Development of life on earth. The main stages of the evolution of flora and fauna. The early stages of the development of life on earth briefly

History of the development of Life on Earth

Paleontology - a science that studies the history of living organisms on Earth, based on preserved remains, prints and other traces of their life activity.

DEVELOPMENT OF LIFE ON EARTH

CRYPTOSOE (hidden life)

About 85% of the total existence of life on Earth

ARCHAY

(ancient)

near

3500 million

(duration about 900 million)

Active volcanic activity. Anaerobic living conditions in a shallow ancient sea. Development of an oxygen-containing atmosphere

The emergence of life on Earth. The era of prokaryotes: bacteria and cyanobacteria. The appearance of the first cells (prokaryotes) - cyanobacteria. The emergence of the process of photosynthesis, the appearance of eukaryotic cells

Aromorphoses: appearance of a formed nucleus, photosynthesis

PROTEROZOIC

(primary life)

about 2600 million (duration about 2000 million)

longest in Earth's history

The surface of the planet is a bare desert, the climate is cold. Active formation of sedimentary rocks. At the end of the era, the oxygen content in the atmosphere is about 1%. Land - a single supercontinent

( Pange I ) The process of soil formation.

The emergence of multicellularity and the process of respiration. All types of invertebrate animals arose. Protozoa, coelenterates, sponges, and worms are widespread. The most common plant species are unicellular algae.

Aromorphoses in animals: the appearance of multicellularity, 2-way symmetry of the body, muscles, body segmentation.

PHANEOZOIC

(explicit life)

PALEOZOIC

(ancient life)

Duration approx. 340 million

Cambrian

OK. 570 million

dl. 80 million

First a moderate humid climate, then a warm dry climate. The land split into continents

The flourishing of marine invertebrates, most of which are trilobites (ancient arthropods), about 60% of all species of marine fauna. The appearance of organisms with a mineralized skeleton. The emergence of multicellular algae

Ordovician

OK. 490 million

dl. 55 million

Moderate humid climate with a gradual increase in temperatures. Temperatures. Intensive mountain building, liberation of large areas from water

The appearance of the first jawless vertebrates (chordates). A variety of cephalopods and gastropods, a variety of algae: green, brown, red. The appearance of coral polyps

Silur

OK. 435 million

dl. 35 million

Intensive mountain building, emergence of coral reefs

Lush development of corals and trilobites, crustacean scorpions appear, wide distribution of armored agnathans (the first true vertebrates), the appearance of echinoderms, the first land animals -arachnids . Exit to sushi plants, the first land plants( psilophytes )

Devonian

OK. 400 million

dl. 55 million

Climate: alternation of dry and rainy seasons. Glaciation on the territory of modern South America And South Africa

Age of fish: The appearance of fish of all systematic groups (nowadays you can find: coelacanth (lobe-finned fish), protoptera (lungfish)), the extinction of a significant number of invertebrates and most jawless animals, the appearance of ammonites-cephalopods with spirally twisted shells. The development of land by animals: spiders, ticks. The appearance of terrestrial vertebrates -stegocephalians (shell-headed )(the first amphibians; descended from lobe-finned fish) Development and extinction of psilophytes. The emergence of spore-forming plants: lycophytes, horsetail-like plants, fern-like plants. The emergence of mushrooms

Carbon

(Carboniferous period)

OK. 345

million

dl. 65 million

Worldwide distribution of swamps. The warm, humid climate gives way to cold and dry climates.

The flourishing of amphibians, the appearance of the first reptiles -cotylosaurs , flying insects, reduction in the number of trilobites. On land - forests of spore plants, the appearance of the first conifers

Permian

280 million

Dl. 50 million

Climate zonation. Completion of mountain building, retreat of the seas, formation of semi-enclosed reservoirs. Reef formation

The rapid development of reptiles, the emergence of animal-like reptiles. Extinction of trilobites. Disappearance of forests due to the extinction of tree ferns, horsetails and mosses. Permian extinction (96% of all marine species, 70% of terrestrial vertebrates)

During the Paleozoic, an important evolutionary event occurred: the settlement of land by plants and animals.

Aromorphoses in plants: appearance of tissues and organs (psilophytes); root system and leaves (ferns, horsetails, mosses); seeds (seed ferns)

Aromorphoses in animals: formation of bony jaws (gnatostome armored fish); five-fingered limbs and pulmonary respiration (amphibians); internal fertilization and accumulation of nutrients (yolk) in the egg (reptiles)

MESOZOIC

(middle life) era of reptiles

Triassic

230 million

Length: 40 million

Supercontinent split

(Laurasia, Gondwana) movement of continents

The heyday of reptiles is the “age of dinosaurs”, turtles, crocodiles, and tuataria appear. The emergence of the first primitive mammals (ancestors were ancient toothed reptiles), true bony fish. Seed ferns are dying out, ferns, horsetails, lycophytes are common, gymnosperms are widespread

Yura

190 million

Length 60 million

The climate is humid, then changes to arid at the equator, the movement of continents

The dominance of reptiles on land, in the ocean and air, (flying reptiles - pterodactyls) the appearance of the first birds - Archeopteryx. Ferns and gymnosperms are widespread

Chalk

136 million

Dl. 70 million

Cooling of the climate, retreat of the seas, is replaced by an increasesocean

The appearance of true birds, marsupials and placental mammals, the flourishing of insects, angiosperms appear, a decrease in the number of ferns and gymnosperms, the extinction of large reptiles

Aromorphoses of animals: the appearance of a 4-chambered heart and warm-bloodedness, feathers, a more developed nervous system, an increase in the supply of nutrients in the yolk (birds)

Carrying babies in the mother's body, feeding the embryo through the placenta (mammals)

Aromorphoses of plants: the appearance of a flower, protection of the seed by shells (angiosperms)

Cenozoic

Paleogene

66 million

dl. 41 million

A warm, uniform climate is established

Fish are widespread, many cephalopods are dying out, on land: amphibians, crocodiles, lizards, many orders of mammals appear, including primates. Insect bloom. The dominance of angiosperms, tundra and taiga appear, numerous idioadaptations appear in animals and plants (for example: self-pollinating, cross-pollinating plants, a variety of fruits and seeds)

Neogene

25 million

length 23 million

Movement of continents

Dominance of mammals, common: primates, ancestors of horses, giraffes, elephants; saber-toothed tigers, mammoths

Anthropocene

1.5 million

Characterized by repeated climate changes. Major glaciations of the Northern Hemisphere

The emergence and development of man, animals and vegetable world acquire modern features

There is a whole complex of sciences that study the main stages of the development of life on Earth, all of them consider this issue from a variety of perspectives, because this is a fundamental problem of natural science. The importance of paleontology, which studies the remains of plants and animals of past eras, is very important; it is directly related to the study of the evolution of the world.

This science studies the basic ones by reconstructing the appearance, external similarities and differences, the lifestyle of prehistoric, already extinct animals and plants, and also determines the approximate time of existence of a particular species. But paleontology could not exist as a separate science without many others supporting it; this science is at the intersection of biological and geological disciplines. The main stages of the development of life on Earth are recreated using such disciplines as:

historical geology;
stratigraphy;
paleography;
comparative anatomy;
paleoclimatology and many others.

They are all interconnected, without one the others cannot exist.

Geological time

To highlight the main stages in the development of life on Earth, it is necessary to have an understanding of such a concept as geological time. How did people manage to identify certain time stages? The whole secret lies in the study of rocks. The fact is that rocks that arose at a later time are superimposed on top of those that existed earlier. And the age of these layers can be determined by studying the fossils remaining in them.

Among all their diversity, the so-called guiding fossils stand out, which are the most numerous and widespread. Unfortunately, it is impossible to establish absolute age using rocks, but even here scientists do not stop, extracting this knowledge from volcanic rocks. As is known, they arise from magma. This is how the main stages of the development of life on earth are identified.

Briefly, the process of determining the absolute age of volcanic rocks looks like this: igneous rocks contain some elements, if you determine their content in the rock, you can quite accurately determine the absolute age of the rock. Of course, errors are possible, but they do not exceed five percent. In addition, the age of our planet is also determined; all scientists adhere to their own figure, but the generally accepted value is five billion years. Now let’s highlight the main stages, which will be a good helper for us in this case.

Eras, epochs and periods

In total, paleontologists distinguish five stages or, in other words, eras, each of which is divided into periods, all of them consist of eras, and the last ones - of centuries. The Archean and Proterozoic eras are the most ancient times, which span about three billion years. They are distinguished by the complete absence of vertebrates and land plants, which appear in the “era ancient life", spanning over three hundred million years. Next comes the “era of average life,” the Mesozoic (one hundred and seventy-five million years), its distinctive features- development of reptiles, birds, mammals, plants, both flowering and angiosperms.

The most recent, fifth, era is the Cenozoic, also called the “era of new life”, it began seventy million years ago, and we still live in it. is different rapid development mammals and the emergence of humans. Now we have briefly examined the stages of the development of life on Earth; we propose to consider each era separately.

Archean era

This stage covers the period from three thousand nine hundred to two thousand six hundred million years ago. Some sedimentary rocks, that is, formed with the help of particles of the aquatic environment, remained in Africa, Greenland, Australia and Asia. They all contain:

biogenic carbon;
stromatolites;
microfossils.

Moreover, the origin of the latter in this era is not entirely clear; for example, in the Proterozoic they are associated with cyanobacteria. In the Archean era, all organisms were prokaryotes, and the source of oxygen was sulfates, nitrates, nitrites, and so on. All existing organisms on the planet externally resembled films of mold, and were mainly located at the bottom of reservoirs, in volcanic areas.

Proterozoic era

It is important to mention that this era is also divided into periods, of which there are three. It is also the longest period in our history (approximately two million years). If we consider the boundary of this era and the Archean, then it was during this period that our planet changed greatly, land and water spaces were redistributed. The earth was an icy desert, but at the end of this period the percentage of oxygen reached one percent, which contributed to the sustainable functioning of single-celled organisms, bacteria and algae developed.

At the end of the Proterozoic, multicellular animals formed; this period is also called the “age of jellyfish.” Single-celled organisms are replaced by multicellular ones, which qualitatively change the composition of the atmosphere, which contributes to the development of life on our planet.

Paleozoic

It includes as many as six periods, the first half is called the early Paleozoic, and the second - the late. The early and late Paleozoic periods differ in flora and fauna.

At the first stage, evolution can be traced exclusively in underwater world, the settlement of land began only in the Devonian, which belongs to the late Paleozoic.

Mesozoic era

We are now entering a most interesting era, a rich, mysterious and diverse life evolving over a period of approximately one hundred and eighty-five million years. As can be seen from the table, it is also divided into three periods. The Cretaceous, in comparison with the Jurassic and Triassic, is the longest (seventy-one million years).

As for the climate, it all depends on the location of the continents. The differences from our climate are that:

it was much warmer than the modern one;
there were no temperature differences between the equators and the poles.

In addition, the air was humid, which contributed to the rapid development of living organisms.

If we move on to issues of fauna, the most unique group is the well-known dinosaurs. They took a dominant position over other life forms due to the structure of their body, physiological data and reaction.

So, when examining the question of what are the main stages in the development of life on Earth, we have identified five stages. To complete the picture, it remains to consider one more. We suggest you start right now.

Cenozoic era

This new era, which continues to this day. Continents have acquired modern look, the last dinosaurs have disappeared, the Earth is dominated by plants and animals that are quite familiar to us. We reviewed the main stages of the development of life on Earth briefly, analyzed all the stages separately, and our goal was achieved.

For a long time historical development life on Earth, a great diversity of biological species and systems has arisen.

1) In what environment did the first living creatures on Earth arise? Describe them.

Answer: Formation and development took place in aquatic environment, which is rich in organic and inorganic substances was like broth.

2) Based on what data is the history of the Earth divided into major stages? What other stages are they divided into?

Answer: The history of the Earth and the development of life on the planet is divided into stages - eras. Periods are distinguished in eras, and epochs are distinguished in periods.

3) Fill out the table "The Development of Life on Earth."

Era name	Duration million years	Animal and plant life
Katarhey	began about 4500 million years ago	synthesis of the first organic compounds
Archaea	began approximately 3500 million years ago	photosynthesis, eukaryotic cells, sexual process, multicellularity
Proterozoic	began 2500 million years ago	bilateral symmetry, three layers, organ systems, hindgut and anus
Paleozoic	began 534 million years ago	the appearance of organisms with a mineral skeleton, the differentiation of the plant body into tissues, the division of the animal body into sections, the formation of jaws, the appearance of limb girdles in vertebrates. Division of the plant body into organs, transformation of fins into terrestrial limbs, appearance of air respiration organs, internal fertilization, dense egg membranes, keratinization of the skin, formation of seeds, formation of a pollen tube and seed
Mesozoic	began about 248 million years ago	4-chambered heart, complete separation of arterial and venous blood flow, mammary glands, the appearance of the flower and fruit, the formation of the uterus
Cenozoic	began more than 65 million years ago	intensive development of the cerebral cortex, thinking, upright posture

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

Answer: Vertebrates appeared in fresh waters- sharks and bony fish - lungfish and lobe-finned fish; plants, animals and fungi came to land.

5) What were the first organisms that left the aquatic environment and began their “triumphant march” across land? When and how was soil formed?

Answer: Prokaryotes (bacteria and cyanobacteria) were the first to reach land. This happened back in the Archean. With the emergence of prokaryotes on land, the process of soil formation began.

6) What features were characteristic of the first inhabitants of land?

Answer: The appearance of a nocturnal and ancient lifestyle in organisms, development rhythms were developed, leaves and branching of shoots developed in plants.

7) Why do the most ancient, primitive and highly organized animals simultaneously exist in the same habitat at the same time? Illustrate your answer with examples.

Answer: All organisms are interconnected.

The main stages of the evolution of flora and fauna

Geochronological history of the Earth. The history of the Earth is usually divided into periods of time, the boundaries of which are major geological events: mountain-building processes, the rise and fall of land, changes in the outlines of continents, and ocean levels. Movements and fractures of the earth's crust that occurred at different times geological periods, were accompanied by increased volcanic activity, as a result of which a huge amount of gases and ash were released into the atmosphere, which reduced the transparency of the atmosphere and contributed to a decrease in the amount of solar radiation reaching the Earth. This was one of the reasons for the development of glaciations, which caused climate change, which had a strong impact on the development of the organic world. In the process of evolution, new forms of organisms constantly arose, and previous forms, which turned out to be unadapted to new conditions of existence, died out.

For many millions of years, the remains of once-living organisms accumulated on the planet. Based on the finds of fossil forms in the sediments of the earth's strata, it is possible to trace true story wildlife (Table 4.2). The use of the radioisotope method makes it possible to determine with great accuracy the age of rocks in places where paleontological remains occur and the age of fossil organisms.

Based on paleontological data, the entire history of life on Earth is divided into eras and periods.

The main stages of plant evolution. In the Proterozoic era (about 1 billion years ago), the trunk of the most ancient eukaryotes was divided into several branches, from which plants, fungi and animals arose. Most of the plants of this period floated freely in the water, some of them were attached to the bottom.

Table 4.2. Geochronological scale of the Earth.

	Period	Beginning (millions of years ago)	Evolutionary events

Cenozoic (new life)	Quaternary		Plants: The extinction of many plant species, the decline of woody forms, the flourishing of herbaceous forms; the flora takes on a modern appearance. Animals: Development of many groups of marine and freshwater mollusks, corals, echinoderms, etc. Formation of existing communities, the emergence and evolution of humans.
	Neogene (Neogene)		Plants: Predominance of angiosperms and conifers, retreating forests, increasing area of steppes. Animals: The species composition of invertebrates is approaching modern ones. The rise of placental mammals similar to modern ones. The emergence of great apes.
	Paleogene (Paleogene)		Plants: Bloom of diatoms and major groups of angiosperms. Dominance of bivalves and gastropods. Animals: Extinction of the oldest mammals. Development of marsupials and primitive placentals: insectivores, ancient ungulates, ancient predators. The beginning of the development of anthropoids.
Mesozoic (middle life)	Cretaceous (chalk)		Plants: At the beginning of the period, the dominance of gymnosperms and the appearance of angiosperms, which predominate in the second half of the period. Animals: Development of bivalves and gastropods, other invertebrates. The development of large reptiles in the first half of the period and their extinction in the second half of the period. Development of mammals and birds.
	Jurassic (Jurassic)		Plants: Appearance of diatoms. Dominance of ferns and gymnosperms. The heyday of cephalopods and bivalves. The flourishing of reptiles: terrestrial, waterfowl, flying. The appearance of ancient birds, the development of ancient mammals.
	Triassic (Triassic)		Plants: Extinction of seed ferns. Development of gymnosperms. Animals: The extinction of many animals that flourished during the Paleozoic era. The extinction of stegocephals, the development of reptiles, the appearance of ancient mammals.
Paleozoic (ancient life)	Permian		Plants: Distribution of the first groups of gymnosperms. Animals: Reducing the number of speciescartilaginous, lobe-finned and lungfishes. The development of stegocephals, reptiles, some of which were ancestral to mammals and birds.
	Carboniferous (carbon)		Plants: Blooming lycophytes, horsetail ferns, pteridophytes, seed ferns; the appearance of conifers. Animals: The Rise of Ancient Marine Invertebrates. The appearance of primary wingless and ancient winged insects. Distribution of sharks, stegocephalians. The appearance and flourishing of amphibians. The appearance of ancient reptiles.
	Devonian(Devonian)		Plants: The flourishing of rhiniophytes, their extinction by the beginning of the Late Devonian. The emergence of modern types of vascular plants. Animals: The flourishing of ancient invertebrates, the appearance of arachnids. The flourishing of armored, lobe-finned and lungfishes. At the end of the period, the first tetrapods appeared - stegocephals (ancient amphibians).
	Silurian (Silurian)		Plants: The emergence of modern groups of algae and fungi. At the end of the period, the first land plants appeared with certainty. The appearance of terrestrial arthropods - scorpions. The appearance of ancient armored and cartilaginous fish.
	Ordovician (Ordovician)		Plants: Abundance of seaweed. Presumable appearance of the first land plants - rhinophytes. The appearance of the first jawless vertebrates.
	Cambrian (Cambrian)		Plants: Life is concentrated in the seas. Evolution of algae. Animals: Development of multicellular forms. The flourishing of marine invertebrates with chitin-phosphate shells.
Proterozoic (early life)	Late Proterozoic		Plants: Algae development, Animals: Various multicellular primitive organisms that do not have skeletal structures.
Proterozoic (early life)	Early Proterozoic		Plants and animals: Development of unicellular prokaryotic and eukaryotic photosynthetic organisms. The emergence of the sexual process.
	No under section		: The emergence of life on Earth, the appearance of the first cells - the beginning of biological evolution. The appearance of anaerobic autotrophic organisms, bacteria, cyanobacteria.
Katarhey	No under section		Chemical evolution leading to the emergence of biopolymers.

1. Archean era - oldest stage in the history of the Earth, when life arose in the waters of the primordial seas, which was originally presented precellular its forms and the first cellular organisms. Wasp analysis Dock rocks of this age show that bacteria and blue-greens lived in the aquatic environment.

2 . Proterozoic era. On the verge of the Archean and Proterozoic eras, the structure and function of organisms became more complex: multicellularity and the sexual process arose, which increased the genetic heterogeneity of organisms and provided extensive material for selection; photosynthetic plants became more diverse. The multicellularity of organisms was accompanied by an increase in the specialization of cells, their integration into tissues and functional systems.

It is quite difficult to trace in detail the evolution of animals and plants in the Proterozoic era due to the recrystallization of sedimentary rocks and the destruction of organic remains. In the deposits of this era only imprints of bacteria, algae, lower types of invertebrates and lower chordates. A major step in evolution was the appearance of organisms with bilateral symmetry of the body, differentiated into anterior and posterior sections, left and right sides, and a separation of the dorsal and ventral surfaces. The dorsal surface of the animals served as protection, and the ventral surface housed the mouth and food-grasping organs.

3. Paleozoic era. The flora and fauna reached great diversity, and terrestrial life began to develop.

There are six periods in the Paleozoic: Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian. In the Cambrian period, life was concentrated in water (it covered a significant part of our planet) and was represented by more advanced multicellular algae, having a dissected thallus, thanks to which they more actively synthesized organic matter and were the original branch for terrestrial leafy plants. Invertebrates are widespread in the seas, including brachiopods, and from arthropods - trilobites. An independent type of two-layered animals of that period were archaeocyaths, which formed reefs in ancient seas. They died out without leaving descendants. Only people lived on land bacteria And mushrooms.

During the Ordovician period, the climate was warm even in the Arctic. In the fresh and brackish waters of this period, planktonic species reached their peak development. seaweed, various corals from the phylum Coelenterata, there were representatives of almost all types invertebrates including trilobites, mollusks, echinoderms. Bacteria were widely represented. The first representatives of jawless vertebrates appear - Scutellaceae.

At the end of the Silurian period, due to mountain-building processes and a reduction in the area of seas, some algae found themselves in new environmental conditions - in small reservoirs and on land. Many of them died. However, as a result of multidirectional variability and selection, individual representatives acquired characteristics that contributed to survival in new conditions. The first terrestrial spore plants appeared - psilophytes. They had a cylindrical stem about 25 cm in height, instead of leaves there were scales. Their most important adaptations are the appearance of integumentary and mechanical tissues, root-like outgrowths - rhizoids, as well as the elementary conduction system.

In the Devonian, the number of psilophytes sharply decreased, they were replaced by their transformed descendants, higher plants - lycophytes, mossy And ferns, in which real vegetative organs (root, stem, leaf) develop. The emergence of vegetative organs increased the efficiency of the function of individual parts of plants and their vitality as a harmoniously integral system. The emergence of plants on land preceded the emergence of animals. On Earth, plants accumulated biomass, and in the atmosphere - a supply of oxygen. The first invertebrate land dwellers were spiders, scorpions, centipedes. There were many fish in the Devonian seas, among them - jaw armored, having an internal cartilaginous skeleton and an external durable shell, movable jaws, and paired fins. Fresh water bodies were inhabited lobe-finned fish that had gill and primitive pulmonary respiration. With the help of fleshy fins, they moved along the bottom of the reservoir, and when dry, they crawled into other reservoirs. A group of lobe-finned fish were the ancestors of ancient amphibians - stegocephalus. Stegocephalians lived in swampy areas, went out onto land, but reproduced only in water.

In the Carboniferous period, giant ferns spread, which, in a warm, humid climate, settled everywhere. During this period they reached their peak ancient amphibians.

During the Permian period, the climate became drier and colder, which led to the extinction of many amphibians. Towards the end of the period, the number of amphibian species began to decline sharply, and only small amphibians (newts, frogs, toads) have survived to this day. Tree-like spore-forming ferns replaced seed ferns, which gave rise to gymnosperms. The latter had a developed taproot system and seeds, and fertilization took place in the absence of water. The extinct amphibians were replaced by a more progressive group of animals descended from stegocephalians - reptiles. They had dry skin, denser cellular lungs, internal fertilization, a supply of nutrients in the egg, and protective egg membranes.

4. Mesozoic era includes three periods: Triassic, Jurassic, Cretaceous.

Widespread in the Triassic gymnosperms, especially conifers, which have taken a dominant position. At the same time they settled widely reptiles: Ichthyosaurs lived in the seas, plesiosaurs lived in the air - flying lizards, reptiles were also represented on the ground in a variety of ways. Giant reptiles (brontosaurus, diplodocus, etc.) soon became extinct. At the very beginning of the Triassic, a group of small animals with a more advanced skeletal and dental structure separated from reptiles. These animals acquired the ability to give birth, a constant body temperature, they had a four-chambered heart and a number of other progressive organizational features. These were the first primitive mammals.
In the deposits of the Jurassic period of the Mesozoic o6 the remains of the first bird were also found - Archeopteryx. It combined in its structure the characteristics of birds and reptiles.

In the Cretaceous period of the Mesozoic, a branch of plants that had a seed reproduction organ, the flower, separated from the gymnosperms. After fertilization, the ovary of the flower turns into a fruit, so the developing seeds inside the fruit are protected by the pulp and membranes from unfavorable environmental conditions. The variety of flowers and various adaptations for pollination and distribution of fruits and seeds allowed angiosperm (flowering) plants to spread widely in nature and take a dominant position. In parallel with them, a group of arthropods developed - insects which, being pollinators of flowering plants, greatly contributed to their progressive evolution. In the same period there appeared real birds And placental mammals. Signs high degree their organizations have a constant body temperature | complete separation of arterial and venous blood flow, increased metabolism, perfect thermoregulation, and in mammals, in addition, viviparity, feeding of young with milk, development of the cerebral cortex - allowed these groups to also occupy a dominant position on Earth.

5. Cenozoic era is divided into three periods: Paleogene, Neogene and Quaternary.

In the Paleogene, Neogene and early Quaternary periods, flowering plants, thanks to the acquisition of numerous individual adaptations, occupied most of the land and represented subtropical and tropical flora. Due to the cooling caused by the advance of the glacier, the subtropical flora retreated to the south. The composition of terrestrial vegetation of temperate latitudes began to predominate deciduous trees, adapted to the seasonal rhythm of temperatures, as well as shrubs and herbaceous plants. The flowering of herbaceous plants occurs in the Quaternary period. Warm-blooded animals have become widespread:
birds and mammals. In glacial times, cave bears, lions, mammoths, and woolly rhinoceroses lived, which gradually died out after the retreat of glaciers and warming of the climate, and animal world acquired a modern look.

The main event of this era is the formation of man. By the end of the Neogene, small tailed mammals lived in the forests - lemurs And tarsiers. From them came the ancient forms of monkeys - parapithecus, which led an arboreal lifestyle and fed on plants and insects. Their distant descendants are living today gibbons, orangutans and extinct small tree monkeys - Dryopithecus. Dryopithecus gave rise to three lines of development that led to chimpanzee, gorilla, and also extinct Australopithecus. Originated from Australopithecus at the end of the Neogene a reasonable person.

The main features of the evolution of the animal world are as follows:

progressive development of multicellularity and, as a consequence, specialization of tissues and all organ systems;
a free lifestyle, which determined the development of various behavioral mechanisms, as well as the relative independence of ontogenesis from fluctuations in environmental factors;
the emergence of a hard skeleton: external in some invertebrates (arthropods) and internal in chordates;
progressive development of the nervous system, which became the basis for the emergence of conditioned reflex activity

Taken from websites.

Archaea- ancient life. Lasted about 900 million years, from 3500 to 2600 million years. There are few remains of organic life. Archean rocks contain a lot of graphite, it is believed that graphite was formed from the remains of living organisms. Discovered stromatolites- cone-shaped calcareous formations of biogenic origin. Many reserves of sulfur, iron, copper, nickel, and cobalt are of bacterial origin. Living organisms of the Archaea were first represented by anaerobic prokaryotes, later blue-green ones appeared. Photosynthesis of blue-greens is the most important aromorphosis of the Archean era. Thanks to their vital activity, the atmosphere is enriched with oxygen.

Proterozoic era.

Proterozoic- era of primary life. Duration from 2600 million years to 570 million years, that is, about 2 billion years. The surface of the planet was a bare desert, life developed mainly in the seas. This longest era is characterized by the formation of the largest deposits of iron ores, formed due to the activity of bacteria. In the Proterozoic era, fundamental aromorphoses occurred:

The most important aromorphosis was the formation of bilateral symmetry in actively moving organisms.

During this era, all departments of algae are formed, and the thallus of many becomes lamellar. Animals of that time are characterized by the absence of skeletal formations; the end of the Proterozoic is sometimes called "the age of jellyfish". Annelids appear, from which mollusks and arthropods originated. The amount of oxygen in the atmosphere has reached 1% of the current level.

Paleozoic- the era of ancient life, the duration of which is from 570 to 230 million years. During this era, significant aromorphoses occurred in the plant and animal world, associated both with life in water and with the development of land. Divided into six periods: Cambrian, Ordovician, Silurian, Devonian, carbon, Permian.

Cambrian and Ordovician plants inhabit the seas and are represented by all departments of algae. In the Silurian period (440 million years ago), in the zone of ebbs and flows from green plants, the first terrestrial higher plants appeared - psilophytes(naked plants) (Fig. 361). The appearance of integumentary, mechanical, and conductive tissues were the aromorphoses that helped plants to emerge into the air. Psilophytes do not yet have roots; they absorb water and mineral salts with the help of rhizoids. Scales on the stem of psilophytes increased the surface area for photosynthesis.

In the Devonian, pteridophytes appear - herbaceous and tree-like horsetails, mosses, and ferns. The appearance of roots and leaves provided sufficient air and mineral nutrition for a variety of ferns. Fern-like spores reproduce by single-celled spores, and in damp places they develop into germs that form reproductive cells. Fertilization requires water; an adult plant develops from the zygote.

The Carboniferous has a warm and humid tropical climate. Ferns reach gigantic sizes - up to 40 m in height. Carboniferous forests subsequently led to the formation of huge deposits coal. At the same time, two most important aromorphoses occurred in the Carboniferous, as a result of which higher seed plants appeared: firstly, pollination with

with the help of the wind, when pollen with male reproductive cells travels through the air to plant organs containing female reproductive cells, water is no longer needed for fertilization; secondly, after fertilization, seeds are formed. Such plants were seed ferns.

Seed ferns gave rise to the development of gymnosperms. During the Permian period, the climate became drier and colder. Tropical forests remain near the equator; gymnosperms spread throughout the rest of the territory.

Animals of the Cambrian period are characterized by a variety of trilobites - the oldest arthropods; during this period, animals with a mineralized skeleton appeared.

In the Ordovician period, the first chordates with an internal skeleton appeared, the distant descendants of which are lancelets and cyclostomes - lampreys and hagfish.

In the Silurian seas, echinoderms and jawless armored “fish” appear, which only superficially resembled real fish and did not have jaws. Capture and hold large production was impossible with such a mouth. The first arthropods come to land - scorpions and spiders.

In the Devonian, insects appeared on land, and real fish - cartilaginous fish (sharks) and fish with a bony skeleton - already swam in the seas. As a result of mutations and selection, the third pair of gill arches turned into jaws, with the help of which they could feed on large prey.

The most interesting among bony fishes were lungfishes and freshwater lobe-finned fishes, which had lungs along with gills. Warm water and an abundance of vegetation in fresh water bodies served as prerequisites for the development of additional respiratory organs; the pharyngeal pouches of lungfish and lobe-finned animals gradually turn into lungs. Freshwater lobe-finned fish also had powerful paired limbs (Fig. 362) and were better adapted to life in shallow coastal waters, from which stegocephals (shell-headed amphibians) evolved (Fig. 363).

In the Carboniferous, winged insects appeared on land; some dragonflies had a wingspan of up to 70 cm. The abundance of arthropods on land caused the appearance of a large number of different forms of ancient amphibians (up to 6 m in length).

Further development of land led to the appearance of reptiles and was accompanied by a number of aromorphoses: the surface of the lungs increased, dry scaly skin protected from evaporation, internal fertilization and the laying of large eggs allowed embryos to develop on land.

In the Permian period, climate change was accompanied by the disappearance of stegocephalians and the spread of reptiles.

Mesozoic era.

Mesozoic- the era of average life, began 230, ended 67 million years ago. It is divided into three periods: Triassic, Jurassic and Cretaceous. The vegetation of the first two periods of the Mesozoic era was represented by gymnosperms and ferns, and the extinction of tree ferns continued. At the beginning of the Cretaceous period (130 million years ago), the first angiosperms appeared. The appearance of the flower and fruit are major aromorphoses that led to the appearance of angiosperms. With the help of a flower, the pollination process was facilitated, and the ovules located inside the ovary of the pistil were better preserved. The walls of the pericarp protected the seeds and facilitated their dispersal.

Rice. 364. Archeopteryx.

In the animal world of the Mesozoic era, insects and reptiles reached the greatest distribution. In the Triassic, reptiles returned to the water for the second time, plesiosaurs lived in shallow waters, and ichthyosaurs, reminiscent of modern dolphins, hunted far from the shore. The first oviparous mammals appear; unlike reptiles, their high metabolic rate allows them to maintain a constant body temperature.

In the Jurassic period, some herbivorous reptiles reached gigantic sizes, and very large predatory dinosaurs appeared - tyrannosaurs, whose body length reached 12 meters. Some reptiles master the airspace - flying lizards (pterosaurs) appear. In the same period, the first birds also appeared; Archeopteryx (the size of a pigeon) retains many of the characteristics of reptiles - its jaws have teeth, three fingers protrude from its wing, its tail consists of large number vertebrae (Fig. 364).

At the beginning of the Cretaceous period, the dominance of reptiles on land, in water and in the air remained, some herbivorous reptiles reached a mass of 50 tons. Marsupials and placental mammals appeared, and the parallel evolution of flowering plants and pollinating insects continued. At the end of the Cretaceous period, the climate becomes cold and dry. The area occupied by vegetation is decreasing, giant herbivores are dying out, and then predatory dinosaurs are dying out. At the end of the Mesozoic era, some mammals from the order of insectivores began to lead an arboreal lifestyle, from which the ancestral forms of primates appeared at the beginning of the Cenozoic era.

Cenozoic era.

Cenozoic- era of new life. It lasts 67 million years and is divided into two unequal periods - Tertiary (Paleogene and Neogene) and Quaternary (Anthropocene). In the first half of the Tertiary period (Paleogene), a warm tropical climate re-established itself over most of the Earth; in the second half (Neogene), tropical forests were replaced by steppes, and monocotyledonous plants spread. In the Quaternary period, which lasts about 1.5 million years during the Ice Age, Eurasia and North America were subject to glaciations four times.

As a result of steppe, which occurred in the second half of the Tertiary period, some primates were forced to descend to the ground and adapt to life in open spaces. These were the ancestral forms of people - hominids, upright primates. The other part remained to live in the tropical forests and became the ancestors of great apes - pongid. At the end of the Tertiary period, ape-men appear from hominids, Pithecanthropus.

In the Quaternary period, the cold climate led to a decrease in the level of the world's oceans by 60 - 90 m, glaciers were formed and descended to the south, the ice thickness of which reached tens of meters, the water evaporated, but did not have time to melt. Land bridges were formed between Asia and North America, between Europe and the British Isles. Animal migrations from continent to continent took place along these land bridges. About 40 thousand years ago, ancient people left Asia for North America along the Beringian land bridge. As a result of cooling and the appearance of people who hunted animals, many large animals disappeared: saber-toothed tigers, mammoths, woolly rhinoceroses. Near the sites of ancient people, the remains of many dozens of mammoths and other large animals are discovered. Due to the extermination of large animals 10 - 12 thousand years ago, people were forced to move from gathering and hunting to agriculture and cattle breeding.

The development of life on Earth - concept and types. Classification and features of the category “Development of life on Earth” 2017, 2018.