Archaean, Proterozoic, Paleozoic, Mesozoic, Cenozoic eras and late biological processes in them
The Archean era lasted 900 million years. His early life left no trace of him. The main reason for this is the change in appearance of sedimentary layers under the influence of high temperature and pressure.
The presence of limestone, marble, and coal materials from organic compounds indicates that there were living organisms, bacteria, and green algae in the Archaic era.
Colonial algae were also found in the later layers of the Archaean. More graphites are found in the rocks of the Archaean. They are a component of organic compounds in microorganisms. Primitive microorganisms created underground resources such as iron, nickel, manganese, sulfur, oil and gas in limestone rocks. In the second half of the Archean era, photosynthesis, sexual reproduction: multicellular organisms appeared.
The Proterozoic Era lasted for 2000 years. At the end of the Archean and the beginning of the Proterozoic, strong mountain formation processes took place. As a result, many dry lands were formed. Bacteria and algae flourished here. In particular, the production of green, blue, and red algae became important. In algae living near the shore, the body is stratified, part of it settles on the substrate - some surface, and the other part adapts to the amalgamation of photosynthesis.
The development of life leads to changes in the shape and order of the Earth's crust. As a result of photosynthetic activity, plants reduced carbon dioxide in the atmosphere and released oxygen. Aerobic organisms appeared as a result of saturation of air and water with oxygen. By the end of the Proterozoic, multicellular organisms such as algae, diatoms, annelids, molluscs, arthropods, and many other types of invertebrates had evolved.
Most of the animals were bilaterally symmetrical. This ensures that their body is divided into anterior and posterior, shoulder and abdominal parts. In the anterior part there are nodes of sense organs. The shoulder of animals provides movement and food storage. All this changes the animal's behavior, mobility, agility, life activity.
It is assumed that by the end of the Proterozoic era, the first chordate animals - a subtype without a head skeleton - appeared. Chorda served as a support for muscles. Later the respiratory organ developed. All of them were the basis for the further improvement of the organic world.
The Paleozoic era lasted 340 million years. This era is characterized by a certain diversity and improvement of life. Since then, the body of eukaryotic organisms has formed a skeleton, allowing the paleontological chronicle to be complete and consistent.
During the Cambrian period, the climate was moderate, and plants and animals were distributed in the sea. Some of them are remote, some are moved by the current of water. Among the animals, bivalves, cephalopods, ringworms, trilobites were widespread and actively moved. The first animal representatives of vertebrates were shield fishes, which did not have jaws. Shields are the ancestors of today's Togarak Ogizli, Mynoga, and Myxina.
In Turkestan, Altai, and Zarafshan mountain ranges, Cambrian animals, clouds, crustaceans, crabs, green and green algae were found. In the Hisar mountain ranges, spores of plants living in mountain land were found.
During the Ordovician period, the level of the seas increased, and the diversity of green, blue, and red algae, cephalopods, and gastropods increased.
Coral reef formation is booming. The diversity of clouds and some bivalve molluscs decreases.
During the Silurian period, mountain formation processes intensified and the land level increased. The climate is relatively dry. Cephalopods are incredibly diggers. By the end of the period, crab scorpions develop. Some of the multicellular green algae scattered in the waters near the coast manage to reach the land due to the struggle for life and natural selection. The soil allowed the spread of early land plant-psilophytes. Accumulation of organic compounds in the soil made it possible for fungi to appear later. Strong volcanic processes took place in Central Asia. The climate was warm. In the Zarafshan mountain ranges, a fossilized image of a low-income psilophyte with cloven-hoofed animals was found.
During the Devonian period, the level of the seas decreased, the land increased, and the separation continued. The climate was moderate. Most of the land has become steppe, semi-steppe. In the seas, bony fishes develop, there was a decrease in fish in the struggle for survival. Bone fish originated from Songra. Bilaterally breathing fishes and clawed fishes have developed in shallow basins. Some species of pinniped fish, Latimeria, live as it is still found in the waters off the coast of Madagascar, South Africa. During this period, the first forests are formed from high-hanging ferns, sedges and plauns. Copepods and early insects appeared due to air-breathing by certain groups of arthropods.
By the middle of the Devonian period, some groups of clawed fishes went on land. As a result, the first types of water and land inhabitants appeared.
At the beginning of the Tashkomir period, a large area of Central Asia was covered with water. At the end of the period, between Amudarya and Syrdarya, on the Aral Sea and on its spherical side, the sea receded and a wide land appeared. Lepidodendrons, plauns, and calamites with high stems hang in abundance among terrestrial spore plants. The height of some calamites reached 20-25 cm. Cordaites, one of the first open-seeded species, were also found there.
During the Tashkomir period, the climate was humid, and the air contained a lot of carbon dioxide. Wetlands are abundant in the dry plains. Ferns, sedges, and sedges up to 40 m in height are hanging on them and covered with spores. In addition to these, open-seeded plants appeared. The complete destruction of woody plants led to the formation of a layer of coal later on. Stegocephalus, which are the first representatives of water and land inhabitants, were extremely numerous and diverse. Flying insects - dragonflies and dragonflies were developed.
By the beginning of the Permian period, the climate was somewhat dry and cold. Such conditions were considered unfavorable for those living in water and on land. Most of them have been destroyed. In the marshes and shallows, many small representatives of water and land dwellers are hiding. Struggle to live in dry and low-temperature conditions, natural selection caused the change of a certain group of people living in water and on land. Then the class of reptiles arose from them.
At the beginning of the Permian period, there were large islands and peninsulas in the Kyzylkum, Fargona and Pamir mountains. Among the plants, calamites, tree-like cordaites, some leafy plants were found.
Thus, during the Paleozoic era, animals developed further and large mammals appeared, i.e., jawless shield fishes, clawed fishes, the first representatives of water and land inhabitants, and finally the class of reptiles appeared. seeds appeared.
LIFE IN THE MESOZOIC AND CENOZOIC ERAS
The Mesozoic era lasted 175 years. The climate became dry during the Triassic period. The forests consisted of open-seeded plants, deciduous plants, sago trees, partially spore-bearing plants, ferns, and ferns. Reptiles have increased on land. Their hind legs are more strongly developed than the front ones. The ancestors of the living lizards and turtles also appeared during this period. During the Triassic period, some areas were dry and cold. As a result, the struggle for survival and natural selection gave rise to early mammals with a rat-like body from some predatory reptiles. It is assumed that they evolved by laying eggs, like modern duckbills, echidnas.
During the Jurassic period, woody plants flourished because the climate was hot and humid. As before, the forests were dominated by angiosperms and ferns. Some of them, the sequoias, have survived to this day. The structure of the first flowering plants that appeared during this period was quite primitive and not widespread. As a result of the rapid development of spore-forming and open-seeded plants, the bodies of equine reptiles have become extremely large. Some of them have a body of 20-25 m. Reptiles are distributed not only on land, but also in water and air. Flying lizards are widespread. Archeopteryx appeared during this period.
During the Cretaceous period, the climate changed dramatically. The clouds covering the sky were greatly reduced, and the atmosphere was dry and clear. The sun's rays began to fall on the leaves of the plant. This change in climate was unfavorable for many ferns and angiosperms, and they declined. Indoor plants, on the other hand, began to sprout. By the middle of the Cretaceous period, many families of monocotyledonous and dicotyledonous classes of angiosperms were developed. Their diversity and appearance are largely close to modern flora. On land, the reptile class still retains some dominance. Carnivorous, equine reptiles have enlarged bodies. Its upper part is protected by shields. The birds were toothed and resembled modern birds in other features. In the second half of the Cretaceous, representatives of the subclass of mammals with marsupials appeared.
The Cenozoic era lasted 70 million years, and the Cenozoic flowering plants, insects, birds, and mammals flourished.
At the beginning of the Tertiary period, the climate was hot and humid. Tropical and subtropical plants are common. In the middle of the period, the climate was temperate, and at the end it cooled sharply. Such changes in the climate led to a decrease in hormones, the emergence and spread of horse plants. The class of insects has evolved rapidly. Among them, high-ranking representatives appeared, which provide external pollination of flowering plants, as well as feed on plant nectar. Reptiles have also declined. On land, in the air, there are birds, mammals, and in the water, there are fish, and for the second time, there are mammals that have adapted to live in the water environment. By the end of the period, many generations of birds that are known today appeared. At the beginning of the period, representatives of the marsupial subclass of mammals became widespread. By the end of the period, they were outmatched in the struggle for survival.
The oldest of the hominids were the insectivores, from which other hominids, including primates, evolved during the Tertiary period.
In the middle of the Tertiary, great apes develop. With the reduction of forests, some great apes are forced to live in open lands. From them later came the first humans. They are few in number and have always struggled to avoid the destructive events of nature and large predators.
During the Cretaceous period, many heat-loving plants spread to the south due to several retreats and retreats of the Arctic Ocean ice, and again to the north with the retreat of the glaciers. Such repeated migration of plants (Latin migratio - migration) caused the mixing of populations, the death of species that could not adapt to the changed conditions, and the emergence of species adapted to the conditions.
By the Cretaceous period, human evolution accelerates. The production of working weapons and their use will improve dramatically. People struggle to survive by changing the environment and organize to create comfortable conditions. The increase in the number of people and their widespread distribution begins to affect the flora and fauna. Due to the early hunters, the number of equine wild animals is gradually decreasing. In Europe and Asia, animals such as mammoths, thick-wooled rhinoceroses, mastodons, horse ancestors, giant sloths, and sea cows were slaughtered by early hunters. The slaughter of large carnivores leads to the slaughter of cave lions, bears and other predators that feed on them. Trees are cut down and many forests are replaced by pastures.
Intermediate forms. Organisms that combine the characteristics of different classes according to their structure are called intermediate forms. The claws and fishes that lived in the Devonian period are an intermediate form between aquatic and land-dwelling creatures. Archeopteryx is an intermediate form between reptiles and birds. Some representatives of theropsids are intermediate forms between reptiles and mammals. Seed ferns are an intermediate form between ferns and gymnosperms. The presence of intermediate forms is also a reliable evidence that the organic world has declined in the historical process.
