The Mesozoic era - "The era of middle life", is divided into three periods: Triassic, Jurassic and Cretaceous. The era of middle life (Mesozoic) The era of middle life is called

Triassic

Triassic period ( 250 - 200 million years) (showcases 3, 4; cabinet 22).

The Triassic system (period) (from the Greek "trias" - trinity) was established in 1834 by F. Alberti as a result of the combination of three complexes of layers identified earlier in the sections of Central Europe. In general, the Triassic is a geocratic period: land prevailed over the sea. At that time, there were two supercontinents: Angaria (Laurasia) and Gondwana. The last tectonic movements of the Hercynian folding took place in the Early and Middle Triassic, and the Cimmerian folding began in the Late Triassic. As a result of continued regression, Triassic deposits within the platforms are represented mainly by continental formations: red-colored terrigenous rocks, coals. The seas penetrating into the platform areas from geosynclines were characterized by increased salinity; limestones, dolomites, gypsum, and salts were formed in them. These deposits indicate that the Triassic period was characterized by a warm climate. As a result of volcanic activity, trap formations were formed in Central Siberia and South Africa.

The Triassic period is characterized by typically Mesozoic groups of fauna, although some Paleozoic groups still exist. Among the invertebrates, ceratites predominated, bivalve mollusks were widespread, and six-pointed corals. Reptiles actively developed: ichthyosaurs and plesiosaurs lived in the seas, dinosaurs and the first flying pangolins appeared on land. Gymnosperms were widespread, although ferns and horsetails were still numerous.

The Triassic period includes deposits of coal, oil and gas, diamonds, uranium ores, copper, nickel and cobalt, and small salt deposits.

In the museum's collection you can get acquainted with the collections of fauna from the classical type sections of the Triassic system, located in Germany and Austria. The fauna of the Russian Triassic deposits is represented by collections from Eastern Taimyr, individual exhibits from the North Caucasus, Mount Bogdo and the western sector of the Russian Arctic.

Jurassic period

Jurassic period ( 200 - 145 million years) (showcases 3, 4; cabinets 10, 15, 16, 18).

The Jurassic system (period) was established in 1829 by the French geologist A. Brongniart, the name is associated with the Jura Mountains located in Switzerland and France. In the Jurassic, Cimmerian folding continued, and two supercontinents, Laurasia and Gondwana, existed. This period is characterized by a number of major transgressions. In the seas, mainly limestones and marine terrigenous rocks (clays, clay shales, sandstones) were deposited. Continental deposits are represented by lacustrine-marsh and deltaic facies, often containing coal-bearing strata. In deep-water troughs in geosynclinal areas, strata of effusive rocks and terrigenous deposits were formed, alternating with jaspers. The early Jurassic is characterized by a warm, humid climate; by the late Jurassic, the climate became arid.

The Jurassic period is the heyday of typical Mesozoic groups of fauna. Among invertebrates, cephalopods, ammonites, the most common inhabitants of the sea of ​​that time, are most widely developed. There are numerous bivalve mollusks, belemnites, sponges, sea lilies, six-ray corals. Vertebrate animals are represented primarily by reptiles, the most diverse of which are dinosaurs. Ichthyosaurs and plesiosaurs live in the seas, flying lizards - pterodactyls and rhamphorhynchus - master the airspace. The most common plants jurassic- gymnosperms.

In the Jurassic, large deposits of oil, coal, bauxite, iron ores, manganese, tin, molybdenum, tungsten, gold, silver and polymetals are formed.

The Hall of Historical Geology presents extensive collections of fossil animals from sections typical of the Jurassic system in England, Germany and France. Separate expositions are devoted to the classical areas of Jurassic deposits: the Moscow syneclise, the Ulyanovsk-Saratov trough, the Caspian syneclise, and the Transcaucasus.

Cretaceous period

Cretaceous ( 145-65 million years) (showcases 1, 2; cabinets 9, 12).

The Cretaceous system (period) was identified in 1822 by the Belgian geologist O. d'Allois, the name is associated with deposits of white writing chalk characteristic of these deposits. The Cretaceous period is the time of the end of the Cimmerian folding and the beginning of the next one - the Alpine one. At this time, the disintegration of the supercontinents Laurasia and Gondwana into continental blocks was completed. The Early Cretaceous epoch corresponded to a small regression, and the Late Cretaceous one of the largest transgressions in the history of the Earth. The accumulation of carbonate (including writing chalk) and carbonate-clastic sediments prevailed in the seas. On the continents, terrigenous strata, often coal-bearing, were deposited. For Cretaceous granitoid magmatism is characteristic, and in the Late Cretaceous traps began to erupt in West Africa and on the Deccan Plateau in India.

In the organic world of the Cretaceous, reptiles still predominated among vertebrates; among invertebrates, ammonites, belemnites, bivalves, sea urchins, sea lilies, corals, sponges, and foraminifers remain numerous. In the Early Cretaceous, ferns and various groups of gymnosperms predominated, in the middle of the Early Cretaceous the first angiosperms appeared, and at the end of the period, the largest change in the flora of the Earth took place: flowering plants conquered the dominant position.

Cretaceous rocks are associated with large deposits of oil and natural gas, hard and brown coal, salts, bauxites, sedimentary iron ores, gold, silver, tin, lead, mercury, and phosphorites.

In the museum, the Cretaceous system is represented by expositions dedicated to the Cretaceous of France (where typical sections of divisions and stages of this system are located), England, Germany, Russia (Russian plate, Crimea, Sakhalin, Khatanga depression).

Cenozoic era

Cenozoic era- "The era of new life", is divided into three periods: Paleogene, Neogene and Quaternary.

Paleogene period

Paleogene period ( 65-23 million years) (showcase 2; cabinets 4, 6).

The Paleogene system (period) was identified in 1866 by K. Naumann. The name comes from two Greek words: palaios - ancient and genos - birth, age. Alpine folding continued in the Paleogene. In the Northern Hemisphere there were two continents - Eurasia and North America, in the Southern Hemisphere - Africa, Hindustan and South America, from which Antarctica and Australia separated in the second half of the Paleogene. This period is characterized by an extensive advance of the sea on land, it was the largest transgression in the history of the Earth. At the end of the Paleogene, a regression took place, and the sea left almost all continents. In the seas, strata of terrigenous and carbonate rocks accumulated, among the latter thick strata of nummulite limestone were widespread. In geosynclinal areas, marine sediments also included volcanogenic sequences and flyschoid terrigenous rocks. The sediments of the oceans are mainly represented by foraminiferal or siliceous (radiolarian, diatom) muds. Among the continental sediments, there are terrigenous red-colored strata, lacustrine and marsh deposits, coal-bearing rocks, and peat.

The organic world at the turn of the Cretaceous and Paleogene period has undergone significant changes. The number of reptiles and amphibians sharply decreased, the flowering of mammals began, the most characteristic of which were proboscis (mastodons and dinotheres), rhinoceros (dinocerases, indricotheriums). At this time, toothless birds developed rapidly. Among the invertebrates, foraminifers are especially numerous, primarily nummulitids, radiolarians, sponges, corals, bivalves and gastropods, bryozoans, sea urchins, lower crayfish- ostracods. AT flora angiosperms (flowering) plants dominated, of the gymnosperms only conifers are numerous.

Deposits of brown coal, oil and gas, bituminous shale, phosphorites, manganese, sedimentary iron ores, bauxites, diatomites, potassium salts, amber and other minerals are associated with deposits of the Paleogene age.

In the museum you can get acquainted with the collections of the Paleogene fauna and flora of Germany, the Volga region, the Caucasus, Armenia, Central Asia, Crimea, Ukraine, Aral Sea.

Neogene period

Neogene period ( 23-1.6 million years) (showcase 1-2; cabinet 1, 2)

The Neogene system (period) was identified in 1853 by M. Gernes. During the Neogene period, there was a maximum of Alpine folding and the associated widespread manifestation of orogeny and extensive regression. All the continents have acquired modern outlines. Europe connected with Asia and separated from North America by a deep strait, Africa was fully formed, and the formation of Asia continued. At the site of the modern Bering Strait, the isthmus continued to exist, connecting Asia with North America. Thanks to mountain-building movements, the Alps, the Himalayas, the Cordillera, the Andes, and the Caucasus were formed. Thick strata of sedimentary and volcanic rocks (molasses) were deposited at their foot in troughs. At the end of the Neogene most of continents is freed from the sea. The climate of the Neogene period was rather warm and humid, but at the end of the Pliocene a cooling began, and ice caps formed at the poles. On the continents, lacustrine, marsh, river sediments, coarse clastic red-colored strata, alternating with basalt lavas, accumulated. Weathering crusts formed in places. On the territory of Antarctica there was a cover glacier, and strata of ice- and glacial-marine sediments were formed around. Evaporite deposits (salts, gypsum) are typical for those parts of geosynclinal regions that have undergone uplifts. Coarse and fine clastic rocks, less often carbonates, were deposited in the seas. Silica accumulation belts are expanding in the oceans, volcanic activity is manifested.

Throughout the Neogene general composition fauna and flora is gradually approaching the modern. Bivalves and gastropods continue to dominate in the seas, numerous small foraminifera, corals, bryozoans, echinoderms, sponges, various fish, and whales among mammals. On land, among mammals, carnivores, proboscis and ungulates are the most common. In the second half of the Neogene appear great apes. The most important feature Neogene - the appearance at its very end of representatives of the genus Homo - man. During the Neogene period, tropical and subtropical woody plants are replaced by deciduous, mainly broad-leaved flora.

The Neogene system includes deposits of oil, combustible gases, brown coal, salt (gypsum, rock salt, in some places potassium salts), copper, arsenic, lead, zinc, antimony, molybdenum, tungsten, bismuth, mercury ores, sedimentary iron ores, bauxites.

The Neogene system is represented in the museum by collections of fauna from sections of Austria, Ukraine, and the North Caucasus.

MONOGRAPHIC COLLECTIONS (academic showcases 5, 21, 11, 24, 25)

The Mining Museum houses the richest paleontological monographic collections. They are museum rarities, because. contain new species and genera of fossil fauna and flora of different geological age from different regions of Russia, the description of which is published in monographs and articles. The collections have a special scientific and historical value and are the national treasure of Russia. Collections were collected throughout the 19th and 20th centuries. The beginning of the collection was a fragment of the head shield of a racoscorpion, described by S.S. Kutorgoy in 1838. Currently, the collection includes 138 monographic collections containing more than 6,000 copies by sixty authors. Among them, collections of the most famous geologists and paleontologists of Russia and Europe of the 19th century predominate - I.I. Laguzen, N.P. Barbota de Marni G.P. Gelmersen, E.I. Eichwald and others.

FOSSILIZATION (academic showcase 25).

The objects of paleontology - the science that studies organic world past geological epochs are the fossil remains of extinct organisms, products and traces of their vital activity. The preserved remains of fossil animals are called fossils or fossils (from Latin fossilis - buried, fossil). The process of converting dead organisms into fossils is called fossilization.

The exposition showcases various forms preservation of fossil remains (subfossils, eufossils, ichnofossils and coprofossils).

Subfossils (from Latin sub - almost) are fossils (almost fossils), which have preserved not only the skeleton, but also slightly altered soft tissues. The most famous subfossils are mammoths in permafrost, wood buried in peat bogs.

Eufossils (from Greek eu - real) are represented by whole skeletons or their fragments, as well as imprints and nuclei. Skeletons and their fragments make up the vast majority of fossils and are the main objects of paleontological research. The prints are flattened prints. The most famous are the locations of imprints of fish, jellyfish, worms, arthropods and other animals found in the Jurassic Solengofen shales of Germany and in the Vendian and Cambrian deposits of Australia and Russia. From plants, most often there are imprints of leaves, less often trunks, seeds. Nuclei, unlike imprints, are voluminous formations. They are casts of certain cavities. Among the nuclei, internal and external are distinguished. The inner cores arise due to the filling of the internal cavities of the shells of bivalves, ostracods, gastropods, brachiopods, and ammonites with rock. The cores of plants most often represent the ebb of the core of the trunks. On the inner core there are imprints of various internal structures, and the outer core reflects the features of the shell sculpture. The outer nuclei are ribbed, rough, rough, and the inner ones are smooth, with imprints of muscles, ligaments and other elements of the internal structure.

Ichnofossils (from the Greek ichnos - trace) are represented by traces of the vital activity of fossil organisms. Ichnofossils include traces of movement along the surface of the soil and inside it: traces of crawling and burrowing of arthropods, worms, bivalves; traces of eating, mink, passages and traces of drilling of sponges, bivalves, arthropods; traces of movement of vertebrates.

Coprofossils (from Greek kopros - litter, manure) consist of the waste products of fossil organisms. The waste products of worms and other soil beetles are stored in the form of rollers of various configurations. From vertebrates, coprolites remain - fossil excrement. But the products of vital activity of bacteria and cyanobionts in the form of iron ore (jaspilites) and calcareous layered formations - stromatolites and oncolites seem especially surprising.

FACIES AND PALEOECOLOGY (Showcases 3-6, Academic Displays 5, 11, 24, 25, 21; Cabinets 20, 24) In the center of the hall there is an exposition dedicated to facies types (according to DV Nalivkin's classification) and paleoecology. Here the definition of "facies" is given, and all types of facies are reflected. A facies is a section of the earth's surface with an inherent complex of physical and geographical conditions that determine organic and inorganic processes in this area in given time. The exposition demonstrates marine and continental facies. From marine facies (by the example of samples of various limestones, pebbles, sands, ferro-manganese nodules), one can get acquainted with facies of shallow water, coastal, moderate deep water, bathyal and abyssal. Continental facies are represented by lacustrine, river, glacial, desert and mountain foot facies. The facies of the geological past are determined from rocks and fossils, which contain information about the physical and geographical conditions in which they were deposited, using facies analysis. Facies analysis includes comprehensive studies to determine the facies of the past. The exposition highlights the main methods of facies analysis (biofacies, lithofacies and geological). In the exposition on paleecology - the science of the lifestyle and living conditions of extinct organisms, the samples show the lifestyle of benthic organisms (benthos) and animals living in the water column (plankton and nekton). Benthos is represented by accreting (oysters, crinoids, sea crustaceans - balanus, corals, sponges), elastically attached (bivalves), free-lying (mushroom corals, etc.), burrowing, crawling (trilobites, gastropods, starfish etc.) and drilling (bivalves and sponges - stone borers and wood borers) forms. Plankton are organisms that exist in the water column in suspension. Plankton is represented in the exposition by imprints of jellyfish, graptolites, etc. Organisms that actively move in the water column form nekton. Among its representatives, fish and cephalopods are the most diverse.

GEOLOGY OF THE LENINGRAD REGION (showcase 7, 10; showcases-visors 8, 9; cabinets 33, 40, 47)

Exposure by geological structure this area was created to help students undergoing geological practice in Leningrad region. The Leningrad Region is located in the junction zone of the southern margin of the Baltic Shield and the northwestern part of the Russian Plate. The rocks of the crystalline basement, represented by granites and granite-gneisses, come to the surface in the area of ​​the Baltic Shield and plunge into southbound, overlapping with a sedimentary cover consisting of deposits of the Vendian, Paleozoic and Anthropogenic age. Along the southern coast of the Gulf of Finland there is a steep coastal ledge, called the Baltic-Ladoga Clint, folded carbonate rocks Ordovician. South of the glint is the Ordovician Plateau, on the surface of which there are numerous karst funnels in limestones. South of the Ordovician plateau is located flat surface The main Devonian field, dissected by a dense network of ancient and modern valleys with outcrops of red sandstones of the Middle Devonian. In the eastern part of the Leningrad Region, Upper Devonian, Lower and Middle Carboniferous rocks are exposed. Between the glint and the Karelian Isthmus is the Neva Lowland, formed by alluvial deposits of the Neva, lacustrine deposits of Ladoga and marine transgressions. Baltic Sea. In the relief of the region, glacial forms - kams, ozes, moraine ridges, "ram's foreheads" and "curly rocks" take a wide part. The Leningrad region is rich in minerals that determine the development mining industry. Local raw materials are used by gas-shale (Slantsy), phosphorite (Kingisepp) and aluminum (Volkhov) plants, large cement, alumina, ceramic plants, numerous careers for the extraction of peat, limestone and dolomite, sand and gravel mixtures, foundry sand, glass and bottle raw materials, building bricks. On the coast of Lake Ladoga there is one of the oldest limestone quarries - Putilovsky (the deposit has been developed since the 15th century). The basement floors of many buildings in St. Petersburg are lined with these limestones, the steps of the main staircase leading to the Mining Museum and the Conference Hall are made of blocks of Putilov limestone.

The exposition introduces the rocks and fossil fauna sedimentary cover (Cambrian, Ordovician, Silurian, Devonian, Carboniferous), as well as with the main minerals of the Leningrad region. Here you can see blue Cambrian clays; white quartz sands from the famous Sablinsky caves - ancient adits used for the production of glass and the famous imperial crystal; Ordovician limestones, which were used even in the construction of the first northern Russian fortresses and in the time of Peter the Great in the construction of the capital. Organic remains are represented in the exposition by Ordovician cephalopods with a straight conical shell, brachiopods, trilobites, crinoids, sea bladders and bryozoans, remains of lobe-finned and armored fishes in Devonian red-colored rocks, large brachiopod shells and colonies of corals from carboniferous limestones.

GEOLOGY OF ANTARCTIDA (showcase-canopy 10, cabinet 50)

The exposition reflects the contribution of the scientists of the Mining Institute in the development of Antarctica. Antarctica is the coldest and highest continent. The cold pole of the Earth is located in East Antarctica -89.2 °C. The Antarctic Ice Sheet is the largest ice sheet on the planet, 10 times the size of the Greenland Ice Sheet. Since 1967 St. Petersburg State Mining Institute ( Technical University) participated in all Soviet and Russian Antarctic expeditions and carried out work on drilling deep wells in ice at the Vostok station, located in the center of the Antarctic continent, near the South Magnetic and South Geographic Poles. Employees of the Institute have drilled more than 18,000 meters of wells on the icy continent with the help of their own thermal core barrels. In 1995, in the area of ​​the Vostok station, the 40th Russian Antarctic Expedition discovered a unique relic lake Vostok, according to various estimates, from 500 thousand to a million years old. Institute scientists have developed a methodology and technical means environmentally safe opening of the subglacial Lake Vostok. In the course of a comprehensive study of the ice cover, the phenomenon of ultra-long anabiosis (more than 400 thousand years) in microorganisms was discovered. In ice samples taken from a depth of 3600 m using the USL-3M installation for sterile sampling from ice, living microorganisms were found - three types of thermophilic bacteria that were in ice in a state of anabiosis. These studies experimentally proved the possibility long stay microorganisms in a state of anabiosis with the preservation of their viability when they enter favorable conditions for life. Achievements of scientists of the Mining Institute in drilling deep wells in the ice of Antarctica were awarded gold medals and honorary diplomas, twice entered in the Guinness Book of Records.

The exhibition features fossils, minerals and rocks(magmatic, sedimentary, metamorphic) Antarctica, weathering forms, and water from an ice core recovered from a depth of 3320 m, 400,000 years old.

Palaeozoic.

This era, which began 570 million years ago. years ago, lasted 340 million years. Scientists divide it into six periods. Scientists divide it into six parts.

• 1. The earliest is the Cambrian (lasted 70 million years).
• 2. It was followed by the Ordovician (lasted 60 million years). The first round-mouthed - relatives - appear. They do not yet have jaws, but the structure of the mouth allows them to grab live prey, which is much more profitable than straining silt.
• 3. Silurian (30 million years), the first plants (psilophyte) come to land, covering the shores with a green carpet 25 cm high.
• 4. The next period is the Devonian (60 million years). The land is inhabited by club mosses, ferns, horsetails, mosses. The first insects already live in their thickets.
• 5. The next period is the Carboniferous, or Stone Age (65 million years). In the first vast expanses of land, swampy forests of tree-like ferns, horsetails and club mosses were covered.
• 6. The last period of the era - Perm, or the Permian period (55 million). The climate became cold and drier. wet forests from ferns and club mosses have disappeared.

Era average life(Mesozoic).

The Mesozoic era began 230 million years ago and lasted 163 million years. It is divided into three periods: Triassic (35 million years), Jurassic, or Jurassic period (58 million years), and Cretaceous, or Cretaceous period (70 million years).

In the seas, even in the Permian period, trilobites finally died out. But this was not the sunset of the marine invertebrates. On the contrary: each extinct form was replaced by several new ones. During the Mesozoic era, the Earth's oceans abounded with mollusks: squid-like belemnites (their fossil shells are called "devil's fingers") and ammonites. The shells of some ammonites reached 3m. In diameter. No one else on our planet, either before or later, had such colossal shells!

The Mesozoic, especially the Jurassic, can be called the kingdom of reptiles. But even at the very beginning of the Mesozoic, when the reptiles were just moving towards their dominance, small, furry, warm-blooded mammals appeared next to them. For a long 100 million years they lived next to the dinosaurs, almost invisible against their background, patiently waiting in the wings.

In the Jurassic, dinosaurs also had other warm-blooded rivals - the first birds (Archaeopteryx). They had a lot more in common with reptiles: for example, jaws studded with sharp teeth. In the Cretaceous period, real birds also descended from them.

At the end of the Cretaceous period, the climate on Earth became colder. Nature could no longer feed animals weighing more than ten kilograms. Began mass extinction(stretched, however, for millions of years) dinosaur giants. Now the vacated place could be occupied by animals and birds.

The Mesozoic era began 230 million years ago and lasted 163 million years. It is divided into three periods: the Triassic (35 million years), the Jurassic, or Jurassic period (58 million years), and the Cretaceous, or Cretaceous period (70 million years).

In the seas, even in the Permian period, trilobites finally died out. But this was not the sunset of the marine invertebrates. On the contrary: each extinct form was replaced by several new ones. During the Mesozoic era, the Earth's oceans abounded with molluscs: squid-like belemnites (their fossil shells are called "devil's fingers") and ammonites. The shells of some ammonites reached 3m. In diameter. No one else on our planet, either before or later, had such colossal shells!

In the forests of the Mesozoic, conifers and cypresses, as well as cycads, dominated. We are used to seeing insects hovering over flowers. But such a spectacle became possible only from the middle of the Mesozoic, when the first flower bloomed on Earth. By the Cretaceous period, flowering plants had already begun to crowd out conifers and cycads.

The Mesozoic, especially the Jurassic, can be called the kingdom of reptiles. But even at the very beginning of the Mesozoic, when the reptiles were just moving towards their dominance, small, woolly, warm-blooded mammals appeared next to them. For a long 100 million years, they lived next to the dinosaurs, almost invisible against their background, patiently waiting in the wings.

In the Jurassic, dinosaurs also had other warm-blooded rivals - the first birds (Archaeopteryx). They had a lot more in common with reptiles: for example, jaws studded with sharp teeth. In the Cretaceous period, real birds also descended from them.

At the end of the Cretaceous period, the climate on Earth became colder. Nature could no longer feed animals weighing more than ten kilograms. A mass extinction began (stretching, however, for millions of years) of dinosaur giants. Now the vacated place could be occupied by animals and birds.

The Triassic weakens
climatic zoning, smoothing
temperature differences Start of movement
continents. Gigantic die out
ferns, tree-like horsetails, club mosses.
Gymnosperms are flourishing.
The emergence of the first bony fish. in the triassic
started Great War two land
tribes - reptiles and animal-like.
Phytosaurus

The World of the Early Triassic 250 million years ago, all the land of the Earth was united into the supercontinent Pangea, located in one

The shallow lagoons of the Triassic seas were home to a variety of marine reptiles, including Askeptosaurus (above),

The first mammals evolved from animal-like lizards

Aromorphoses of mammals: (continued)

10. 220 million years ago, the landscape was dominated by shrubs interspersed with coniferous trees resembling modern ones, and huge

11.

12. Ginkgo

13. Oppressive

14. Conifers

15.

16. Asteroceras obtusum - one of the ammonite species that lived in the seas of the Jurassic period. At that time their shells were covered much

17. Development of mammals

18. The middle of the era of dinosaurs (Jurassic period).

19. Allosaurus

20. Stegosaurus

21. Dinosaurs dominated land, water and air

22. One of the largest herbivorous dinosaurs of the Jurassic period - diplodocus (Diplodocus). The long neck allowed him to "comb" food

23. Diplodocus holds an important place in the imagination of many British schoolchildren because of this impressive skeleton displayed in

24. DISCOVERY OF ARCHEOPTERYX

25. The fossilized bones of Archeopteryx (top picture) allowed paleontologists to solve the problem of the appearance of this unusual bird.

26. Aromorphoses of birds

27.

28. This is how the plain of modern Northwestern Europe could look like at the beginning of the Cretaceous period. Dinosaur in the background - herbivore

29. The number and species diversity of mammals increased, animals appeared, the descendants of which are associated primarily with

30. During the transition from the early to the middle Cretaceous, the first flowering plants appeared. At the same time, the evolution

31. Aromorphoses of flowering plants

32. Tyrannosaurus overtaking prey. The largest of the terrestrial predators, it reached 13 m in length and towered 5 m above the ground.

33. By the end of the Cretaceous period, the animal world of the land had reached a great diversity, and its representatives were perfectly adapted to

34. DEATH OF THE DINOSAURS One of the most significant events in the history of the Earth occurred ca. 65 million years ago. Died out at this time

35. conclusion

The origin of life on Earth took place about 3.8 billion years ago, when the formation of the earth's crust ended. Scientists have found that the first living organisms appeared in aquatic environment, and only after a billion years did the first creatures come to the surface of the land.

The formation of terrestrial flora was facilitated by the formation of organs and tissues in plants, the ability to reproduce by spores. Animals also evolved significantly and adapted to life on land: internal fertilization, the ability to lay eggs, and pulmonary respiration appeared. An important stage of development was the formation of the brain, conditioned and unconditioned reflexes, survival instincts. The further evolution of animals provided the basis for the formation of mankind.

The division of the history of the Earth into eras and periods gives an idea of ​​the features of the development of life on the planet in different time periods. Scientists emphasize significant events in the formation of life on Earth in separate periods of time - eras, which are divided into periods.

There are five eras:

• Archean;
• Proterozoic;
• Paleozoic;
• Mesozoic;
• Cenozoic.

The Archean era began about 4.6 billion years ago, when the planet Earth only began to form and there were no signs of life on it. The air contained chlorine, ammonia, hydrogen, the temperature reached 80 °, the radiation level exceeded the permissible limits, under such conditions the origin of life was impossible.

It is believed that about 4 billion years ago our planet collided with a celestial body, and the result was the formation of the Earth's satellite - the Moon. This event became significant in the development of life, stabilized the axis of rotation of the planet, contributed to the purification of water structures. As a result, the first life originated in the depths of the oceans and seas: protozoa, bacteria and cyanobacteria.

The Proterozoic era lasted from about 2.5 billion years to 540 million years ago. Remains of unicellular algae, mollusks, annelids. Soil is starting to form.

The air at the beginning of the era was not yet saturated with oxygen, but in the process of life, the bacteria that inhabit the seas began to release more and more O 2 into the atmosphere. When the amount of oxygen was at a stable level, many creatures took a step in evolution and switched to aerobic respiration.

The Paleozoic era includes six periods.

Cambrian period(530 - 490 million years ago) is characterized by the emergence of representatives of all types of plants and animals. The oceans were inhabited by algae, arthropods, mollusks, and the first chordates (Haikouihthys) appeared. The land remained uninhabited. The temperature remained high.

Ordovician period(490 - 442 million years ago). The first settlements of lichens appeared on land, and the megalograpt (a representative of arthropods) began to come ashore to lay eggs. Vertebrates, corals, sponges continue to develop in the thickness of the ocean.

Silurian(442 - 418 million years ago). Plants come to land, and rudiments of lung tissue form in arthropods. The formation of the bone skeleton in vertebrates is completed, sensory organs appear. Mountain building is underway, different climatic zones are being formed.

Devonian(418 - 353 million years ago). The formation of the first forests, mainly ferns, is characteristic. Bone and cartilaginous organisms appear in water bodies, amphibians began to land on land, new organisms are formed - insects.

Carboniferous period(353 - 290 million years ago). The appearance of amphibians, the sinking of the continents, at the end of the period there was a significant cooling, which led to the extinction of many species.

Permian period(290 - 248 million years ago). The earth is inhabited by reptiles, therapsids appeared - the ancestors of mammals. Hot climate led to the formation of deserts, where only resistant ferns and some conifers could survive.

The Mesozoic era is divided into 3 periods:

Triassic(248 - 200 million years ago). The development of gymnosperms, the appearance of the first mammals. The division of land into continents.

Jurassic period(200 - 140 million years ago). The emergence of angiosperms. The emergence of the ancestors of birds.

Cretaceous period(140 - 65 million years ago). Angiosperms (flowering) became the dominant group of plants. The development of higher mammals, real birds.

The Cenozoic era consists of three periods:

Lower Tertiary period or Paleogene(65 - 24 million years ago). The disappearance of the majority cephalopods, lemurs and primates appear, later parapithecus and dryopithecus. The development of the ancestors of modern mammalian species - rhinos, pigs, rabbits, etc.

Upper Tertiary or Neogene(24 - 2.6 million years ago). Mammals inhabit land, water and air. The emergence of Australopithecus - the first ancestors of humans. During this period, the Alps, the Himalayas, the Andes were formed.

Quaternary or Anthropogene(2.6 million years ago - today). A significant event of the period is the appearance of man, first Neanderthals, and soon Homo sapiens. vegetable and animal world acquired modern features.