the very last Mesozoic deposits, we see that all those orders of giant reptiles that were discussed are still unmatched among all life on earth. Nothing seems to threaten their further well-being and prosperity. There are no signs, judging by the paleontological finds, that they had any kind of enemy or rival. Then the Chronicle breaks off. We do not know how long this gap lasted. Many pages in the book of life are missing, precisely those pages on which, perhaps, some catastrophic changes in earthly conditions would be reflected. In subsequent layers, we again find the abundance and variety of forms. plant life and land animals.
But there is no trace of the former diversity and power of reptiles. Most of them were wiped off the face of the earth, leaving no offspring. Pterodactyls disappeared completely, plesiosaurs and ichthyosaurs did not remain alive. Few species of lizards have survived, of which the largest are monitor lizards that live in Indonesia.
The sudden end of the era of giant reptiles is, without a doubt, the most global shock in all of earth's history before the appearance of man. It marked the end of a long period of even and warm climatic conditions and the beginning of a new, more severe time, in which winter became colder, and summer - shorter and hotter. mesozoic life- both vegetable and animal - was adapted to warm conditions, and the cold snap that followed turned out to be fatal for her. Now new prospects opened up for those who could withstand the test of cold and temperature extremes.
Not a trace of the former diversity of dinosaurs has been preserved. Only crocodiles, and even sea and freshwater turtles were able to survive and are very few in nature. Judging by the fossils that we find in the deposits of the Cenozoic era, completely new animals are entering the scene instead of dinosaurs. They were very distantly related to the reptiles of the Mesozoic period and, obviously, were not descendants of the previously dominant species. New life begins to rule the world.
Reptiles, on the other hand, not only lacked the fur and feathers necessary for thermoregulation, but the structure of their hearts was not conducive to maintaining a high body temperature in the surrounding cold conditions.
Whatever the cause of the extinction of the Mesozoic reptiles, it led to far-reaching consequences, since these catastrophic changes simultaneously affected marine life. Changes in living conditions and the end of reptiles on land were accompanied simultaneously by the death of ammonites - marine cephalopods that crawled along the bottom of the primary seas. Most of us have some idea of their huge shells, some of which reached a diameter of half a meter or more. Throughout the Mesozoic deposits, we find a huge variety of ammonites, about a hundred different species. And by the end of the Mesozoic, their species diversity increased even more. There were specimens of the most incredible sizes. But when their time came, they filled up the pages of the Fossil Record. They left no direct offspring.
Some people may be of the opinion that the giant reptiles were supplanted by mammals that competed with them and caused their extinction. Mammals, indeed, turned out to be more adapted to the new conditions. However, nothing of the kind can be said about the ammonites, whose place remains unoccupied to this day. They simply disappeared. For reasons unknown to us, the Mesozoic seas were a favorable habitat for them, and for an equally unknown reason, due to some failure in the usual sequence of days and seasons, their existence suddenly ceased. None of the biological genera of ammonites from all their former diversity has survived to our time. There is only one isolated species that closely resembles and is related to ammonites. This is a pearl nautilus. It is noteworthy that it lives in the warm waters of the Indian and Pacific oceans.
As for the mammals, which may have supplanted the less well-adapted reptiles, as is sometimes said, there is not the slightest sign that they actually competed. There is much more reason to believe - judging by the fossil record as it has survived to this day - that at first the giant reptiles, for a reason not yet known, disappeared from the face of the earth. And only then, after a long, difficult time for all life on earth, when the conditions of existence again became easier, the development of mammals went at an active pace, and they were able to populate the remaining unoccupied world.
We do not know anything about what caused the catastrophic change in terrestrial conditions for all living things. Nor do we know what catastrophes and upheavals our entire solar system. We can only guess about it. Perhaps some huge alien from outer space swept past and hit our planet or even collided with it, giving a new direction to the entire course of the development of life on Earth. Similar cosmic bodies are now falling on us. They invade the earth's atmosphere, heat up from friction with it and light up. They are also called shooting stars. Most of these meteorites burn up without residue while still in the air, but some reach the Earth's surface. In our museums there are individual specimens reaching several meters in diameter.
Perhaps one of these messengers of the cosmos was large enough to cause such massive changes.
However, this is already an area of pure conjecture. Let's get back to the facts we have.
Did mammals exist in the Mesozoic era?
There is no doubt about this. But they were small, inconspicuous and, in general, not numerous.
In the very beginning chapter of the Mesozoic volume of the Chronicle, there are already reptiles - theriodonts, which we mentioned. And in the excavations of the late Mesozoic, small jawbones were found, the structure of which leaves no doubt that they belonged to a mammal.
The Mesozoic mammals or bestial reptiles - so far we cannot distinguish this with a great degree of certainty - were apparently inconspicuous small animals, the size of mice or rats. They were rather outcast reptiles than a separate class of animals. It is possible that they were still laying eggs, and their distinctive feature, the fur coat, was only gradually formed.
They lived far from the water, perhaps in inaccessible desert uplands, like modern marmots. There, they were probably protected from the danger of extermination by carnivorous dinosaurs. Some of them walked on four legs, while others walked on their hind legs, using their front paws to climb trees. Their fossil remains are so rare that in all the vast deposits of the Mesozoic era, not a single complete skeleton has yet been found to test these assumptions.
Small theriodonts, these ancient mammals, first developed a fur coat. Fur hairs, like feathers, are elongated and specialized scales. Wool is what most likely became the key to salvation early mammals. Surviving on the very edge of the inhabited world, far from warm lowlands and swamps, in the process of evolution they acquired an external protective cover, inferior in thermal insulation and thermal protection only to feathers and fluff of seabirds. Therefore, mammals, like birds, were able to withstand the conditions of a difficult period between the Mesozoic and Cenozoic, while most of the original reptiles died.
According to all the main signs, the vegetation that disappeared at the end of the Mesozoic era, including the disappeared marine and terrestrial inhabitants, were adapted to uniformly warm seasonal conditions throughout the year, as well as to life in shallow sea water and marshy lowlands. However, their successors, who were able to overcome the boundary of the Cenozoic era and did it precisely thanks to wool and feathers, acquired the ability to withstand temperature extremes, which was not the case with reptiles. And, as a result, much greater opportunities opened up before them than any living creature before them.
The living space of the Lower Paleozoic was reduced to warm water.
The living space of the Upper Paleozoic was also reduced mainly to warm water and moist earth.
The living space of the Mesozoic era, as far as we know, was mainly reduced to water and lowlands in favorable climatic conditions regions. But in each of these periods, organisms appeared that were forced to overcome the existing restrictions and found themselves in a new living space. During periods extreme conditions, which replaced favorable ones, these marginal organisms survived to inherit then an extinct world.
Here, perhaps, is the main thing that can be said about the paleontological Chronicle. Its main content is the process of continuous expansion of living space. Classes, genera and species appear and disappear during epochs, but the living space only becomes wider with each new epoch. And it never stops expanding. Never before has life conquered such expanses as it does today. The present life, the life of man, extends from pole to pole; she rose to such a height where no one was before man, his submarines visited the cold lifeless abysses of the deepest seas. Machines created by man bite into the core of impregnable mountains. And with thoughts and calculations, a person penetrates into the center of the Earth and reaches out to the most distant stars.
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From the book History of Military Art author Delbruck HansPart four. THE ERA OF PEOPLE'S ARMIES.
In the Mesozoic era, glaciers practically disappear, and a stable warm and humid climate dominates the planet for a long time. It was warm even in the modern Arctic. The regions of Siberia and Indochina were characterized by a tropical and subtropical climate. The water temperature in the area where the modern Baltic Sea is located reached 21-28 °C.
There was a paradise on Earth - a paradise for reptiles. Reptiles seized dominance on land in water and in the air. Thousands and thousands of species of bizarre animals inhabited the Earth. The beginning of the Mesozoic era, the era of the dominance of reptiles, is marked by a significant increase in land. The growth of land is accompanied by active volcanic activity. Volcanoes emit a significant amount of carbon dioxide into the atmosphere, which is so necessary for the life of plants. Vegetation covered the entire Earth with a green carpet - giving food to numerous herbivores.
On land, in water and air, fights between predators and herbivores and between predators were constantly taking place. In the struggle, the tools of attack and defense were improved. Improved nervous system. To protect offspring from predators, herbivorous reptiles began to lead a herd lifestyle. Reptiles have learned to take care of their offspring. Animals not only made clutches in a place favorable for egg maturation, but also protected the eggs from predators. For about 200 million years, reptiles dominated land.
This time, of course, was not wasted, millions and millions of experiments were carried out on Earth to create the most perfect structure in the Universe, the human brain.
Why for tens of millions of years, God could not or did not want to make reptiles intelligent?
Probably, the Supreme Intelligence assumed that dinosaurs would be the bearers of intelligence on the planet, but his plans changed because, thanks to experiments, the new kind animals are mammals. I had to get acquainted with the works of scientists in which they traced the trend in the development of dinosaurs, which could lead to the emergence of intelligent life on Earth.
Convinced that the future belongs to mammals, God did not leave the dinosaurs alone, but actively contributed to the liberation of the Earth from now unnecessary animals. Living space was freed up for primates, and ultimately for humans.
The history of the development of primates on Earth is the history of the development of man himself. As for the brontosaurs, that their time to disappear has come and they have become extinct.
Application:
Excerpts from an article by T. Nikolov. “Golden Age of Reptiles.”
“The history of the world of organisms does not know of another group that would have so quickly reached a huge, fantastic diversity, like reptiles. leaving water basins in the late Caminocoal era, they gave rise to various and most incredible creatures - from small, like a turtle, cotylosaurs to huge, like a ship, brachiosaurs. The extensive branching of the pedigree of reptiles ended in the Permian and Triassic periods. Reptiles were characterized by rapid evolutionary changes in body shape and adaptation to the most diverse conditions of existence. The predecessors of the entire class were cotylosaurs - small primitive reptiles. Descendants of cotylosaurs - thecodonts played special role in the evolution of reptiles. Thecodonts give rise to an amazing group of dinosaurs, as well as flying pangolins (pterosaurs) and crocodiles. The origin of birds is also associated with thecodonts. That is why they are, as it were, the main trunk of the reptile tree.
One of the interesting moments was the return to the water of some representatives of reptiles. Aquatic reptiles also changed the way of reproduction, gradually moving to live birth. Ichthyosaurs have adapted best to life in the water. They appeared in the Triassic, dawned in the Jurassic, and completely died out in the Cretaceous, when other reptiles were still widespread. Ichthyosaurs, like sharks and dolphins, had a typical fish body up to 9 meters long.
The largest dinosaurs belong to the group of semi-aquatic lizards - these are brontosaurs, diplodocus and brachiosaurs. Known finds of brachiosaurus skeletons show that the weight of these giants reached 35-45 tons. If these colossi lived in our time, then thanks to their 12-meter neck they could see through a five-story building. Obviously, the load on the skeleton of these giants was close to critical, and therefore they spent part of the time immersed in water. Many of these ancient giants had, in addition to the brain, its branch, located in the pelvic region of the spine, which controls the movement of huge limbs.
The most large predator- Tyrannosaurus, with a body length of up to 15 m and a height of about 6 meters. He was bipedal with a powerful tail and terrible, sharp teeth.”
