On land, the diversity of reptiles increased. Their hind limbs have become more developed than their forelimbs. The ancestors of modern lizards and turtles also appeared in the Triassic period. In the Triassic period, the climate of certain territories was not only dry, but also cold. As a result of the struggle for existence and natural selection, the first mammals appeared from some predatory reptiles, which were not more rats. It is believed that they, like modern platypuses and echidnas, were oviparous.
Plants
Repentant in Jurassic period spread not only on land, but also in water and air environment. Flying lizards have become widespread. The Jurassic also saw the appearance of the very first birds, Archeopteryx. As a result of the flourishing of spore and gymnosperm plants, the body size of herbivorous reptiles increased excessively, some of them reaching a length of 20-25 m.
Plants
Thanks to the warm and humid climate During the Jurassic period, tree-like plants flourished. In the forests, as before, gymnosperms and fern-like plants dominated. Some of them, such as sequoia, have survived to this day. The first flowering plants that appeared in the Jurassic period had a primitive structure and were not widespread.
Climate
IN Cretaceous period The climate has changed dramatically. Cloudiness decreased significantly, and the atmosphere became dry and transparent. As a result Sun rays fell directly on plant leaves. Material from the site
Animals
On land, the reptile class still retained its dominance. Predatory and herbivorous reptiles increased in size. Their bodies were covered with a shell. The birds had teeth, but were otherwise close to modern birds. In the second half of the Cretaceous period, representatives of the subclass of marsupials and placentals appeared.
Plants
Climatic changes in the Cretaceous period had a negative impact on ferns and gymnosperms, and their numbers began to decline. But angiosperms, on the contrary, multiplied. By the mid-Cretaceous, many families of monocotyledonous and dicotyledonous angiosperms had evolved. Due to its diversity and appearance they are in many ways close to modern flora.
Lesson topic:"The Development of Life in the Mesozoic Era"
Duration Mesozoic era approximately 160 million years. The Mesozoic era includes the Triassic (235-185 million years ago), Jurassic (185-135 million years ago) and Cretaceous (135-65 million years ago) periods. The development of organic life on Earth and the evolution of the biosphere continued against the background of paleogeographical changes characteristic of this stage.
The Triassic is characterized by a general rise of platforms and an increase in land area.
By the end of the Triassic, the destruction of most mountain systems that arose in the Paleozoic had ended. The continents turned into huge plains, which were invaded by the ocean in the next, Jurassic, period. The climate became softer and warmer, covering not only tropical and subtropical zone, but also modern temperate latitudes. During the Jurassic period the climate was warm and humid. The increased rainfall caused the formation of seas, huge lakes and large rivers. Changes in physical and geographical conditions affected the development of the organic world. The extinction of representatives of marine and terrestrial biota, which began in the arid Permian, continued, which was called the Permian-Triassic crisis. After this crisis and as a result of it, the flora and fauna of land evolved.
Biologically, the Mesozoic was a time of transition from old, primitive to new, progressive forms. The Mesozoic world was much more diverse than the Paleozoic; the fauna and flora appeared in it in a significantly updated composition.
Flora
The vegetation cover of the land at the beginning of the Triassic period was dominated by ancient conifers and seed ferns (pteridosperms). in arid climates, these gymnosperms gravitated towards moist places. On the coasts of drying reservoirs and in disappearing swamps, the last representatives of ancient club mosses and some groups of ferns perished. By the end of the Triassic, a flora was formed in which ferns, cycads, and ginkgos dominated. Gymnosperms reached a special flourishing during this period.
In the Cretaceous, flowering plants appeared and conquered the land.
The putative ancestor of flowering plants, according to most scientists, was closely related to seed ferns and represented one of the branches of this group of plants. Paleontological remains of primary flowering plants and groups of plants intermediate between them and gymnosperm ancestors are, unfortunately, still unknown to science.
Primary type flowering plant was, according to most botanists, an evergreen tree or low shrub. The herbaceous type of flowering plant appeared later under the influence of limiting environmental factors. The idea of the secondary nature of the herbaceous type of angiosperms was first expressed in 1899 by the Russian botanical geographer A.N. Krasnov and the American anatomist C. Jeffrey.
The evolutionary transformation of woody forms into herbaceous ones occurred as a result of weakening, and then a complete or almost complete decrease in the activity of the cambium. This transformation probably began at the dawn of the development of flowering plants. Over time, it proceeded at a faster pace in the most distant groups of flowering plants and eventually acquired such a wide scale that it covered all the main lines of their development.
Neoteny, the ability to reproduce at an early stage of ontogenesis, was of great importance in the evolution of flowering plants. It is usually associated with limiting environmental factors - low temperature, lack of moisture and a short growing season.
Of the huge variety of woody and herbaceous forms, flowering plants turned out to be the only group of plants capable of forming complex multi-layered communities. The emergence of these communities led to a more complete and intensive use of the natural environment and the successful conquest of new territories, especially unsuitable for gymnosperms.
In the evolution and mass dispersal of flowering plants, the role of pollinating animals is also great. especially insects. By feeding on pollen, insects transferred it from one strobila of the original ancestors of angiosperms to another and were thus the first agents of cross-pollination. Over time, insects have adapted to eat ovules, causing significant harm to plant reproduction. The reaction to such a negative influence of insects was the selection of adaptive forms with closed ovules.
The conquest of land by flowering plants marks one of the decisive, turning-point factors in the evolution of animals. This parallelism in the suddenness and rapidity of the spread of angiosperms and mammals is explained by interdependent processes. The conditions with which the flourishing of angiosperms was associated were also favorable for mammals.
Fauna
Fauna of the seas and oceans: Mesozoic invertebrates were already approaching modern ones in character. A prominent place among them was occupied by cephalopods, to which modern squids and octopuses belong. The Mesozoic representatives of this group included ammonites with a shell twisted into a “ram’s horn”, and belemnites, the inner shell of which was cigar-shaped and overgrown with the flesh of the body - the mantle. Ammonites were found in such numbers in the Mesozoic that their shells are found in almost all marine sediments of this time.
By the end of the Triassic, most of the ancient groups of ammonites died out, but in the Cretaceous they remained numerous, but during the Late Cretaceous the number of species in both groups begins to decline. The diameter of some ammonite shells reaches 2.5 m.
At the end of the Mesozoic, all ammonites became extinct. Of the cephalopods with an external shell, only the genus Nautilus has survived to this day. More widespread in modern seas are forms with internal shells - octopuses, cuttlefish and squids, distantly related to belemnites.
Six-rayed corals began to actively develop(Hexacoralla), whose colonies were active reef-formers. Mesozoic echinoderms were represented by various species of crinoids, or crinoids (Crinoidea), which flourished in the shallow waters of the Jurassic and partly Cretaceous seas. However Sea urchins have made the most progress. They were plentiful sea stars .
Bivalve mollusks have also become widespread.
During the Jurassic period, foraminifera flourished again, survivors Cretaceous period and have survived to modern times. In general, single-celled protozoa were an important component in the formation of Mesozoic sedimentary rocks. The Cretaceous period was also a time of rapid development of new types of sponges and some arthropods, particularly insects and decapods.
The Mesozoic era was a time of unstoppable expansion of vertebrates. Of the Paleozoic fish, only a few transitioned into the Mesozoic. Among them were freshwater sharks, sea sharks continued to develop throughout the Mesozoic; Most modern genera were already represented in the Cretaceous seas, in particular.
Almost all lobe-finned fish, from which the first land vertebrates developed, became extinct in the Mesozoic. Paleontologists believed that lobe-finned animals became extinct by the end of the Cretaceous. But in 1938, an event occurred that attracted the attention of all paleontologists. An individual of a species of fish unknown to science was caught off the South African coast. Scientists who studied this unique fish came to the conclusion that it belongs to the “extinct” group of lobe-finned fish ( Coelacanthida). Until now this view remains the only modern representative of ancient lobe-finned fishes. It got the name Latimeria chalumnae. Such biological phenomena are called “living fossils.”
Sushi fauna: New groups of insects, the first dinosaurs and primitive mammals appeared on land. Reptiles became the most widespread in the Mesozoic, becoming truly the dominant class of this era.
With the advent of dinosaurs in Early reptiles became completely extinct in the mid-Triassic cotylosaurs and beast-like animals, as well as the last large amphibians, stegocephals. Dinosaurs, which represented the most numerous and diverse superorder of reptiles, became the leading Mesozoic group of terrestrial vertebrates starting from the end of the Triassic. For this reason, the Mesozoic is called the era of dinosaurs. In the Jurassic, real monsters could be found among dinosaurs, up to 25-30 m long (including tail) and weighing up to 50 tons. Of these giants, the best known forms are Brontosaurus, Diplodocus and Brachiosaurus.
The original ancestors of dinosaurs may have been the Upper Permian Eosuchians - a primitive order of small reptiles with a lizard-like physique. From them, in all likelihood, a large branch of reptiles arose - archosaurs, which then split into three main branches - dinosaurs, crocodiles and winged lizards. Representatives of archosaurs were thecodonts. Some of them lived in water and looked like crocodiles. Others, similar to large lizards, lived in open areas of land. These land-dwelling thecodonts adapted bipedal walking, which provided them with the ability to observe in search of prey. It was from these thecodonts, which became extinct at the end of the Triassic, that dinosaurs descended, inheriting a bipedal mode of locomotion, although some of them switched to a four-legged mode of locomotion. Representatives of the climbing forms of these animals, which over time moved from jumping to gliding flights, gave rise to pterosaurs (pterodactyls) and birds. Dinosaurs included both herbivores and carnivores.
Towards the end of the Cretaceous, there was a mass extinction of characteristic Mesozoic groups of reptiles, including dinosaurs, ichthyosaurs, plesiosaurs, pterosaurs and mosasaurs.
Representatives of the class of birds (Aves) first appear in Jurassic deposits. The only known first bird was Archeopteryx. The remains of this first bird were found near the Bavarian city of Solnhofen (Germany). During the Cretaceous period, the evolution of birds proceeded at a rapid pace; characteristic of this time, still possessing jagged jaws. The emergence of birds was accompanied by a number of aromorphoses: they acquired a hollow septum between the right and left ventricles of the heart, and lost one of the aortic arches. The complete separation of the arterial and venous blood flows causes birds to be warm-blooded. Everything else, namely the feather cover, wings, horny beak, air sacs and double breathing, as well as shortening of the hindgut, are idioadaptations.
First mammals (Mammalia), modest animals, no larger than a mouse, descended from animal-like reptiles in the Late Triassic. Throughout the Mesozoic they remained few in number and by the end of the era the original genera were largely extinct. Their occurrence is associated with a number of major aromorphoses, developed in representatives of one of the subclasses of reptiles. These aromorphoses include: the formation of hair and a 4-chambered heart, complete separation of arterial and venous blood flows, intrauterine development of the offspring and feeding the baby with milk. Aromorphoses also include development of the cerebral cortex, which determines the predominance of conditioned reflexes over unconditioned ones and the possibility of adaptation to unstable environmental conditions by changing behavior.
Almost all Mesozoic groups of the animal and plant kingdoms retreat, die out, disappear; arises on the ruins of the old new world, the world of the Cenozoic era, in which life receives a new impetus for development and, in the end, living species of organisms are formed.
Eona. The Mesozoic consists of three periods - Cretaceous, Jurassic and Triassic. The Mesozoic era lasted for 186 million years, starting 251 million years ago and ending 66 million years ago. To avoid getting confused about eons, eras and periods, use the geochronological scale, which is located, as a visual clue.
The lower and upper boundaries of the Mesozoic are defined by two mass extinctions. The lower limit is marked by the largest extinction in the history of the Earth - the Permian or Permian-Triassic, when about 90-96% of marine animals and 70% of terrestrial animals disappeared. The upper limit is marked by perhaps the most famous extinction event - the Cretaceous-Paleogene, when all the dinosaurs became extinct.
Periods of the Mesozoic era
1. or Triassic period. Lasted from 251 to 201 million years ago. The Triassic is known for the fact that during this period the mass extinction ends and the gradual restoration of the Earth's fauna begins. Also in the Triassic period, the largest supercontinent in history, Pangea, begins to break apart.
2. or Jurassic period. Lasted from 201 to 145 million years ago. Active development plants, marine and terrestrial animals, giant dinosaurs and mammals.
3. or Cretaceous period. Lasted from 145 to 66 million years ago. The beginning of the Cretaceous period is characterized by the further development of flora and fauna. Large reptile dinosaurs reigned on the earth, some of which reached 20 meters in length and eight meters in height. The mass of some dinosaurs reached fifty tons. The first birds appeared in the Cretaceous period. At the end of the period, the Cretaceous disaster occurred. As a result of this disaster, many species of plants and animals disappeared. The biggest losses were among the dinosaurs. At the end of the period, ALL dinosaurs became extinct, as well as many gymnosperms, many aquatic reptiles, pterosaurs, ammonites, as well as 30 to 50% of all animal species that were able to survive.
Animals of the Mesozoic era
Apatosaurus
Archeopteryx
Askeptosaurus
Brachiosaurus
Diplodocus
Sauropods
Ichthyosaurs
Camarasaurus
Liopleurodon
Mastodonsaurus
Mosasaurs
Nothosaurs
Plesiosaurs
Sclerosaurus
Tarbosaurus
Tyrannosaurus
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Mesozoic era
Mesozoic(Mesozoic era, from Greek μεσο- - “middle” and ζωον - “animal”, “ Living being") - a period of time in the geological history of the Earth from 251 million to 65 million years ago, one of the three eras of the Phanerozoic. First isolated in 1841 by British geologist John Phillips.
The Mesozoic is an era of tectonic, climatic and evolutionary activity. The formation of the main contours of modern continents and mountain building on the periphery of the Pacific, Atlantic and Indian oceans is taking place; the division of land facilitated speciation and other important evolutionary events. The climate was exceptionally warm throughout the entire time period, which also played an important role in the evolution and formation of new animal species. By the end of the era, the bulk of the species diversity of life approached its modern state.
Geological periods
Following Paleozoic era, the Mesozoic extends in time for about 180 million years: from 251 million years ago to the beginning of the Cenozoic era, 65 million years ago. This period is divided into three geological periods, in the following order (beginning - end, million years ago):
- Triassic period (251.0 - 199.6)
- Jurassic period (199.6 - 145.5)
- Cretaceous period (145.5 - 65.5)
The lower (between the Permian and Triassic periods, that is, between the Paleozoic and Mesozoic) boundary is marked by the Permo-Triassic mass extinction, which resulted in the death of approximately 90-96% of marine fauna and 70% of land vertebrates. The upper limit is set at the Cretaceous-Paleocene boundary, when another very large extinction of many groups of plants and animals occurred, most often attributed to the impact of a giant asteroid (Chicxulub crater on the Yucatan Peninsula) and the subsequent “asteroid winter”. Approximately 50% of all species became extinct, including all dinosaurs.
Tectonics
Climate
Warm climate, close to modern tropical
Flora and fauna
Scheme of the evolution of flora and fauna in the Mesozoic era.
Links
Wikimedia Foundation. 2010.
- Mesoamerican writing systems
- Mesokaryotes
See what the “Mesozoic era” is in other dictionaries:
MESOZOIC ERA- (secondary Mesozoic era) in geology, the period of the existence of the globe, corresponding to the deposits of the Triassic, Jurassic and Cretaceous; character. abundance and diversity of reptiles, most of which have become extinct. Dictionary of foreign words included in... ... Dictionary of foreign words of the Russian language
MESOZOIC ERA- MESOZOIC ERATEMA (ERA) (Mesozoic) (from Meso... (see MESO..., MEZ... (part difficult words)) and Greek zoe life), the second erathema (see ERATEMA) (group) of the Phanerozoic eon (see PHANEROZOIC EON) and its corresponding era (see ERA (in geology)) ... ... encyclopedic Dictionary
MESOZOIC ERA- the second geological era after the Precambrian. history of the Earth lasting 160-170 million years. It is divided into 3 periods: Triassic, Jurassic and Cretaceous. Geological Dictionary: in 2 volumes. M.: Nedra. Edited by K. N. Paffengoltz et al. 1978 ... Geological encyclopedia
Mesozoic era- Mesozoic Mesozoic (about the period) (geol.) Topics oil and gas industry Synonyms Mesozoic Mesozoic (about the period) EN Mesozoic ...
Mesozoic era- this is the name in geology for a very significant period in the history of the development of the Earth, which followed the Paleozoic era and preceded the Cenozoic era, to which geologists attribute the period we are experiencing. Deposits of the M. era make up the M. group of layers... Encyclopedic Dictionary F.A. Brockhaus and I.A. Efron
Mesozoic era- (Mesozoic), middle Phanerozoic era. Includes the Triassic, Jurassic and Cretaceous periods. Lasted approx. 185 million years. It began 248 million years ago and ended 65 million years ago. In the Mesozoic, the single huge continents of Gondwana and Laurasia began to split into... Biological encyclopedic dictionary
Mesozoic era- geol. The era in the geological history of the Earth, following the Paleozoic and preceding the Cenozoic (divided into three periods: Triassic, Jurassic and Cretaceous) M ie deposits. M e breeds (of this time) ... Dictionary of many expressions
Mesozoic era- (Mesozoic)Mesozoic, Mesozoic, geological era between the Paleozoic and Cenozoic eras, includes the Triassic, Jurassic and Cretaceous periods, lasted from approximately 248 to 65 million years ago. It was a time of abundance of vegetation and predominance... ... Countries of the world. Dictionary
secondary or Mesozoic era- Mesozoic (geol.) - Topics oil and gas industry Synonyms Mesozoic (geol.) EN Secondary era ... Technical Translator's Guide
Mesozoic era- The era that replaced the Paleozoic in the history of the Earth’s development; began 248 million years ago and preceded the Cenozoic era. It is divided into three periods: Triassic, Jurassic and Cretaceous. [Dictionary of geological terms and concepts. Tomsky... ... Technical Translator's Guide
Books
- Dinosaurs. Complete encyclopedia, Green Tamara. Dinosaurs are interesting to readers of absolutely all ages. This is also a favorite children's theme, as evidenced by numerous cartoons and, of course, the now classic film 'Park...'
Which was followed by . The Mesozoic Era is sometimes called the "Age of the Dinosaurs" because these animals were the dominant species throughout much of the Mesozoic.
After the Permian mass extinction wiped out more than 95% of ocean life and 70% of land species, a new Mesozoic era began about 250 million years ago. It consisted of the following three periods:
Triassic period, or Triassic (252-201 million years ago)
The first big changes were noticed in the type that dominated the Earth. Most of the flora that survived the Permian extinction were seed-bearing plants such as gymnosperms.
Cretaceous period, or Cretaceous (145-66 million years ago)
The last period of the Mesozoic was called the Cretaceous. The growth of flowering land plants occurred. They were helped by newly appeared bees and warm climatic conditions. Conifers were still numerous during the Cretaceous.
In terms of Cretaceous marine animals, sharks and rays became commonplace. Survivors of the Permian extinction, such as starfish, were also abundant during the Cretaceous.
On land, the first small mammals began to develop during the Cretaceous period. First marsupials appeared, and then other mammals. Appeared more birds and there were more reptiles. The dominance of dinosaurs continued, and the number of carnivorous species increased.
At the end of the Cretaceous and Mesozoic, another thing happened. This disappearance is usually called K-T extinction(Cretaceous-Paleogene extinction). It destroyed all dinosaurs except birds and many other life forms on Earth.
Exist different versions as to why the mass extinction occurred. Most scientists agree that there was some kind of catastrophic event that caused this extinction. Various hypotheses include massive volcanic eruptions that released huge amounts of dust into the atmosphere, reducing the amount of sunlight reaching the Earth's surface and thereby causing the death of photosynthetic organisms such as plants and those that depended on them. Others believe that a meteorite fell to Earth and dust blocked the sunlight. Because the plants and animals that fed on them died out, this led to predators such as carnivorous dinosaurs also dying due to lack of food.