The main stages of the development of life on Earth is a message. Development of life on earth. Climatic Changes - Cenozoic Era

Dinosaur skeletons were found throughout the history of mankind, but our ancestors took them for the bones of dragons, griffins and other mythical beings. When scientists first encountered dinosaur remains in 1677, the director of one of the British museums, Robert Rota, determined the pieces of bones as a fragment of the femoral bone of the human giant. The myths about the doped giants developed several hundred years, until scientists have learned to accurately restore fossil remains and determine their age. Science of mineral animals is improving today, applying the latest research methods. Thanks to it, scientists can accurately restore the appearance of amazing creatures that went on the ground millions of years ago.

Exceptionally rich material for the development of evolutionary ideas was given by the science of Paleontology, which studies the history of life on the remains of the organisms, which are preserved in rocks and sediments (see Fig. 1). Paleontology recreated the main chronology of events that occurred mainly in the last 700 million years, when the evolution of life on our planet was particularly intense.

This part of the history of the development of the Earth is usually divided into large intervals called era. Era in turn are divided into smaller intervals - periods. Periods - on era and century. Er names have greek origin. For example, Mesoza - "middle life", Cenozoa - "New Life". For each era, and sometimes even for the period, their features are characterized in the development of animal and plant world ().

The first 1.5 billion years after the formation of our planet of living organisms did not exist on it. This period is called Qatarhai (Greek "below the oldest"). The formation of the earth's surface took place in Qatarhae, the active volcanic and population processes were accomplished. Life originated on the border of Qatarhery and the Archean era. This is evidenced by the findings of traces of the life of microorganisms in rock rocks of 3.5-3.8 billion years.

The Archean Era lasted 900 million years and almost did not leave traces of organic life. The presence of rocks of organic origin: limestone, marble, carbon dioxide indicates existence in the Archean era of bacteria and cyanobacteria, that is, prokaryotic organisms (see Fig. 2). They lived in the seas, but might have come out on land. In Archey, the water is saturated with oxygen, and soil-forming processes occur on land.

Fig. one

Fig. 2.

It was in the Archean Era that there were three major changes in the development of living organisms: the emergence of the sexual process, the emergence of photosynthesis and the appearance of multicellularity ().

The sexual process appeared as a result of the fusion of two identical cells in flagella, which are considered the most ancient single-cells. With the advent of photosynthesis, a single stem of life was divided into two - plants and animals. And molellue led to a further complication of life: the differentiation of tissues, the occurrence of organs and organ systems (see Fig. 3).

Fig. 3.

In the Proterozoic ERU, the duration of 2 billion years is developed by algae - green, brown, red (see Fig. 4), and mushrooms also occur.

Fig. four

The ancestors of multicellular organisms may have been colonial organisms like modern colonial flagellas (see Fig. 5). And the first multicellular organisms were like modern lips and corals (see Fig. 6).

Fig. five

Fig. 6.

The animal world of that period was represented by all types of invertebrate animals (see Fig. 7).

Fig. 7.

It is believed that at the end of the Proterozoic Era, the primary chords appeared, the subtype of undeperitive, the only representative of which in the modern fauna is the lancing board (see Fig. 8).

Fig. eight

Bilateral symmetric animals appear, the senses, nerve components are developing, the behavior of animals is also complicated (see Fig. 9).

Fig. nine

Paleozoic era began 570 million years ago and was characterized by the most important evolutionary events in the history of the development of organic life on Earth (). At the beginning of this era, the formation of a significant part of the land sushi occurred, the formation of the ozone screen was over, which gave the opportunity about 400 million years ago to enter the land to the first plants - rhinofit (see Fig. 10, 11). They, unlike algae, have already conducted, coating and mechanical tissues; Allowing to exist in the ground-air environment. From rhinofitis, then the main groups of higher dispute plants were occurred: plane-shaped, horsages and fern, of which primary forests were formed () (see Fig. 12).

In the coal period there was a major evolutionary ascent in the development of terrestrial vegetation.

Fig. 10

Fig. eleven

Fig. 12

This period was distinguished by a warm, humid climate. On Earth, huge ground forests were formed, consisting of gigantic ferns, tree horsages and planes with a height of 15 to 20 m.

They had a good conductive system, roots, leaves, but their reproduction was still connected with water. During this period, seed ferns have grown, in which seeds developed instead of the dispute (see Fig. 13). The appearance of seed plants was the largest aromorphosis in the history of the development of the Earth, since the reproduction of seed plants no longer depended on the water. The embryo is in the seed and is provided with a reserve of nutrients.

Fig. 13

From the end of the coal period due to the active population process, the wet climate becomes dry everywhere. Tree ferns die out, only their small forms in wet places remain. Seed ferns are also dying out. The forests of the coal period led to the formation of rock coal deposits.

Fig. fourteen

In the development of the animal world in Paleozoa (see Fig. 14), the most important evolutionary events took place. At the beginning of the era, the first vertebrate animals appeared - shell fish. They possess an inner skeleton, which gave them an advantage in motion compared to invertebrate animals. From the shell fish, then the cartilage and bone fish occurred (see Fig. 15). Among the bone fish were excreted cyzer, from which about 300 million years ago, the first terrestrial vertebrates occurred.

Fig. fifteen

The most primitive ground vertebrals are the ancient amphibians - Stoodacefalai, who dwell in the swampy places (see Fig. 16, 17). Steodacephali joined the signs of fish and amphibians ().

Fig. sixteen

Fig. 17.

Animals of this period, like plants, were inhabited in wet places, therefore, sushi deep into the depths and occupy places removed from the reservoirs. Upon the occurrence of arid conditions at the end of the coal period, large amphibians disappear, only small forms in raw places are preserved.

Replacement (see Fig. 18) came to replace the amphibian. More protected and adapted to existence in dry climate conditions on land, all reptiles, unlike amphibians, have skin protected from drying with horny scales. Their reproduction is no longer associated with water, and eggs are protected by dense shells.

Fig. eighteen

The Mesozoic Era began about 230 million years ago. Climatic conditions were favorable for further development Life on our land. On land at that moment, gone plants dominated, but about 140 million years ago, the first coated bridges, or flowering plants () have already arisen.

In the seas, cephalopods of mollusks and bone fish prevailed (see Fig. 19). A giant lizards - dinosaurs, as well as vivaging ichthyosaurs, crocodiles, flying lizards (see Figure 20, 21) dwell on land.

Fig. nineteen

Fig. twenty

Fig. 21.

But the gigantic reptiles relatively quickly extinct. At the beginning of the Mesozoic, about 200 million years ago, first birds occurred from the group of poultom repties (see Fig. 22), and the first mammals (see Fig. 23) from the group of animal reptiles.

Fig. 22.

Fig. 23.

The high level of metabolism, warm-bloodedness, developed brain allowed birds and mammals to take a dominant position on our planet.

The Cenozoic Era began 67 million years ago and continues to the present day. After the Pleogen and Neogen began the third period of the era - Anthropogen, in which we now live with you.

During this era of the sea and the continents were formed in their modern form. In the Pleugar, the coated plants spread throughout the land and in freshwater reservoirs, there were active formation processes, as a result of which the climate became colder. This led to the change of evergreen forests with deciduous forests. In Anthropogen, a modern flora and fauna was finally formed, a man appeared ().

Paleontology

Paleontology is the science studying the history of life development on Earth on the remains preserved in sedimentary rocks, prints and traces of the vital activity of ancient living organisms. Scientific paleontology arose at the end of the 18th century. Her founder consider George Leopold Cuvier (Fig. 24).

Fig. 24.

For more than 200 years of its existence, Paleontology has accumulated a huge material about ancient plants and animals, many of which are completely different modern forms Life.

Paleontologists explore not only the remains of ancient plants and animals, but also fossils, that is, the bodies or fragments of the bodies of ancient living organisms in which organic substances Over time, replaced with mineral salts. Paleoontology also uses paleoecology and paleoclimatology methods in order to recreate living conditions in which ancient organisms existed. Recently, Paleontology has received a new development due to the fact that it has become available methods of computer tomography, digital microscopy, molecular biology. With the help of these discoveries managed to prove that life on our planet is much more older than it seemed earlier.

Geochronology

For convenience of study and description, the entire history of the Earth is divided into certain periods of time. These gaps differ in duration, silo-forming processes, climate, flora and fauna. In the geochronological chronicles, these periods are characterized by various layers of sedimentary rocks with fossil remains preserved in them. The deeper the sedimentary layer, the ancient fossil in it. The largest units of the geological chronicle are the aons. Two Eona is distinguished: cryptose that translated from Greek means "secret life", and plywood - "obvious life." The aons are divided into era. Two era are distinguished in cryptose: Archey and Proteroza. And in plywood - three era: Paleozoa, Mesoza and Cenozoa. The eras in turn are divided into periods that can have smaller units.

The value of photosynthesis in the development of life on earth

The appearance of autotrophic organisms on Earth led to gigantic changes in its development. First, the appearance and vital activity of plants led to the formation of free oxygen in the atmosphere. The presence of free oxygen has changed biochemical processes, which led to the death of many living organisms, for which free oxygen was destructive toxic. But, on the other hand, the presence of free oxygen in the atmosphere allowed living organisms to master the respiratory process, as a result of which a lot more energy accumulates in the form of an ATP molecule. Such an energetically more favorable way of breathing allowed living organisms to later master the land. In addition, under the action of ultraviolet oxygen turned into ozone. Thanks to this process, a protective ozone screen was formed, not passing hard ultraviolet on the ground. This was another reason why living organisms were able to reach land. In addition, the authotrophic themselves have become higher-energy food for heterotrophs. The interaction of autotrophs and heterotrophs, their birth and death led to the most important process of the occurrence of biological cycle of substances. Due to this, the once lifeless shell has become a biosphere in populated by living organisms.

Bibliography

1. Mamontov S.G., Zakharov V.B., Agafonova I.B., Sonin N.I. Biology. Common laws. - M.: Drop, 2009.
2. Book V.V., Kamensky A.A., Kriksunov E.A. Biology. Introduction to general biology and ecology. Tutorial for 9 CL. 3rd ed., Stereotype. - M.: Drop, 2002.
3. Ponomareva I.N., Kornilova O.A., Chernova N.M. Basics of general biology. Grade 9: Tutorial for students 9 CL. general educational institutions / Ed. prof. I.N. Ponomareva. - 2nd ed., Pererab. - M.: Ventana Graf, 2005.

Homework

1. List the sequence of Earth development.
2. What era do we live in?
3. Could our kind of do not take a dominant position on earth?
4. What happened to animals and plants that have arisen in the Mesozoic?

During the long historical development of life on Earth, a great diversity of biological species and systems arose.

1) In which environment the first living creatures on Earth arose? Describe them.

Answer: Formation and development occurred in an aquatic environment, which was like a broth for saturation by organic and inorganic substances.

2) Based on what data the land history is divided into large stages. What other stages them are subdivided?

Answer: The history of land and the development of life on the planet is divided into steps - era. Periods are distinguished in the erases, and in the periods - the epochs.

3) Fill in the table "Development of life on earth".

• Name era	Duration M M M milling years	Animal and vegetable world
  Qatarhey	began about 4500 million years ago	synthesis of the first organic compounds
  Archey	it began approximately 3500 million years ago	photosynthesis, eukaryotic cells, sexual process, multicellularity
  Proterozoa	started 2500 million years ago	bilateral symmetry, three-layerness, system by organizing, rear intestinal and anal hole
  Paleozoic	started 534 million years ago	the appearance of organisms with a mineral skeleton, the differentiation of the body of plants on the fabric, the separation of the body of animals to the departments, the formation of the jaws, the appearance of the belts of finishing the vertebrates. Dismemberment of the body of plants on organs, transformation of fins into ground limbs, the appearance of air respiration organs, internal fertilization, dense egg shells, skin oroging, the formation of seeds, the formation of a pollen tube and seed
  Mesoza	began about 248 million years ago	4 Chamber Heart, complete tendering of arterial and venous blood flow, dairy glands, flower and fetal appearance, uterus formation
  Cenozoa	more than 65 million years ago	intensive development of the cerebral cortex, thinking, strain

4) Why the beginning of the Paleozoic era can be called a key line in the history of life development on earth?

Answer: vertebrates appeared, in fresh waters - sharks and bone fish - two-plating and cyzer fish; Plants, animals and mushrooms went to the land.

5) What were the first organisms who left the water medium and starting their "triumphal march" on land? When and how the soil was formed?

Answer: prokaryotes (bacteria and cyanobacteria) were the first on land. It happened in Archee. With the release of prokaryotic, the process of soil formation began.

6) What features were characteristic of the first habitants of sushi?

Answer: The appearance of the organisms of the night and ancient lifestyle, development rhythms developed, the leaves and branching of shoots developed in plants.

7) Why is the oldest, primitive and high-organized animals in the same habitat at us? The answer is illustrated by examples.

Answer: All organisms are interconnected.

Creationism: Life was created by the Creator - God.

Biogenesis hypothesis: According to this theory, life can only be born out of the living.

Hypothesian Panxermia (Richter, Gelmagolz, S. Arrenius, P. Lazarev): According to this hypothesis, life could arise once or several times in space. On Earth, life appeared as a result of its browse from space.

Hypothesis of eternity of life (V. Predier, V.I. Vernadsky): Life always existed, there are no problems of the origin of life.

Abogenesis theory: Life originated from inanimate matter by self-organizing simple organic compounds.
■ For the Middle Ages, primitive ideas were characterized, allowing the appearance of entire living organisms from an inanimate matter (it was believed that frogs and insects are far away in crude soil, flies - from rotten meat, fish from Sal, etc.).
■ Modern concretization of this theory is the coactervat-nai hypothesis of Oparin - Holdane.

Coaccamental hypothesis Oparin - Holdane: life has arisen abiogenic through three stages:
■ first stage - the occurrence of organic substances from inorganic under the influence of physical factors of the medium that existed on ancient land more than 3.5 billion years ago;
■ second phase - the formation of complex biopolymers (proteins, fats, carbohydrates, nucleic acids, proteinoids) from simple organic compounds in the waters of the primary ocean of the Earth and the formation of coactervates - droplets of a concentrated mixture of various biopolymers. Coacervats did not possess genetic information providing their reproduction and copying, and therefore were not "alive";
■ third stage - the emergence of lipoprotechnic membrane structures and selective metabolism and the formation of probe-beams - the first primitive heterotrophic living organisms capable of self-reproduction; The beginning of biological evolution and natural selection.

The first carriers of genetic information were RNA molecules. They were formed using proteinides that attract certain nucleotides that were combined into RNA chains. Such a RNA carried information on the structure of proteinoids and attracted corresponding amino acids to themselves, which led to the reproduction of accurate copies of proteinoids. Later, the RNA function switched to DNA (DNA more stable RNA and can be copied with greater accuracy), and RNA began to act as an intermediary between DNA and protein. In the process of evolution, the advantages had those probions in which the interaction of proteins and nucleic acids was the clearer.

Spontaneous evolution

Probionts were anaerobic heterotrophic prokaryotami . Food and energy for vital activity They were obtained from organic substances of abiogenic origin due to anaerobic splitting (fermentation, or fermentation). The exhaustion of organic substance reserves strengthened competition and accelerated the evolution of probions.

As a result, the differentiation of probionts occurred. One of them (primitive ancestors of modern bacteria), remaining anaerobic heterotrophs has undergone progressive complication. Other probiions containing certain pigments have acquired the ability to form organic matter by photosynthesis (First, oxygen-free, and then - the ancestors of cyanobacteria - with the release of oxygen). Those. originated anaerobic autotrophic prokaryotes which gradually satuled by free oxygen atmosphere of the Earth.

With oxygen appeared aerobic heterotrophic prokaryotes existing at the expense of more efficient aerobic oxidation of organic substances formed as a result of photosynthesis.

The emergence and evolution of eukaryotes and multicellular organisms

Amoebo-like heterotrophic cells could absorb other small cells. Some of the "eaten" cells did not sit down and turned out to function and inside the host cell. In some cases, such a complex turned out to be biologically mutually beneficial and led to a stable cell symbiosis.

❖ Symbiotic theory appearance (about 1.5 billion, years ago) and the evolution of eukaryotic cells (symbiogenesis):
■ One group of anaerobic heterotrophic probions has entered the symbiosis with aerobic heterotrophic primary bacteria, giving rise to eukaryotic cells having mitochondria as energy organoids;
■ Another group of anaerobic heterotrophic probeondes was united not only with aerobic heterotrophic bacteria, but also with primary photosynthesising cyanobacteriums, giving rise to eukaryotic cells having chloroplasts and mitochondria as energy organoids. Simbionth cells with mitochondria later gave the beginning of the kingdoms of animals and mushrooms; With chloroplasts - the kingdom of plants.

The complication of eukaryot led to cell appearance with polar propertiescapable of mutual attraction and merger, i.e. to the sexual process, diploidity (consequence of this - meyosis), dominance and recession, combinative variability, etc.

❖ Hypothesis appearance of multicellular organisms (2.6 billion, years ago):
■ Gastrea hypothesis (E. Hekkel, 1874): single-cell organisms formed a single-layer spherical colony were the ancestral forms of multicellular. Later at the expense of LPGU ( invagination) The part of the wall of the colony was formed a hypothetical two-layer organism - gastrea, similar to the stage of gastruv of embryonic animal development; At the same time, the cells of the outer layer were performed by coating and motor functions, the cells of the inner layer - the functions of the power and reproduction;

■ Phagotitelle hypothesis (I.I. Mesnikov, 1886; This hypothesis underlies the current ideas about the emergence of multicellular ™): multicellular occurred from unicellular colonial harness organisms. The method of nutrition of such colonies was phagocytosis. Cells who captured prey moved inside the colony, and the fabric was formed - an entoderma that performs the digestive function. Cells remaining outside performed the functions of perception of external irritations, protection and motion; Of them later developed a coating fabric - Ektoderma. Part of the cells specialized in the execution of the reproduction function. Gradually, the colony turned into a primitive, but a holistic multicellular body - phagothella. The confirmation of this hypothesis is now the existing, intermediate between one and multicellular, trichopax organism, the structure of which corresponds to the structure of phagocitella.

The main stages of the evolution of plants

Historical stages

The separation of eukaryotes into several branches from which plants, mushrooms and animals occurred (about 1-1.5 billion, years ago). The first plants were algae, most of which freely swam in the water, the rest were attached to the bottom.

The appearance of the first land plants - rhinofitis (about 500 million years ago, as a result of the process of population and reducing the area of \u200b\u200bthe seas, part of the algae was in small water bodies and on land; some of them died, others adapted, acquiring new signs: they had fabrics that were then formed Differentiated for coating, mechanical and conductive; bacteria, interacting with the minerals of the earth's surface, formed the soil substrate on land). Spore reproduction of rhinofitis.

Extinction of rhinofitis and the appearance of plane, horsages and ferns (about 380-350 million years ago); the emergence of vegetative organs (which increased the effectiveness of the functioning of individual parts of the plants); The appearance of seed fern and coniferous.

The emergence of gone plants (about 275 million years ago), which could dwell in a dry environment; extinction of seed ferns and tree spores; At the highest land plants, the gradual reduction of the haploid generation (Gametophyte) and the predominance of the diploid generation (sporophyte).

The appearance of diatoms algae (about 195 million years ago).

The appearance of coated plants (about 135 million years ago); The flourishing of diatoms algae.

Extinction of many species of plants (about 2.5 million years ago), decay of wood forms, flourishing herbaceous; Acquisition floral world Modern forms.

Biological stages

1. Gaploida transition to diploidity . The diploidity mitigates the effect of adverse recessive mutations for viability and makes it possible to accumulate the reserve of hereditary variability. This transition is traced and when comparing modern plants groups. So, in many algae all cells, except the zygot, haploid. The moss prevails a haploid generation (adult plant) with a relatively weak development of the diploid (the sputum organs). At higher organized brown algae, along with haploid, there are also diploid individuals. But already in ferns, the diploid generation prevails, and in the vicered (pines, ate, etc.) and coated plants (many trees, shrubs, grass) independently exist only diploid individuals (see Fig.).
2. Loss of the communication process of sexual reproduction with water , transition from outdoor fertilization to the internal.
3. Body separation (root, stem, sheet), development of a conductive system, complication of the structure of tissues.
4. Specialization of pollination With the help of insects and the spread of seeds and fruits of animals.

The main stages of the evolution of animals

❖ The most important biological stages of evolution:
■ occurrence of multicellular and increasing dismemberment and differentiation of all organ systems;
■ the occurrence of a solid skeleton (outdoor in arthropods, internal vertebrates);
■ Development of Central nervous system;
■ Development of social behavior in different groups of highly organized animals, which, together with the accumulation of a number of large aromorphosis, led to a person and human society.

The most important aromorphoses and their results

Geochronological scale of land

❖ Qatarhey era (4.7-3.5 billion, years ago): The climate is very hot, strong volcanic activity; Chemical evolution occurs, biopolymers arise.

❖ Archean Era (3.5-2.6 billion, years ago) - the era of the birth of life. Climate hot, active volcanic activity; The emergence of life on Earth, the appearance on the border of the water and ground-air media of the first organisms (anaerobic ge-microchrofs) - probions. The emergence of anaerobic autotrophic organisms, archaebacteria, cyanobacteria; The formation of sediments of graphite, sulfur, manganese, layered limestone as a result of the life of archaebacteria and cyanobacteria. At the end of Archeye - the emergence of colonial algae. The appearance of oxygen in the atmosphere.

❖ Proterozoic era (2.6-0.6 billion, years ago) - ERA early Life; It is divided into early proteodes (2.6-1.65 billion, years ago) and late Proteroza (1.65-0.6 billion, years ago). It is characterized by intensive intensity, multiple cooling and glaciations, active formation of sedimentary rocks, formation in an oxygen atmosphere (at the end of the era - up to 1%), the beginning of the formation of a protective ozone layer in the Earth's atmosphere. In the organic world: the development of single-celled prokaryotic and eukaryotic photosynthesising organisms, the occurrence of the sexual process, the transition from fermentation to breathing (early proteodes); The appearance of lower aquatic plants - stromatolites, green algae, etc. (late proteoda), and by the end of the era - all types of invertebrates of multicellular (except chordovy): sponges, intestinal, worms, mollusks, igblerike, etc.

❖ Paleozoic era (570-230 million years ago) - Era of an ancient life; divided by 6 periods: Cambrian, Ordovik, Silico, Devon, Carbon and Perm.

■ Cambrian (570-490 million years ago): the climate is moderate, Pangea's mainland began to dive into the water of the Ocean Tetis. In the organic world: life is concentrated in the seas; Evolution of multicellular forms; The flourishing of the main groups of algae (green, red, brown, etc.) and marine invertebrate animals with chitinophosphate sink (especially trilobites and archaeauts).

■ Ordor. (490-435 million years ago): The climate is warm, Pangay's immersion reaches a maximum. At the end of the period - exemption from the water of significant territories. In the organic world: abundance and variety of algae; The emergence of corals, marine haggars, semi-ferrous (grapetolites), the first chordovy (frantist fish) and the first land plants - rhinofi-tov. The domination of trilobites.

■ Silicon (435-100 million years ago): the climate is arid and cool; There is a rise of sushi and intensive mining; The concentration of 2 in the atmosphere reaches 2%; The formation of a protective ozone layer is completed. In the organic world: settling sushi by vascular plants (rhinofitis) and the formation of soils on it; the emergence of modern groups of algae and mushrooms; flourishing in the seas of trilobites, grapetolites, corals, cancer; The emergence of maxillary chord (shell and cartilage fish) and the first terrestrial arthropods (scorpions).

■ Devonian (400-345 million years ago): The climate is sharply continental; glaciation, further rise of sushi, full exemption from the sea Siberia and of Eastern Europe; The concentration of 2 in the atmosphere reaches modern (21%). In the organic world: rhinofit flourishing, and then (by the end of the period) their extinction; The emergence of major groups of disputes (mugh-shaped, fernal, plane-shaped, horsages), as well as primitive vote (seed ferns); The flourishing of the ancient invertebrates, and then the extinction of many of their species, as well as the majority of unlimited; The appearance of outstanding insects and spider-shaped; flourishing in the seas of shell, cyzer and two-way fish; Exit to the land of the first four-legged vertebrates (Steodacephalov) - amphibian ancestors.

■ Carbon (coal period) (345-280 million years ago): the climate is hot and wet (in the northern hemisphere), cold and dry (in the southern hemisphere); Lowestly low-albums with extensive swamps, in which the formation of stone coal from the trunks of fernacid. In the organic world: the flourishing of tree-like spores of horsages (calaimates), plane-shaped (lepidodendrones and sigillarium) plants and seed fernnels; The emergence of the first viced (coniferous); The flourishing of the sink ameb (foraminiferator), marine invertebrates, cartilage fish (sharks); The appearance on the land of the first amphibians, the ancient reptiles (quotilosaurs) and winged insects; Mailing of graptolites and shell fish.

■ Permian (280-240 million years ago): dryness increases, there is a cooling, there is intensive intensity. In the organic world: the disappearance of forests from tree fern; the distribution of vote (ginkgy, coniferous); The beginning of the heyday of the Steodacephalov and reptiles; the spread of challenges of mollusks (ammonites) and bony fish; reduction of the number of types of cartilage, cyzer and two-way fish; Mailing trilobites.

❖ Mesozoic era (240-67 million years ago) - Middle Era in the development of life on earth; It is divided into 3 periods: Triass, Yura, chalk.

■ Triassic (240-195 million years ago): climate arid (desert appear); The drift and the separation of continents begins (Mainland Pangea is divided into Lavolasia and Gondwan). In the organic world: extinct seed ferns; the domination of vote (coagovic, ginkgy, coniferous); the development of reptiles; The appearance of charts (Belemnites), the first egg-shaped mammals (triconodonts) and first dinosaurs; The extinction of Steodacephalov and many species of animals that flourished in the Paleozoic Era.

■ Yura (195-135 million years ago): climate arid, continents raised above sea level; On land, a wide variety of landscapes. In the organic world: the appearance of diatoms of algae; the domination of ferns and gone plants; The flourishing of champion and bivalve mollusks, reptiles and giant lizards (ichthyosis, armoredosaurs, diplomovoks, etc.); The appearance of the first toothed birds (archeopteryks); The development of ancient mammals.

■ a piece of chalk (135-67 million years ago): climate wet (many swamps); In many areas, cooling; continuing drift continues; There is an intensive deposition of the chalk (from the shells of Foram Inifer). In the organic world: the dominance of gone plants replacing them with a sharp reduction; The appearance of the first coated plants, their predominance in the second half of the period; the formation of maple, oak, eucalyptus and palm forests; flourishing flying lizards (pterodactyls, etc.); the beginning of the heyday of mammals (sample and placental); By the end of the period, the extinction of giant lizards; bird development; The appearance of higher mammals.

❖ Cenozoic era (It began 67 million years ago and continues to the present) it is divided into 2 periods: Tertiary (Paleogen and Neogen) and quaternary (anthropogen).

■ Tertiary period (from 67 to 2.5 million years ago): climate warm, by the end of the cool; completion of the continent drift; mainland acquire modern outlines; Characteristic intensive intensity (Himalayas, Alps, Andes, Rocky Mountains). In the organic world: The domination of monocycle coated and coniferous plants; the development of steppes; flourishing insects, bivalve and buchetic clams; extinct of many forms of chalp clams; Approach of the species composition of invertebrates to the modern; Wide propagation of bony fish that occupy freshwater reservoirs and sea; divergence and flourishing birds; The development and flourishing of sample and placental mammals similar to modern (cetaceous, hoofs, pebatic, predatory, primates, etc.), in Paleogene - the beginning of the development of anthropoids, in Neogen - the emergence of human ancestors (dripitecs).

■ Quaternary period (anthropogen; 2,5 million years ago) began): sharp cooling climate, giant mainland glaciation (four glacial periods); Formation of modern type landscapes. In the organic world: disappearance as a result of the glaesting of many ancient species of plants, the domination of dietary coated coated; decay of wood and flourishing grassy forms of plants; the development of many groups of marine and freshwater mollusks, corals, igblerike, etc.; extinction of large mammals (mastodont, mammoth, etc.); The appearance, prehistoric and historical development of a person: the intensive development of the cerebral cortex, strain.

Most of the modern scientists believe that the Earth has formed a little earlier than 4.5 billion years ago. Life on it arose relatively quickly. The earliest remnants of extinct microorganisms were found in silica sediments with age 3.8 billion years (see Life and its origin).

The first inhabitants of the Earth were prokaryotes - organisms without a decorated nucleus, similar to modern bacteria. They were anaerobam, that is, they did not use free oxygen for breathing, which was not yet in the atmosphere. The source of food for them was organic compoundsarising from lifeless land as a result of ultraviolet solar radiation, thunderstorms and heat of volcanic eruptions. Another source of energy for them was restored inorganic substances (sulfur, hydrogen sulfide, iron, etc.). Photosyntheses appeared relatively early. The first photosynthesis were also bacteria, but they were used as a source of hydrogen ions (protons) not water, but hydrogen sulfide or organic matter. Life was then represented by a fine bacterial film at the bottom of the reservoirs and in the wet places of sushi. This era of the development of life is called Archean, the oldest (from the Greek word ἀἀχῖῖος - ancient).

At the end of Archey, an important evolutionary event occurred. About 3.2 billion years ago, one of the prokaryotic groups - cyanobacteria produced a modern, oxygenated photosynthesis mechanism with water splitting under the action of light. Forming hydrogen combined with carbon dioxide, and carbohydrates were obtained, and free oxygen came to the atmosphere. The atmosphere of the Earth gradually became oxygen, oxidative. (It is possible that a significant part of oxygen could be released from rocks when the metal core of the Earth was formed.)

All this had important consequences for life. Oxygen in the upper layers of the atmosphere under the action of ultraviolet rays turned into ozone. The ozone screen reliably protected the surface of the earth from cruel solar radiation. It became possible the occurrence of oxygen respiration, energetically more profitable than fermentation, glycolysis, and, consequently, the emergence of larger and more complex arranged eukaryotic cells. There were first unicellular, and then multicellular organisms. Oxygen played and a negative role - all mechanisms for binding atmospheric nitrogen are suppressed by them. Therefore, the atmosphere nitrogen is associated with the bacteria - analyzers and cyanobacteria. The lives of all other organisms on Earth arising later, in the oxygen atmosphere, almost depends on them.

Cyanobacteria Along with the bacteria, they were widespread on the surface of the Earth at the end of Archey and the subsequent era - Proterozoic, the era of primary life (from the Greek words πρότερος - earlier and ζωή - life). Known deposits formed by them - Stromatolites ("carpet stones"). As a source of carbon dioxide, these ancient photosynthesis used soluble calcium bicarbonate. At the same time, insoluble carbonate sunned on a colony of a lime crust. Stromatolites in many areas form whole mountains, but the remains of microorganisms are preserved only in some of them.

Someone later symbionts of some first eukaryotes became cyanobacteria - the ancestors of chloroplasts. The remains of the first undoubted eukaryotes are simple and colonial algae - found in the sediments of the Proterozoic era. They look like Volvoks.

In the next, the Devonian period (from the title name in the UK), which lasted about 60 million years old, a variety of fernist pissed psilifitis, and fish, whose front pair of gill arcs turned into jaws, are frantic. In Devon, there were already basic groups of fish - cartilage, bulk and vopase reader. Some of the latter at the end of Devon came to the land, giving rise to a large group of amphibians.

Cenosis begins with a tertiary period. Early tertiary, or Paleogenic, period includes era: Paleocene, Eocene and Oligocene, which lasted 40 million years. At this time, the living detachments of mammals and birds arose. The newest new life has reached at the beginning of the neogenic period, in the Miocene Epoch, which comes 25 million years ago. Then the first human monkeys appeared. Strong cooling at the end of the next era, Pliocene, led to extinction of thermal-loving flora and fauna on large spaces of Eurasia and North America. About 2 million years ago comes the last period of the history of the Earth - Quaternary. This is the period of the formation of a person, so it is more often called anthropogen.

The main stages of life development on earth

1. What is polymerization?
2. What is general and what is the difference between the processes of glycolysis and breathing?
3. What is the difference eukarot. From prokaryt?

You already know that life before it reached a modern manifold, has passed the long path of evolution.

The hypothesis of Oparin - Holdane was adopted and developed by many scientists. In 1947, English scientist John Bernal formulated hypothesis biopoose. He allocated three main stages of the formation of life: Abiogenous occurrence of organic monomers (chemical), the formation of biological polymers (prebiological) and the emergence of the first organisms (biological) (Fig. 142).

The stage of chemical evolution.

At this stage there was abiogenic synthesis Organic monomers. You already know that the ancient atmosphere of the Earth was saturated with volcanic gases, which included sulfur oxides, nitrogen, ammonia, oxides and carbon dioxides, water pairs and a number of other substances. Active volcanic activities accompanied by emissions large masses Radioactive components, strong and frequent electrical discharges during practically non-terminating thunderstorms, as well as ultraviolet radiation contributed to the formation of organic compounds. An ancient atmosphere did not contain free oxygen, so organic compounds did not oxidized and could accumulate in warm and even boiling waters Different reservoirs are gradually complicated by the structure, forming the so-called "primary broth".

The duration of these processes was many millions and tens of millions of years.

Stage of prebiological evolution.

At this stage, the polymerization reactions were processed, which could be activated with a significant increase in the concentration of the solution (the drying of the reservoir) and even in the humid sand. Ultimately, complex organic compounds were formed by protein-nucleic-lipoid complexes (scientists called them differently: coacervats, hypercycles, probyonds, pregnts, etc.). As a result of prebokiological natural selection The first primitive living organisms appeared, which entered the biological natural selection and gave rise to everything organic world on the ground. Life, obviously, developed in aquatic environment at some depth, as water was the only protection against ultraviolet radiation.

The biological stage of evolution.

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