When did the first plants appear? The first land plants. Plants during the Carboniferous period

In this article we will discuss an important and interesting topic - the emergence and development flora on the planet. Today, walking in the park during the lilac bloom, picking mushrooms in the autumn forest, watering house flowers on the windowsill, infusing chamomile decoction during an illness, we rarely think about what the Earth looked like before the appearance of plants. What was the landscape like at the time when unicellular organisms were just emerging or the first weak land plants appeared? What did forests look like in the Paleozoic and Mesozoic? Imagine that the ancestors of those half-meter ferns that now modestly hide in the shade of spruce trees, 300 million years ago reached a height of 30 meters or more!

Let's list the main stages in the emergence of the living world.

Origin of life

1. 3, 7 billion years ago arose first alive organisms. The time of their appearance (very approximately, with a gap of hundreds of millions of years) can today be guessed from the deposits they formed. For a million and a half years cyanobacteria learned oxygen photosynthesis and multiplied so much that they became responsible for the oversaturation of the atmosphere with oxygen approximately 2.4 billion years ago - this led to the extinction of anaerobic organisms for which oxygen was poison. The living world of the Earth has changed radically!

2. 2 billionyears ago there were already different unicellular: both autotrophs and heterotrophs. These p first unicellular did not have nuclei and plastids - the so-called heterotrophic prokaryotes (bacteria). They were the ones who gaveimpetus for the appearance of the first single-celled organisms plants.

3. 1, 8 billionyears ago, nuclear unicellular organisms arose,that is, eukaryotes, soon (by geological standards)Typical animal and plant cells appeared.

The emergence of multicellular plants

1. Near 1, 2 billion years ago on the basis of unicellular organisms arosemulticellular algae.

2. At that time, life existed only in warm seas and oceans, but living organisms were actively developing and progressing - preparing for the development of land.

Plants coming to land

1. 4 2 0 millionyears ago the first land plants appeared - mosses And psilophytes (rhiniophytes). They appeared in many places on the planetindependently of each other, from different multicellular algae.Of course, at first they only explored the coastal edge.

2. Psilophytes(For example, rinia) lived along the banks, in shallow waters, similar to modern mossocks. They were small weak plants, whose life was complicated by the lack of shoots and roots. Instead of roots with which to properly cling to the soil, psilophytes had rhizoids. The upper part of the psilophyte contained a green pigment and was capable of photosynthesis. These pioneers, bold invaders of land, became extinct,but they were able to give rise to pteridophytes.

4. Mosses - for all their unusualness, beauty and ubiquity these days - they have become a dead end branch yu of evolution. Having arisen hundreds of millions of years ago, they were never able to give rise to any other groups of plants.

Most modern scientists believe that planet Earth was formed a little earlier than four and a half billion years ago. The earliest remains of extinct organisms are found in rocks dating back 3.8 billion years. The first inhabitants of the Earth were anaerobic bacteria, that is, they did not use oxygen for breathing, which was not yet in the atmosphere.

It is believed that for the first time the process of photosynthesis began to take place in bacteria. Photosynthesis is the most important natural process when, when interacting sunlight, water and carbon dioxide, organic substances and free oxygen are formed.

The first simple unicellular algae and fungi appeared about 2 billion years ago. Their remains were found in sediments of the Proterozoic era in Greenland and Canada. At the same time, the first multicellular plants appeared. The development of life on Earth, the emergence of both plants and animals, were closely related to the process of photosynthesis.

Scientists believe that blue-green algae (this is their name, not just a color designation) and mushrooms are the first representatives of the plant world on Earth. These are lower plants.

More than 2 billion years ago, the first land plants resembled the mosses we see today in damp, shady places.

More complex plants arose about 400,000,000 years ago. They resembled modern ferns. Ferns were the first to have roots, stems, and leaves. These are signs of higher plants.

By the time dinosaurs appeared, the Earth was already covered with forests. These plants reproduced by seeds.

Pines and others coniferous trees appeared later, 300,000,000 years ago. This group of trees includes numerous representatives such as pine, spruce, Canadian spruce, cedar, larch. All these trees hide their seeds in cones.

First flowering plants appeared 150,000,000 years ago. Their well-protected seeds gave them a great advantage over plants whose seeds were not so well protected. Therefore, they have increased in number and type. Flowering plants are everywhere these days.

A berry is a fruit that has many seeds inside and no seeds. When the berry is ripe, it has a fleshy and juicy pericarp, like strawberries, grapes, crow's eyes, lingonberries, blueberries, blueberries, and cranberries. So, a cherry is not a berry, but a tomato is a berry? Yes, from the point of view of a botanist, this is true. And citrus fruits: orange, lemon, tangerine, grapefruit,...

Beech is found in forests in temperate regions of the Northern Hemisphere. These are large trees with a height of 25-40 m and a trunk diameter of up to two meters. The trunk, smooth as a column, is covered with gray, smooth bark. The leaves are simple, their shape is an oblong ellipse. In autumn, fruits ripen on the tree - triangular nuts. A plus usually contains 2, less often 4 nuts, in which...

This plant is found only in Eastern and South-East Asia. Europeans knew nothing about him for a very long time, although folk medicine Korea, Japan and China have been using lemongrass since time immemorial. Schisandra is an excellent tonic. It increases the tone of the body and gives a person vigor. Schisandra tincture prevents and relieves fatigue during long periods of time physical activity. Lemongrass -...

When we hear the word “mushroom,” we remember boletuses, honey mushrooms, russula and even toadstools that we knew from childhood - in a word, something consisting of a cap and a stem that grows in the forest and ends up in our basket if it is edible, or which is so pleasant to give in kick if it looks like a toadstool. But this is, so to speak, the “traditional” form of mushrooms. In fact...

In temperate climates, the apple tree is the most important fruit tree. Scientists have counted at least 10 thousand varieties of apple trees. They were taken out different varieties wild plants. All these varieties are adapted to different climates and soils. But the apple region is rightfully considered middle lane Russia, and the most famous and beloved variety of apples is amber-yellow, fragrant, sweet and sour and crispy...

It is absolutely impossible to imagine life without tea. This aromatic drink contains vitamins B1, B2, C, P, PP, tannin, caffeine and other beneficial substances. Oil used in perfumery is extracted from the seeds. Medicines are made from waste leaves. The homeland of tea is the subtropical forests of Southeast Asia, the southern regions of China, Burma, North Vietnam and the state of Assam in northeast India...

Bright orange nasturtiums are also called capuchin nasturtiums because of the pointed shape of the flower, reminiscent of the hood of a capuchin monk. At home, in tropical America, you can find up to 80 species of nasturtiums. They grow in tropical rainforests, arid steppes, and mountains. They are also colored a beautiful yellow, orange colors, but there are blue and purple nasturtiums. All tropical nasturtiums...

Captain James Cook; while visiting the islands of New Zealand, I could not help but notice a plant that grew along the banks of streams and along the edges of swamps. Its leaves, very similar in shape and... swords of the same size covered the coastal hills, and were also found in thickets of evergreen bushes and even in dry rocky places. It was New Zealand flax, which later became famous...

To this day, museums contain elegant furniture made of ebony with birch inlays - tables, armchairs, bureaus. It was especially in fashion under Peter I and until the end of the 18th century. Then furniture made of “mahogany” appeared in rich houses. For a long time it was considered the most precious of decorative species. And still in...

Palm trees feed, water, and clothe people. The most useful of them is the coconut palm. It is one of the ten most important trees in the world. The coconut palm grows in the tropics, on the shores of oceans, seas and islands. Their tall, 25-30 m trunks are usually inclined towards the sea. Almost all the islands in the Pacific Ocean are occupied by groves coconut trees. These plants are not afraid of salty...

400 million years ago, a huge part of the earth's surface of our planet was occupied by seas and oceans. The first living organisms arose in aquatic environment. They were particles of mucus. After several million years, these primitive microorganisms developed a green color. In appearance they began to resemble algae.

Climatic conditions favorably affected the growth and reproduction of algae.

Over time, the surface of the earth and the bottom of the oceans have undergone changes. New continents arose, while old ones disappeared under water. The earth's crust was actively changing. These processes led to the appearance of water on the earth's surface.

Retreating, sea water fell into crevices and depressions. They then dried up, then filled with water again. As a result, those algae that were on seabed, gradually moved to earth's surface. But since the drying process occurred very slowly, during this time they adapted to the new living conditions on earth. This process took place over a million years.

The climate at that time was very humid and warm. It facilitated the transition of plants from marine to terrestrial life. Evolution led to a more complex structure of various plants, and ancient algae also changed. They gave rise to the development of new earthly plants - psilophytes. In appearance, they resembled small plants that were located near the banks of lakes and rivers. They had a stem that was covered with small bristles. But, like algae, psilophytes did not have a root system.

Plants in a new climate

Ferns evolved from psilophytes. The psilophytes themselves ceased to exist 300 million years ago.

The humid climate and large amounts of water led to rapid spread different plants– ferns, horsetails, club mosses. The end of the Carboniferous period was marked by a change in climate: it became drier and colder. Huge ferns began to die out. The remains of dead plants rotted and turned into coal, which people then used to heat their homes.

Ferns had seeds on their leaves, which were called gymnosperms. From giant ferns came modern pines, spruces, and firs, which are called gymnosperms.

With climate change, ancient ferns have disappeared.

The cold climate destroyed their tender sprouts. They were replaced by seed ferns, which are called the first gymnosperms. These plants have adapted perfectly to the new conditions of a dry and cold climate. In this plant species, the reproduction process did not depend on water in the external environment.

130 million years ago, various shrubs and herbs arose on Earth, the seeds of which were located in the surface of the fruit. They were called angiosperms. Angiosperms have lived on our planet for 60 million years. These plants have remained virtually unchanged from then to the present day.

Without plants, our planet would be a lifeless desert. And tree leaves are small factories or chemical laboratories, where substances are transformed under the influence of sunlight and heat. Trees not only improve the composition of the air and soften its temperature. Forests have medicinal value and provide most of our food needs, as well as materials such as wood and cotton; They are also raw materials for the production of medicines.

I. What were the very first plants on earth?

Life on Earth began in the sea. And plants were the first to appear on our planet. Many of them made it to land and became completely different. But those that remained at sea remained almost unchanged. They are the most ancient, it all began with them. Without plants, life on Earth would not be possible. Only plants are able to absorb carbon dioxide and release oxygen. For this they use Sun rays. One of the first plants on earth were algae.

More than 20,000 species of algae are known. They can be anchored to rocks or the seabed using a foot-like “brace” that extends into a branch with leaves. Brown algae grows in cold waters and reaches enormous sizes. Red algae are characteristic of warm seas. Green and blue-green algae can be found in both warm and cold waters. Many useful substances used in the production of plastics, varnishes, paints, paper and even explosives are obtained from brown algae. They are used to make medicine, fertilizer, and feed for livestock. Among the peoples of Southeast Asia, seaweed is the basis of many dishes.

Algae "Floating Forest".

In the old days there were legends about the Sargasso Sea, where ships died after getting stuck in algae. But still, in some places the algae thickets are so thick that they can hold up a light boat. This is the brown algae called sargassum, after which the sea itself is named. Sargassum looks like bushes dotted with “berries” - air bubbles that allow the plant to float on the surface of the water. Unlike other large algae, sargassum does not attach to the bottom and travels along the waves in huge clusters, forming a floating forest. A myriad of mollusks, worms, and bryozoans attach to the leaves of Sargassum; crabs, shrimp, and fish hide in its thickets. Almost all of the “residents” are brownish-yellow in color, similar to sargassum, and their bodies often copy the shapes of the “leaves” of this algae. Some hide so as not to scare off their prey. So this whole community floats, never touching the shore.

II. They feed, clothe, make you happy.

1. Trees that provide food.

Coffee is one of the most popular drinks in the world.

Who gave us this wonderful drink and how? If you believe the ancient Arabian legend, then we owe the discovery of coffee. goats. One Ethiopian shepherd, according to legend, noticed that his goats, having eaten some berries from a bush, continued to graze all night, without thinking of resting. The shepherd told the wise old man about this, and he, having tasted these berries, discovered their wonderful power and invented the drink coffee.

The Ethiopians liked coffee so much that later one of the tribes, having moved to the Arabian Peninsula, took its grains with them. This was the beginning of the first coffee plantations. And this happened, as is known from ancient manuscripts, in the 9th century. Coffee was known only to the Arabs for quite a long time, but the Turks, who conquered it in the 15th-16th centuries. part of the Arab territories also appreciated the taste and wonderful properties of the drink. This is how the famous method of making Turkish coffee appeared: coffee is brewed on hot sand in special copper vessels with a handle - “Turks”.

Europeans were first introduced to coffee by an Italian who returned from Turkey. A doctor by profession, he recommended his patients to drink coffee for medicinal purposes. Venice was the first to import coffee to Europe. And in 1652 the first coffee shop was opened in England. Turkey was the monopoly supplier of coffee to Europe, but the cunning Dutch, having stolen seedlings of coffee trees from the Turks, transported them to Indonesia, where the climate was quite suitable for growing coffee.

Brazil is now the world leader in coffee production.

Coffee came to Russia thanks to Peter I.

Coffee drink is brewed from processed seeds coffee tree. This evergreen from the madder family. The white lush inflorescences of the coffee tree, located in the axils of the leaves, after pollination by insects turn into fruits - the red berries are removed from them, the seeds are polished in special drums and packed in bags. Before brewing, the coffee beans are roasted.

The birthplace of coffee is Africa. The Arabian variety is considered the highest quality and tastiest. Brazilian coffee (this is not a type, but only a place where coffee is grown), which fills all markets in the world, is much worse in quality than coffee grown in other countries.

2. Noble friends.

Cedrus are real cedars. Phenicia, Egypt, Assyria were powerful powers of antiquity. But they occupied deserted territories; there were almost no forests there. And wood is needed both for the construction of housing and for ships. The wood is strong and rot-resistant. The cedar that the ancients loved is not the cedar that grows in the taiga and is famous for its delicious nuts. Siberian pines are the namesakes of real cedars - cedrus trees.

The Phoenicians cut Cedrus for ships, the Egyptians for sarcophagi for the funeral ceremonies of their nobles, the Greeks and Romans used cedar for building temples and making furniture. Later, the crusaders began cutting down the cedrus trees. And during the First World War, the most valuable cedars with their pink wood, for lack of other fuel, were burned in locomotive furnaces. There are only 4 groves of Lebanese cedars left. True, other types of cedrus - Atlas, Cypriot and Himalayan - although very rare trees, unlike the Lebanese cedar, they are not endangered.

Lebanese cedars are majestic trees with horizontal, powerful branches. Their needles are bluish, collected in tassels. The cones are the size of a fist, dense, almost smooth, like barrels. When the seeds in them ripen, the cones do not open, but crumble, and the ground is covered with a layer of scales. The wind blows them away winged seeds and spreads it around. If goats that breed in abundance local residents, the young shoots will not be eaten; a new generation of handsome cedars can grow from them. The fame of the beauty of Lebanese cedars also reached Russia. Therefore, when the Russian pioneers saw Siberian pines, tall, majestic, with large cones, they called them cedars.

Siberian cedar is an amazing pine. The main wealth of cedar is its nuts. They contain fats, proteins, starch, vitamins B and D, and the needles contain many healing substances. Nuts contain more than 60% oil, which is superior to animal fats in many qualities and is not inferior in nutritional value to meat and eggs. Under Ivan the Terrible, these nuts were exported abroad, and under Peter I, they began to be used in Russia to prepare a healing and strengthening remedy - nut milk.

Play a huge role pine nuts in the life of animals. “Where there is no cedar,” the hunters say, “there is no sable.” The nuts are eaten by bears and chipmunks, squirrels and various birds.

Cedar resin is also healing. During the Great Patriotic War Cedar balsam helped with wounds and burns. Resin is a necessary raw material for obtaining such a valuable medicine as camphor. Resin is also needed in optical technology.

Cedar wood is also valuable - pencil sticks, musical instruments, and furniture are made from it. Turpentine and other useful products are obtained from sawdust.

III. Study of tree bark.

Norway maple

The maple tree I was watching is young. It has a tree trunk, which thickens every year, and side branches extend from it to form a crown, which consists of smaller branches and leaves. The tree is held in the soil by its roots, which absorb moisture and dissolved minerals. Therefore, the tree trunk is wider at the bottom.

If you smell the bark, the smell is bitter and astringent. In spring, the smell of the bark intensifies and becomes sweetish.

There is no hollow in my tree. But I have met trees with hollows. Various birds make their homes in the hollow.

There are no lichens, mosses or mushrooms on the maple tree that I am observing. Sometimes mushrooms form fungal roots on the roots, supplying the trees with nitrogen and minerals.

On the bark of my tree there are traces left by man: peeled bark and scratches from a knife, which over time it could heal.

IV. Why is my friend the best?

Norway maple – branch with fruits

Maple is one of the most elegant trees growing in our forests. In the spring, when the tree branches are not yet covered with leaves, the maple blooms. Its yellow-green flowers, collected in an inflorescence, are pleasing to the eye. The maple tree is no less elegant in the summer, when its crown becomes “curly.” The autumn outfit is not inferior in beauty to any other plant. The tree seems to be on fire, striking in its richness of shades of crimson and green, orange and yellow. Each leaf has its own color, and each leaf is beautiful in its own way. And they all have the same shape: round with 5-7 sharp protrusions, hence the name Norway maple. Maple is a good honey plant. Up to 10 kg of honey is obtained from one tree. Norway maple sap is very tasty. In Russia, kvass and various soft drinks were prepared from it.

The Canadian flag features a leaf from the Sugar Maple tree. Its sweet juice was used to make maple syrups, molasses, and even maple beer, which was very popular in the 19th century. Canada was the leader in the production of juice products. The maple leaf has become the national symbol of this country.

Musical instruments were made from maple wood, which was durable and light. Sports equipment is also made from maple. Pharmacists and chemists use the leaves and bark. Maple has another interesting property: it can predict the weather. From the petioles of the leaves, right next to the branch, sometimes “tears” flow drop by drop - the maple seems to be crying. This is the property of maple to get rid of excess moisture. And the “tears” of the maple depend on whether the air is dry or humid. The drier the air, the stronger the evaporation and vice versa. The air becomes humid when rain approaches. If tears appear on the maple leaves, it means it will rain in a few hours.

V. Fossil trees that remain on earth.

An ancient, ancient ginkgo tree! It appeared on earth back in the time of dinosaurs - 125 million years ago.

years ago. And since then this plant has hardly changed. Ginkgo - beautiful tree up to 30 m high, with large fan-shaped leaves. The appearance of ginkgo resembles our ordinary aspen. But it was not there! Ginkgo is a gymnosperm plant, more closely related to the spruce than to the flowering plant aspen. In spring, “catkins” appear on the branches along with the foliage. By autumn they hang on the branches large seeds, reminiscent of plums. The pulp of the seed, similar to the fruit, is actually just the seed coat. It is edible and tastes salty. The only problem is that it smells like rotten meat. This is a way to attract seed dispersing animals. Ginkgo, although it survived the dinosaurs, did not survive in the wild. This tree became a garden tree. In Japan and China, it is considered sacred and is grown near temples. Now ginkgos are also appearing on the streets of European cities. Ginkgo easily resists air pollution, diseases, and insects. Ginkgo leaves and wood contain substances that repel insects. Bookmarks made from dried ginkgo leaves will protect ancient manuscripts from bookworms. And walls covered with ginkgo shingles will not allow cockroaches or bedbugs into the house.

CONCLUSION.

What can I do for all the trees?

When I come to the forest, I will not light fires.

This may lead to fires.

I won't destroy birds' nests. Birds eat insects that harm trees. I will not break branches from trees and bushes. I will plant new seedlings in the yard and take care of them in the future.

Acid rain also causes irreparable damage: destruction of crops, flora and fauna, and destruction of buildings.

First land plants

Life originated in water. The first plants, algae, appeared here. However, at some point, land appeared that had to be populated. The pioneers among animals were lobe-finned fish. And among plants?

What did the first plants look like?

Once upon a time, our planet was inhabited by plants that had only a stem. They were attached to the ground by special outgrowths - rhizoids. These were the first plants to reach land.

Scientists call them psilophytes. This is a Latin word. Translated, it means “naked plants.” Psilophytes really looked “naked.” They only had branching stems with ball-shaped outgrowths in which spores were stored. They are very similar to the “alien plants” that are depicted in illustrations for science fiction stories.

Psilophytes became the first land plants, but they lived only in swampy areas, since they had no roots and could not get water and nutrients in the soil thickness. Scientists believe that these plants once created entire huge carpets over the bare surface of the planet. There were both tiny plants and very large ones, taller than human height.

How did scientists learn about the first plants?

Scientists learned that such plants once existed on our planet only at the beginning of the last century, in 1912, thanks to a Scottish rural doctor who was interested in geology. While examining the soil, he discovered the remains of hitherto unknown plants, which were later called rhinia, after the name of the village in which it was first found. It is believed that it was the first land plant, from which other psilophytes descended.

Ancient plants dominated the planet for millions of years, but became extinct long before humans appeared. But they left their “descendants” - they became horsetails, mosses and ferns. Some scientists believe that lower psilophytes became the ancestors of modern mosses.

The first land plants and animals

WHERE LIFE ORIGINED Life originated in water. The first plants, algae, appeared here. However, at some point, land appeared that had to be populated. The pioneers among animals were lobe-finned fish. And among plants?

WHAT THE FIRST PLANTS LOOKED Once upon a time, our planet was inhabited by plants that only had a stem. They were attached to the ground by special outgrowths - rhizoids. These were the first plants to reach land. Scientists call them psilophytes. This is a Latin word. Translated, it means “naked plants”. Psilophytes really looked “naked”. They only had branching stems with outgrowths and balls in which spores were stored. They are very similar to the “alien plants” that are depicted in illustrations for science fiction stories. Psilophytes were the first land plants, but they lived only in swampy areas, since they did not have roots and could not obtain water and nutrients from the soil. Scientists believe that these plants once created entire huge carpets over the bare surface of the planet. There were both tiny plants and very large ones, taller than human height.

THE FIRST ANIMALS ON EARTH The oldest traces of animal life on Earth date back a billion years, but the oldest fossils of animals themselves are approximately 600 million years old, dating back to the Vendian period. The first animals that appeared on Earth as a result of evolution were microscopically small and soft-bodied. They lived on the seabed or in the bottom mud. Such creatures could hardly petrify, and the only clue to the mystery of their existence is indirect traces, such as the remains of holes or passages. But despite their tiny size, these most ancient animals were resilient and gave rise to the first known animals on Earth - the Ediacaran fauna.

The evolution of life on Earth began with the appearance of the first living creature - about 3.7 billion years ago - and continues to this day. The similarities between all organisms indicate the presence common ancestor, from which all other living beings originate.

ALL

psilophytes (Psilophyta), the most ancient and primitive extinct group (division) of higher plants. They were characterized by the apical arrangement of sporangia (See Sporangium) and uniform sporosity, the absence of roots and leaves, dichotomous or dichopodial (pseudomonopodial) branching, and a primitive anatomical structure. The conducting system is a typical Protostele. The protoxylem was located in the center of the xylem; the metaxylem consisted of tracheids with ringed or (less commonly) scalariform thickenings. There were no supporting tissues. R. did not yet have the ability for secondary growth (they had only apical meristems (See Meristem). Sporangia are primitive, from spherical (about 1 mm in diameter) to oblong-cylindrical (up to 12 mm long), thick-walled. R.'s gametophytes are not reliably known (some authors consider horizontal rhizome-like organs - the so-called rhizomoids - to be gametophytes).

R. grew in damp and swampy places, as well as in shallow coastal waters. The R. division includes one class, the rhyniopsida (Rhyniopsida), with two orders: Rhyniales (families Cooksoniaceae, Rhyniaceae, Hedeiaceae) and Psilophytales (family Psilophytaceae). The order Rhyniales is characterized by dichotomous branching and a thin, poorly developed stele. Xylem of tracheids with ring-shaped thickenings. The oldest representative of R. is the genus Cooksonia, originally discovered in Wales in deposits of the late Silurian period (about 400 million years ago). The most fully studied Lower Devonian genera are rhinia and partly horneophyte, in which the rhizomoid (stems extending upward from it, numerous rhizoids extending downward) was dissected into clearly located tuberous segments, devoid of conducting tissues and consisting entirely of parenchyma cells. It is believed that in the process of evolution, rhizomoids of R. gave rise to roots. In both genera, the sporangial wall was multilayered, covered with a cuticle (See Cuticle). The horneophyte is characterized by a peculiar spore-bearing cavity, which forms a dome that vault-like covers the central column of sterile tissue, which is a continuation of the phloem of the stem. In this way, the horneophyte resembles modern Sphagnum. The rhinium family also includes the genus Teniokrada, many species of which formed underwater thickets in the Middle and Upper Devonian. The Lower Devonian genera Hedea and Yaravia are sometimes classified as a separate family of Hedeidae. The Lower Devonian genus Sciadophyte, usually classified as a separate family Sciadophyte, is a small plant consisting of a rosette of simple or weakly dichotomized thin stems with a stele. The order Psilophytales is characterized by dichopodial branching and a more strongly developed stele. In the most famous genus, psilophyte (from Lower Devonian deposits in Eastern Canada), unequally developed branches formed a false main axis of dichopodium with thinner lateral branches: the stem was surrounded by cutinized epidermis with stomata; the surface of the stem was bare or covered with spines 2-2.5 mm long, the ends of which expanded disc-shaped, which probably indicated their secretory role. The sporangia opened with a longitudinal crack. The Lower Devonian genera trimerophyte and pertika are close to psilophyte.

The study of the structure of R. and their evolutionary relationships has great importance for the evolutionary morphology and phylogeny of higher plants. Apparently, the original organ of the sporophyte of higher plants was a dichotomously branching stem with apical sporangia; roots and leaves evolved later than the sporangium and stem. There is every reason to consider R. the original ancestral group from which bryophytes, lycophytes, horsetails and ferns descended. According to another point of view, bryophytes and lycophytes have only common origin with R.

Lit.: Fundamentals of paleontology. Algae, bryophytes, psilophytes, lycophytes, arthropods, ferns, M., 1963; Traite de paleobotanique, t. 2, Bryophyta. Psilophyta. Lycophyta, P., 1967.

A. L. Takhtadzhyan.

Planet Earth was formed more than 4.5 billion years ago. The first single-celled life forms appeared perhaps about 3 billion years ago. At first it was bacteria. They are classified as prokaryotes because they do not have a cell nucleus. Eukaryotic (those with nuclei in cells) organisms appeared later.

Plants are eukaryotes capable of photosynthesis. In the process of evolution, photosynthesis appeared earlier than eukaryotes. At that time it existed in some bacteria. These were blue-green bacteria (cyanobacteria). Some of them have survived to this day.

According to the most common hypothesis of evolution, plant cell formed by the entry into a heterotrophic eukaryotic cell of a photosynthetic bacterium that was not digested. Further, the process of evolution led to the appearance of a single-celled eukaryotic photosynthetic organism with chloroplasts (their predecessors). This is how unicellular algae appeared.

The next stage in the evolution of plants was the emergence of multicellular algae. They reached great diversity and lived exclusively in water.

The surface of the Earth did not remain unchanged. Where Earth's crust rose, land gradually appeared. Living organisms had to adapt to new conditions. Some ancient algae were gradually able to adapt to a terrestrial lifestyle. In the process of evolution, their structure became more complex, tissues appeared, primarily integumentary and conductive.

The first land plants are considered to be psilophytes, which appeared about 400 million years ago. They have not survived to this day.

Further evolution of plants, associated with the complication of their structure, took place on land.

During the time of the psilophytes, the climate was warm and humid. Psilophytes grew near bodies of water. They had rhizoids (like roots), with which they anchored themselves in the soil and absorbed water. However, they did not have true vegetative organs (roots, stems and leaves). The movement of water and organic substances throughout the plant was ensured by the emerging conductive tissue.

Later, ferns and mosses evolved from psilophytes. These plants have more complex structure, they have stems and leaves, they are better adapted to living on land. However, just like psilophytes, they remained dependent on water. During sexual reproduction, in order for the sperm to reach the egg, they need water. Therefore, they could not “go” far from wet habitats.

During the Carboniferous period (approximately 300 million years ago), when the climate was humid, ferns reached their dawn, and many of their tree forms grew on the planet. Later, dying off, it was they who formed coal deposits.

When the climate on Earth began to become colder and drier, ferns began to die out en masse. But some of their species before this gave rise to the so-called seed ferns, which in fact were already gymnosperms. In the subsequent evolution of plants, seed ferns became extinct, giving rise to other gymnosperms. Later, more advanced gymnosperms appeared - conifers.

The first plants on Earth

Pollination occurred with the help of wind. Instead of spermatozoa (mobile forms), they formed sperm (stationary forms), which were delivered to the egg special education pollen grain. In addition, gymnosperms produced not spores, but seeds containing a supply of nutrients.

The further evolution of plants was marked by the appearance of angiosperms (flowering plants). This happened about 130 million years ago. And about 60 million years ago they began to dominate the Earth. Compared to gymnosperms, flowering plants better adapted for life on land. You could say they began to take advantage of opportunities more environment. So their pollination began to occur not only with the help of the wind, but also with the help of insects. This increased pollination efficiency. Angiosperm seeds are found in fruits, which allow them to spread more efficiently. In addition, flowering plants have more complex tissue structure, for example, in a conducting system.

Currently, angiosperms are the most numerous group of plants in terms of the number of species.

Main article: Ferns

Rhiniophytes is an extinct group of plants. Some scientists consider them the ancestors of mosses, ferns, horsetails and mosses. Others suggest that rhyniophytes colonized land at the same time as mosses.

The first land plants—rhiniophytes—appeared about 400 million years ago. Their body consisted of green twigs. Each branch branched, dividing into two parts. The cells of the twigs contained chlorophyll and photosynthesis occurred. Material from the site http://wikiwhat.ru

Rhinophytes grew in moist places. They were attached to the soil by rhizoids - outgrowths on the surface of horizontally located twigs.

First land plants

At the ends of the branches there were spore-bearing parts in which spores ripened. Conductive and mechanical tissues have already begun to form in rhinophytes. In the process of evolution, due to the occurrence of hereditary changes and natural selection, integumentary tissue with stomata was formed on the surface of the branches of rhinophytes with stomata regulating the evaporation of water.

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On this page there is material on the following topics:

• Conductive integumentary and mechanical tissues in rhinophyte and ferns

• Life cycle of rhionophytes diagram

• Rhinophytes story answer

• Post the first land plant

• When and from what group of algae did the first reniophytes appear?

Origin and taxonomy of higher plants.

Higher plants probably evolved from some kind of algae. This is evidenced by the fact that in geological history of the plant world, higher plants were preceded by algae. This assumption is supported by the following facts: the similarity of the most ancient extinct group of higher plants - rhiniophytes - with algae, the very similar nature of their branching; similarity in the alternation of generations of higher plants and many algae; the presence of flagella and the ability for independent swimming in male germ cells of many higher plants; similarities in the structure and function of chloroplasts.

It is believed that higher plants most likely originated from green algae, freshwater or brackish water. They had multicellular gametangia, an isomorphic alternation of generations in the development cycle.

The first land plants found in fossil form were rhiniophytes(rhinia, hornea, horneophyton, sporogonytes, psilophyte, etc.).

After reaching land, higher plants developed in two main directions and formed two large evolutionary branches - haploid and diploid.

The haploid branch of the evolution of higher plants is represented by the bryophyta division. In the development cycle of mosses, the gametophyte, the sexual generation (the plant itself), predominates, and the sporophyte, the asexual generation, is reduced and is represented by a sporogon in the form of a box on a stalk.

The second evolutionary branch of higher plants is represented by all other higher plants.

The sporophyte in terrestrial conditions turned out to be more viable and adapted to a variety of environmental conditions. This group of plants conquered land more successfully.

Currently, higher plants number over 300,000 species. They dominate the Earth, inhabiting it from the Arctic territories to the equator, from the humid tropics to dry deserts. They form Various types vegetation - forests, meadows, swamps, fill reservoirs. Many of them reach gigantic sizes.

Taxonomy of higher plants is a branch of botany that develops natural classification higher plants based on the study and identification of taxonomic units, establishes family ties between them in their historical development. The most important concepts of systematics are taxonomic (systematic) categories and taxa.

Evolution of plants

According to the rules of botanical nomenclature, the main taxonomic categories are: species (species), genus (genus), family (familia), order (ordo), class (classis), department (devisio), kingdom (regnum). If necessary, intermediate categories can be used, for example, subspecies, subgenus, subfamilia, superordo, superregnum.

For species starting from 1753 - the date of publication of the book K. Linnaeus"Plant species" – accepted binomial names, consisting of two Latin words. The first designates the genus to which the species belongs, the second - the specific epithet: for example, sticky alder - Alnus glutinosa.

For plant families the ending is aceae, for orders - ales, for subclasses - idae, for classes - psida, for divisions - phyta. The standard uninominal name is based on the name of a genus included in this family, order, class, etc.

Modern science about the organic world divides living organisms into two superkingdoms: prenuclear organisms (Procariota) and nuclear organisms (Eucariota). The superkingdom of prenuclear organisms is represented by one kingdom - shotworts (Mychota) with two subkingdoms: bacteria (Bacteriobionta) and cyanotea, or blue-green algae (Cyanobionta).

The superkingdom of nuclear organisms includes three kingdoms: animals (Animalia), fungi (Mycetalia, Fungi, or Mycota) and plants (Vegetabilia, or Plantae).

The animal kingdom is divided into two subkingdoms: protozoa and multicellular animals (Metazoa).

The fungal kingdom is divided into two subkingdoms: lower fungi (Myxobionta) and higher fungi (Mycobionta).

The plant kingdom includes three subkingdoms: scarlet(Rhodobionta), real seaweed(Phycobionta) and higher plants(Embryobionta).