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, the plant cell was 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 the earth's crust rose, land gradually emerged. 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 a more complex structure, they have stems and leaves, and 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 reproduction of gymnosperms no longer depended on the presence of liquid water. Pollination occurred with the help of wind. Instead of spermatozoa (mobile forms), they formed spermatozoa (stationary forms), which were delivered to the egg by special formations of pollen grains. 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 are better adapted to life on land. We can say that they began to use the possibilities of the environment more. 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 a more complex tissue structure, for example, in the conducting system.

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

Monocarpic and polycarpic plants. Annuals bloom and bear fruit once in a lifetime, after which they die completely. They behave like monocarpics - once fruiting plants. Most perennial herbs, woody and semi-woody plants are polycarpic, that is, they bear fruit many times during their life.

But not all perennial plants are capable of repeated flowering and fruiting. Among perennial herbs and even among woody plants there are also monocarpics that die off entirely after the first fruiting. Unlike annuals, the vegetative phase of their life lasts several, sometimes many (50-60) years. Typical examples include some types of palm trees ( Corypha), agaves, some types of bamboos. Perennial herbaceous monocarpics include many Asteraceae (for example, some types of thistles and thistles) and umbelliferous plants (angelica, angelica, caraway, and caraway). These rosette-shaped plants live 5-10-12 years, after which they bloom and die. In cultivation, these same plants (for example, caraway) usually behave like biennials: in the first year they go through a vegetative rosette phase, and in the second year they bloom. Biennials, including cultivated ones - cabbage, carrots, beets - are also monocarpics.

Large and small life cycle. In the course of individual development - ontogeny- plants experience age-related physiological changes from the embryonic state to the sexually mature state, and then to ripe old age. Morphologically, these age-related changes are expressed in a consistent change in the structure of root and shoot systems, in the ratio of vegetative and generative organs, in the ability for vegetative reproduction at certain stages of ontogenesis, and finally, simply in body size. However, determining the absolute age of plants is not easy, since they are characterized by a constant change of organs. Older parts die and collapse. The age of a perennial herbaceous plant, calculated from the annual growth of the rhizome in length or from the annual rings of wood in a cross section, usually does not reflect its true age, but corresponds only to the age of the youngest living part . An individual that has arisen sexually (from a seed) can sooner or later lose its integrity and break up into several daughter viable individuals, i.e., form a clone. Each new individual - part of a clone (particulate) - bears its mark to one degree or another age of the maternal seed individual, but it may also turn out to be significantly rejuvenated (individuals from dormant rhizome buds, root suckers). Daughter individuals go through their own life cycle, which no longer begins from the moment of seed germination, but from the moment of separation from the mother plant. In herbaceous plants that quickly replace shoots, each shoot goes through a life cycle from the development of a bud to flowering, fruiting and death of the aerial part (“small cycle”). Therefore, there is a need to highlight the concept of “large life cycle,” which means the entire ontogenesis of a plant, from the emergence of an embryo in a seed to the natural death of the individual and all its vegetative descendants, i.e., parts of the clone, if vegetative propagation takes place. A large life cycle consists of a set of small cycles of different scales (individual shoots, partial bushes, etc.). In vegetatively immobile and vegetatively inactive plants, the boundaries of the individual and the clone are more compact, in vegetatively mobile plants they are very vague and in the later stages of a large life cycle are often indefinable.

Age groups of perennial polycarpic plants. Each individual at a certain moment in its development can be characterized in two ways: 1) calendar age, which represents the period of time from the moment of the appearance of the individual until the moment of observation; 2) a set of age characteristics characterizing the stage of ontogenetic development of an individual, its age level.

Currently, when determining the stage of ontogenetic development of an individual, the term " age condition". Synonyms of this term are “physiological age”, “biological age” and “age”.

The age state of an individual can be defined as its physiological and biochemical state, reflecting the stage of individual development that the individual is going through at the time of observation. The idea of ​​the age state as a stage of individual development of an individual formed the basis of numerous periodizations of ontogenesis.

Age-related changes are manifested in changes in both the structure (morph) and functions of the body. Indicators of age-related conditions in coenopopulation studies are mainly morphological changes associated with anatomical, physiological, and biochemical changes.

The age state is always associated with the calendar age of the plant, since the sequence of ontogenetic processes occurs over time.

The long life cycle is usually divided into the following age states (according to T.A. Rabotnov’s classification, with some modifications):

1 From lat. latens- hidden, invisible.

2 From lat. virginitas- virginity.

3 From lat. juvenilis- youthful.

4 From lat. immaturus- immature.

5 From Lat. senilis- senile.

This classification of age-related conditions applies to both polycarpics and annual and perennial monocarpics. In polycarpics, all of the age-related conditions listed above are usually distinguished; in some cases, the post-generative period is not expressed (some tree species). In monocarpics, all age states are distinguished up to the generative period; the generative period is not subdivided.

Plants are assigned to a particular age state based on a set of qualitative characteristics. The most significant of them are the following: method of nutrition (connection with the seed); the presence of embryonic, juvenile or adult structures and their quantitative ratios in an individual; the ability of individuals to reproduce by seed or vegetative propagation, the ratio and intensity of these processes; the relationship between the processes of new formation and death in an individual, the degree of formation of the main characteristics of the biomorph in an individual. “Life form,” “biomorph,” is defined by adult individuals, usually in the g 2 state.

Seasonal phenomena in plants. One of the essential signs of a life form is the seasonal behavior of the plant. In periodically dry or cold climates, seasonal phenomena are expressed in a number of morphological and anatomical changes. One of the most famous and conspicuous seasonal processes is leaf fall in woody plants, which is replaced "Branchfall" in leafless xerophytes of deserts, for example, in saxaul.

In herbaceous plants, leaf fall is rarely observed (for example, stinging nettle, impatience). Typically, entirely elongated vertical aboveground shoots of grasses die off, and on ground creeping and rosette shoots the leaves die off and collapse gradually without falling off. Dead shoots of grasses are also destroyed gradually, going under the snow or rising above the snow cover (in the latter case, sometimes in winter the dispersal of seeds that remained in fruits or fruits until winter continues, for example, in wormwood and other Asteraceae).

In spring, all perennial plants, woody and herbaceous, develop buds and grow new annual or elementary shoots. At the same time, the work of the cambium is renewed and enhanced in perennial stems and roots. At the same time, reserve nutrients are actively mobilized from the parenchymal tissues of storage organs (in particular, in trees this causes spring sap flow). During the entire growing season, perennial plants form and mature new buds of renewal, the formation of new vegetative and often generative organs in them. The accumulation of reserve nutrients increases with the onset of winter or drought; specialized storage organs are formed - tubers, bulbs, etc. At the beginning of a new growing season, these substances are intensively spent on the intensive growth of new shoots and roots and the resumption of cambium function. In many perennial grasses, especially meadows, in addition to the spring development of buds, summer-autumn shoot formation is also well expressed, i.e. formation of the second generation of shoots during the growing season. In meadow grasses (fescue, bluegrass, etc.), the regrowth of the second generation of shoots is strongly stimulated by mowing. The so-called “remnant” is used for the second cutting or feeding to livestock.

Flowering frequency. The flowering period for different plants occurs at certain times. In particular, early flowering species deserve special mention; some of them bloom immediately after snowfall or even when there is noticeable residual snow cover. Early spring flowering plants include many of the tree species and shrubs of the middle zone: alder (near Moscow it blooms first, in March or early April), hazel, willows, aspen, poplars. All of them bloom before the leaves bloom, which promotes wind pollination, and willows are pollinated by newly awakened bees. A little later, simultaneously with the leaves blooming, birch, maple, elm, ash and, finally, oak bloom, whose leaves unfold later than most other deciduous species of the mixed Central Russian forest. Early flowering herbaceous plants are characteristic of deciduous forests (lungwort, corydalis, anemone, guillemot, spleenwort, scilla, liverwort; pollinated by the first insects before shading by the tree canopy); in the forest zone in open areas the only early flowering species is coltsfoot. Some species of sphagnum bogs (cassandra, or bog myrtle) bloom early. In steppes and semi-deserts, many plants bloom early, using spring moisture (tulips, hyacinths, bird's-eye, adonis, etc.).

The duration of flowering of different plants is also different. Some plants bloom quickly, within a few days; others bloom for weeks; third - almost the entire season, from spring to autumn, due to the appearance of new flowers and inflorescences on the same shoot (forget-me-not, cinquefoil) or new flowering shoots (turfgrass, buttercup). Some plants that have limited flowering periods in spring or early summer can bloom again in the event of a long warm and humid autumn (tenacious, buttercups, strawberries, etc.).

Growing season duration. According to the duration of the growing season (meaning the presence of green assimilating leaves), plants can be divided into evergreen(with green leaves all year round; leaves live for more than one astronomical year - conifers, lingonberries, hoofweed), summer-winter green(all year round with green leaves, but individual leaves live for less than a year and are replaced - sorrel, mantle, strawberry), summer green(deciduous or with shoots that completely die off for the winter), winter green(they lose leaves or shoots in the summer, and vegetate in the fall and winter - some plants have a Mediterranean climate with severe summer drought and mild, warm winters). Among summer greens in a broad sense, we can especially highlight ephemera spring, and sometimes autumn (annuals that grow for a very short period of time - from 2-3 weeks to 1-2 months), and ephemeroids (perennials that lose their entire above-ground part very quickly, by the beginning of summer - desert and steppe tulips, tuberous and bulbous forest ephemeroids - corydalis, anemone).

The diversity of plants in terms of growing season and flowering in the same community contributes to the most complete use of the entire growing season as a whole, i.e. different groups are adapted to different, seasonally changing lighting conditions (the establishment and disappearance of shading by the canopy of trees in a deciduous forest), humidity, temperature, different pollination factors, etc.

Adaptations of higher plants to heterotrophic nutrition. For higher plants, autotrophic nutrition is common and normal - photosynthesis in combination with soil nutrition, which supplies the plant with all the necessary mineral elements, including nitrogen. The method of nutrition is reflected in the general appearance of a higher plant with its developed system of leafy green shoots and a root system intensively spreading in the soil. True heterotrophic organisms capable of feeding on dead organic remains (saprotrophs) are found only among fungi and bacteria. However, higher plants also have a number of adaptations to the use of not only mineral, but also organic substances of the substrate. This is especially important in conditions of almost complete absence of mineral salts, for example, with an epiphytic lifestyle or when living on very poor leached soils, on sphagnum peat bogs. In most cases, flowering plants living on such substrates, while remaining green and capable of photosynthesis, receive additional nitrogen nutrition due to symbiosis with fungi or bacteria that settle in their roots (mycorrhiza, bacteriorrhiza). This - symbiotrophic plants.

Some autotrophic plants, which usually live in swamps (in the tropical and partly temperate zones), compensate for the lack of nitrogen in the substrate with additional nutrition from small animals, in particular insects, whose bodies are digested with the help of enzymes secreted by special glands on the leaves insectivores, or predatory, plants. Typically, the ability for this type of feeding is accompanied by the formation of a variety of hunting devices.

The sundew, common in sphagnum bogs, has leaves covered with reddish glandular hairs that secrete droplets of a sticky shiny secretion at the tips. Small insects stick to the leaf and with their movements irritate other glandular hairs of the leaf, which slowly bend towards it and tightly surround it with their glands. Dissolution and absorption of food occur over several days, after which the hairs straighten and the leaf can again catch prey.

The hunting apparatus of the Venus flytrap, which lives in the peat bogs of eastern North America, has a complex structure . The leaves have sensitive bristles that cause the two blade blades to snap shut when touched by an insect.

Trap leaves of Nepenthes , climbing plants of coastal tropical thickets of the Indo-Malayan region, have a long petiole, the lower part of which is wide, lamellar, green (photosynthetic); the middle one is narrowed, stem-like, curly (it wraps around the support), and the top one is turned into a variegated jug, covered on top with a lid - a leaf blade. A sugary liquid secretes along the edge of the jug, attracting insects. Once in the jug, the insect slides along the smooth inner wall to its bottom, where the digestive liquid is located.

In stagnant bodies of water we usually have a submerged floating bladderwort plant. It has no roots; the leaves are dissected into narrow thread-like lobules, at the ends of which there are trapping vesicles with a valve that opens inward. Small insects or crustaceans cannot get out of the bubble and are digested there.

TICKET#1

The relationship between plastic and energy metabolism.

Metabolism- the main sign of living things. The constant exchange of substances between every living organism and its environment: the absorption of some substances and the release of others. The absorption of inorganic substances by plants and some bacteria from the environment and the use of sunlight energy to create organic substances from them. Obtaining from the environment by animals, fungi, a significant group of bacteria, as well as humans, organic substances and the solar energy stored in them.

The essence of exchange. The main thing in metabolism and energy conversion is the processes occurring in the cell: the entry of substances into the cell from the environment, their transformation with the help of energy and the creation from them (synthesis) of certain cell substances, then the oxidation of organic substances to inorganic ones with the release of energy. Plastic metabolism is the process of assimilation by the body of substances obtained from the environment and accumulation of energy. Energy metabolism is the oxidation of organic substances in most organisms and their breakdown into inorganic substances - carbon dioxide and water with the release of energy. The importance of energy metabolism is the provision of energy to all vital processes of the body. The relationship between plastic and energy metabolism. Release of metabolic end products (water, carbon dioxide and other compounds) into the environment.

The meaning of metabolism: providing the body with the substances and energy it needs to build its body, freeing it from harmful waste products. The similarity of plastic and energy metabolism in animals and humans.

Increasing complexity of plant organization in the process of evolution. Reasons for evolution.

Reasons for plant evolution: variability and heredity of the organism, the struggle for existence in nature and natural selection - their discovery in the middle of the 19th century by the English scientist Charles Darwin. The occurrence of changes in plants during life, the transmission of some of them to offspring by inheritance. Preservation by natural selection of changes that are useful under certain conditions, and their transmission to offspring during the process of reproduction. The role of natural selection, which occurs constantly over millions of years, in the emergence of new plant species.

Stages of plant evolution. The very first most simply organized organisms are unicellular algae. The appearance as a result of variability and heredity of multicellular algae, the preservation of this useful feature by natural selection. The origin of more complex plants - psilophytes - from ancient algae, and from them - mosses and ferns. The appearance of organs in ferns - stems, leaves and roots, and a more developed conducting system. Origin from ancient ferns due to heredity and variability, the action of natural selection of ancient gymnosperms, which had a seed. Unlike a spore (one specialized cell from which a new plant develops), a seed is a multicellular formation, has a formed embryo with a supply of nutrients, covered with a dense skin. The likelihood of a new plant emerging from a seed is much greater than from a spore that has a small supply of nutrients. Origin from ancient gymnosperms of more complex plants - angiosperms, which developed flowers and fruits. The role of the fruit is to protect the seed from unfavorable conditions. Distribution of fruits. The complication of the structure of plants from algae to angiosperms over many millions of years due to the ability of plants to change, to transmit changes by inheritance, and to the action of natural selection.

Ticket#2

1. Respiration of organisms, its essence and meaning.

1. The essence of respiration is the oxidation of organic substances in cells with the release

energy necessary for life processes. Receipt of necessary

for breathing oxygen into the body cells of plants and animals: in plants through

stomata, lentils, cracks in tree bark; in animals - through the surface

body (for example, in an earthworm), through the respiratory organs (trachea in insects,

gills in fish, lungs in terrestrial vertebrates and humans). Oxygen transport

blood and its entry into the cells of various tissues and organs in many animals

and man.

2. Participation of oxygen in the oxidation of organic substances

to inorganic, releasing energy obtained from food,

its use in all life processes. Oxygen absorption

body and removal of carbon dioxide from it through the surface of the body or

respiratory organs - gas exchange.

3. The relationship between the structure and functions of the respiratory organs.

The adaptability of the respiratory organs, for example in animals and humans, to perform

functions of oxygen absorption and carbon dioxide release: increase in volume

lungs of humans and mammals due to the huge number of pulmonary

bubbles penetrated by capillaries, increasing contact surface

blood with air, thereby increasing the intensity of gas exchange.

The adaptability of the structure of the walls of the respiratory tract to air movement during

inhalation and exhalation, cleansing it of dust (ciliated epithelium, the presence of cartilage).

4. Gas exchange in the lungs. Exchange of gases in the body by

diffusion. Entry into the lungs through the arteries of the pulmonary circulation, venous

carbon dioxide. Penetration of oxygen from the lungs into the plasma of venous blood

bubbles and capillaries by diffusion through their thin walls, and then into

red blood cells. Formation of a weak compound of oxygen with hemoglobin -

oxyhemoglobin. Constant saturation of blood plasma with oxygen and simultaneous

release of carbon dioxide from the blood into the air of the lungs, conversion of venous blood

into the arterial

5. Gas exchange in tissues. Admission in a large circle

arterial blood circulation, saturated with oxygen and poor in carbon dioxide

blood in tissue. The supply of oxygen to the intercellular substance and body cells, where

its concentration is significantly lower than in the blood. Simultaneous blood saturation

carbon dioxide, converting it from arterial to venous. Transport

carbon dioxide, which forms a weak compound with hemoglobin, into the lungs.

2. The plant kingdom, their structure and life activity. Role in nature and life

1. Characteristics of the plant kingdom. Variety of plants: algae, mosses,

various environmental conditions. General characteristics of plants: they grow throughout their lives, practically

do not move from one place to another. The presence of a durable cell shell made of

fiber, which gives it its shape, and vacuoles filled with cell sap.

The main feature of plants is the presence of plastids in their cells, among which

The leading role belongs to chloroplasts containing the green pigment - chlorophyll.

The method of nutrition is autotrophic: plants independently create organic

substances from inorganic using solar energy (photosynthesis).

2. The role of plants in the biosphere. Using solar

energy for the creation of organic substances during photosynthesis and release during

This oxygen is necessary for the respiration of all living organisms. Plants -

producers of organic matter, providing for themselves, as well as

animals, fungi, most bacteria and human food and the food contained in it

energy. The role of plants in the cycle of carbon dioxide and oxygen in the atmosphere.

The emergence of unicellular and multicellular algae, the emergence of photosynthesis: the emergence of plants on land (psilophytes, mosses, ferns, gymnosperms, angiosperms).

The development of the plant world took place in 2 stages and is associated with the appearance of lower and higher plants. According to the new taxonomy, algae are classified as lower (and previously included bacteria, fungi and lichens. Now they are separated into independent kingdoms), and mosses, pteridophytes, gymnosperms and angiosperms are classified as higher.

In the evolution of lower organisms, two periods are distinguished, which differ significantly in the organization of the cell. During period 1, organisms similar to bacteria and blue-green algae dominated. The cells of these life forms did not have typical organelles (mitochondiria, chloroplasts, Golgi apparatus, etc.). The cell nucleus was not limited by the nuclear membrane (this is a prokaryotic type of cellular organization). Period 2 was associated with the transition of lower plants (algae) to an autotrophic type of nutrition and with the formation of a cell with all the typical organelles (this is a eukaryotic type of cellular organization, which was preserved at subsequent stages of development of the plant and animal world). This period can be called the period of dominance of green algae, unicellular, colonial and multicellular. The simplest of multicellular organisms are filamentous algae (ulotrix), which do not have any branching in their body. Their body is a long chain consisting of individual cells. Other multicellular algae are dissected by a large number of outgrowths, so their body is branched (in Chara, in Fucus).

Multicellular algae, due to their autotrophic (photosynthetic) activity, developed in the direction of increasing their body surface for better absorption of nutrients from the aquatic environment and solar energy. Algae have a more progressive form of reproduction - sexual reproduction, in which a new generation begins with a diploid (2n) zygote, combining the heredity of 2 parental forms.

The 2nd evolutionary stage of plant development must be associated with their gradual transition from an aquatic to a terrestrial lifestyle. The primary terrestrial organisms turned out to be psilophytes, which were preserved as fossil remains in Silurian and Devonian deposits. The structure of these plants is more complex compared to algae: a) they had special organs of attachment to the substrate - rhizoids; b) stem-like organs with wood surrounded by phloem; c) rudiments of conducting tissues; d) epidermis with stomata.

Starting with psilophytes, it is necessary to trace 2 lines of evolution of higher plants, one of which is represented by bryophytes, and the second by ferns, gymnosperms and angiosperms.

The main thing that characterizes bryophytes is the predominance of the gametophyte over the sporophyte in their individual development cycle. A gametophyte is an entire green plant capable of self-feeding. The sporophyte is represented by a capsule (cuckoo flax) and is completely dependent on the gametophyte for its nutrition. The dominance of the moisture-loving gametophyte in mosses under the conditions of an air-terrestrial lifestyle turned out to be impractical, so mosses became a special branch of the evolution of higher plants and have not yet given rise to perfect groups of plants. This was also facilitated by the fact that the gametophyte, compared to the sporophyte, had poor heredity (haploid (1n) set of chromosomes). This line in the evolution of higher plants is called gametophytic.

The second line of evolution on the path from psilophytes to angiosperms is sporophytic, because in ferns, gymnosperms and angiosperms the sporophyte dominates in the cycle of individual plant development. It is a plant with a root, stem, leaves, sporulation organs (in ferns) or fruiting organs (in angiosperms). Sporophyte cells have a diploid set of chromosomes, because they develop from a diploid zygote. The gametophyte is greatly reduced and is adapted only for the formation of male and female germ cells. In flowering plants, the female gametophyte is represented by the embryo sac, which contains the egg. The male gametophyte is formed when pollen germinates. It consists of one vegetative and one generative cell. When pollen germinates, 2 sperm arise from the generative cell. These 2 male reproductive cells are involved in double fertilization in angiosperms. The fertilized egg gives rise to a new generation of the plant - the sporophyte. The progress of angiosperms is due to the improvement of the reproductive function.

Plant groups Signs of increasing complexity of plant organization (aromorphoses) 1. Algae The appearance of chlorophyll, the emergence of photosynthesis, multicellularity. 2. Psilophytes as a transitional form Special organs of attachment to the substrate are rhizoids; stem organs with rudiments of conducting tissues; epidermis with stomata. 3. Mosses The appearance of leaves and stems, tissues that provide the possibility of life in a terrestrial environment. 4. Ferns The appearance of true roots, and in the stem - tissues that ensure the conduction of water absorbed by the roots from the soil. 5. Gymnosperms The appearance of the seed is internal fertilization, the development of the embryo inside the ovule. 6. Angiosperms The appearance of a flower, the development of seeds inside the fruit. Diversity of roots, stems, leaves in structure and functions. Development of a conducting system that ensures the rapid movement of substances in the plant.

Conclusions:

1. The study of the geological past of the Earth, the structure and composition of the core and all shells, spacecraft flights to the Moon, Venus, and the study of stars brings a person closer to understanding the stages of development of our planet and life on it.
2. The process of evolution was natural.
3. The plant world is diverse, this diversity is the result of its development over a long time. The reason for its development is not divine power, but the change and complication of the structure of plants under the influence of changing environmental conditions.

Scientific evidence: cellular structure of plants, the beginning of development from a single fertilized cell, the need for water for life processes, finding prints of various plants, the presence of “living” fossils, the extinction of some species and the formation of new ones.

The structure and vital activity of algae.

Algae are photosynthetic autotrophic eukaryotic organisms.

There are about 30 thousand species of different algae. There are divisions of Green, Red, Brown algae, etc. Algae are unicellular, multicellular And colonial.
Body of multicellular algae ( thallus ) consists of similar cells and is not divided into organs and tissues. The forms of the thallus are very diverse: monadic, amoeboid, filamentous, lamellar, etc. Chloroplasts of algae are called chromatophores. Many mobile algae have a light-sensitive eye ( stigma ), due to which these algae have phototaxis - the ability to move towards the light.
Algae live mainly in water, but a large number of species settle on land in moist habitats (on the soil surface, stones, tree bark).
Algae propagation. Algae can reproduce asexually and sexually. TO asexual applies vegetative propagation(division of the thallus into parts in multicellular organisms, division of cells into two in unicellular organisms, disintegration of colonies in colonial forms) and sporulation(formation of motile or immobile spores in sporangia). Sexual reproduction involves the formation of gametes and their subsequent fusion to form a zygote, as well as simply the fusion of two single-celled algae with each other, or through conjugation. During sexual reproduction, the gametophyte predominates in the life cycle of green algae, while the sporophyte predominates in the life cycle of brown algae.
Green algae distributed mainly in fresh waters (about 13 thousand species). In addition to the aquatic environment, some species live on the surface of the soil, etc., and also enter into symbiotic relationships with fungi. Distinctive features: 1) content in chloroplasts chlorophyll A And b , predominant over other pigments; 2) the main storage product is starch ; 3) the cell wall is formed by cellulose. There are green algae unicellular(chlamydomonas, chlorella), multicellular(ulotrix, spirogyra) and colonial(volvox).
Red algae distributed mainly in warm waters of seas and oceans (about 4 thousand species). Almost all red algae are multicellular. Distinctive features: 1) content in chloroplasts chlorophyll a And d , as well as pigments from bright red to almost black in color, which allows them to perceive the sun's rays from that part of the spectrum that penetrate deeper into the water column; 2) the main storage product is purple starch , similar in structure to glycogen; 3) there are no moving stages in the life cycle. Red algae include porphyra, bangia, nemalion, etc.
Brown algae distributed mainly in temperate or cold waters of seas and oceans (about 1.5 thousand species). All brown algae are multicellular. Distinctive features: 1) content in chloroplasts chlorophyll a And c and other pigments; 2) the main storage product is laminarin ; 3) there are moving stages in the life cycle. Brown algae include kelp (seaweed), fucus, sargassum, macrocystis, etc.
The meaning of algae. Algae are an important component of the aquatic community. In the waters of the world's oceans, algae are the main producers of organic substances. In addition, they release oxygen necessary for animals and plants to breathe. Algae living on the soil surface are involved in soil formation. Algae played a huge role in the history of the Earth, enriching the atmosphere with oxygen. Algae are also widely used by humans: for food and livestock feed (rich in vitamins, iodine and bromine salts), for the production of agar-agar and other substances, etc.

Subkingdom higher plants

Spore plants

Department Bryophytes

Bryophytes originated from algae and represent an evolutionary dead end. The Bryophytes department includes about 25 thousand species. Typically, the size of mosses ranges from 1 mm to 60 cm. Some mosses are a thallus, others have a stem and leaves. Bryophytes do not have roots. Some of them have single- or multicellular rhizoids, with which they attach to the ground and absorb water and minerals.
In the life cycle of mosses, the haploid gametophyte predominates over the diploid sporophyte. This distinguishes them from other higher plants. The gametophyte develops from a haploid spore. In different species of mosses, the gametophyte can be same-sex(dioecious) or bisexual(monoecious). On the gametophyte in the organs of sexual reproduction ( gametangia) motile sperm and immobile eggs are formed. Male reproductive organs are called antheridia, female reproductive organs are called antheridia. archegonia. Fertilization occurs in the presence of droplet-liquid moisture. A spore capsule develops from a fertilized zygote.
Thus, an adult moss plant is a sexual generation (gametophyte), and a capsule with spores is an asexual generation (sporophyte). Sexual and asexual generations are not separated, but represent one plant. Mosses are also characterized by vegetative reproduction. The largest class of bryophytes is Leaf mosses. There are green mosses (cuckoo flax) and sphagnum (white) mosses (sphagnum).
Green mosses. Representative - cuckoo flax, a perennial plant up to 20 cm high. Widely distributed in spruce forests and swamps. Gametophytes of cuckoo flax are dioecious (dioecious), have erect, unbranched stems with sharp leaves and rhizoids. Antheridia and archegonia form at the tips of male and female gametophytes. During rain or dew, biflagellate sperm penetrate the eggs and fuse with them. After fertilization, a diploid sporophyte is formed on female plants - a capsule on a long stalk. A sporangium with haploid spores is formed inside the capsule. Once in the soil, the spore grows into a green branching thread - protonema, similar to green algae. Part of the protonema goes deep into the soil, loses chlorophyll and turns into rhizoids; and from the ground part of the protonema a moss stem with leaves is formed.
Sphagnum (white) mosses. Representative - sphagnum, plays an important role in the formation and life of swamps. Sphagnum is whitish-green in color, as it contains a large number of air-bearing cells, has branched stems, seated with small leaves, and does not have rhizoids. Water is absorbed by the entire surface. Sphagnum mosses grow on the upper part of the shoots, and the lower part dies. As a result, peat deposits are formed. The process of peat formation occurs due to stagnant waterlogging, lack of oxygen and the creation of an acidic environment by mosses.
Meaning. Mosses play an important role in nature: as moisture accumulators, they participate in regulating the water balance of forests and neighboring areas.
Peat is used by humans as fuel, as a thermal insulator, in agriculture as a fertilizer, in the chemical industry for the production of paraffin, phenol, ammonia, acetic acid, methanol, dyes and other substances, in medicine for mud therapy, and can also be used as a bactericidal dressing material, as it has an antiseptic effect.

Department Lycopods

Moss-moss, horsetail-like and pteridophytes are ancient groups of higher plants. They came from psilophytes (rhiniophytes), which, in turn, originated from green algae and were the first to populate the land. Their heyday occurred during the Carboniferous period, after which many species became extinct.
Moss-moss- These are herbaceous, perennial plants found in damp coniferous and mixed forests. Currently there are about 1 thousand species. They have a creeping stem with many branches covered with small dark green leaves, anchored in the soil with the help of adventitious roots. The apical shoots end in spore-bearing spikelets.
The spores form small growths (2–3 mm), which develop underground; after 15–20 years, archegonia and antheridia form on them. Multiflagellate sperm are formed in them, which in the presence of water fertilize the eggs, and a new plant develops from the diploid zygote. In addition, lycophytes can reproduce vegetatively (by parts of the stem).
Meaning. Mosses grow very slowly and must be protected. Not eaten by animals. Used in medicine (some contain a poison similar in action to curare, others are used as a powder, and others are used to treat alcoholism).

Department Horsetails

Horsetails- These are perennial herbaceous plants that live in moist acidic soil in damp forests, swamps, wet fields and meadows. Currently there are only about 20 species. They have a well-developed rhizome with tubers. Shoots consist of segments (internodes). Silica accumulates in the cell walls, which plays a mechanical and protective role. At the tops of the shoots there are spore-bearing spikelets.
In spring, pinkish spore-bearing shoots with spore-bearing spikelets grow on the rhizomes, on which haploid spores are formed. From them grow male and female (larger) shoots. Fertilization takes place in a liquid medium. A sporophyte develops from a diploid zygote.
Meaning. Horsetails are inedible for animals and are weeds of pastures and fields. Horsetail is used medicinally as a diuretic.

Division Ferns

Ferns- perennial, often herbaceous plants of temperate zone forests (bracken), reservoirs (salvinia) or tree-like, liana, epiphytic inhabitants of the humid tropics. Currently there are about 10 thousand species.
The sporophyte of ferns is divided into root, stem and leaf. Adventitious roots extending from the rhizome. The stems are poorly developed, and the foliage prevails over the stem in weight and size. Sporangia develop on the lower part of the leaf.
From a spore develops outgrowth- a small multicellular plate of green color and with rhizoids (an independent plant). Antheridia (male genital organs) and archegonia (female genital organs) are formed on the prothallus. The shoots of some species are bisexual, while others are unisexual. Antheridia produce sperm, and archegonia produce eggs. For their fusion, the presence of water is necessary. After fertilization, a fern plant develops from the zygote. Thus, the prothallus is the sexual generation (gametophyte), and the adult fern plant is the asexual generation (sporophyte). Sexual and asexual generations are separated. Ferns are also characterized by vegetative propagation (for example, by separating rhizomes).
Meaning. The role of ancient ferns, as well as horsetails and mosses, was in the formation of coal deposits and saturation of the atmosphere with oxygen. Some types of modern ferns are eaten, used in medicine (anthelmintics) or as ornamental plants.

Seed plants

The spore plants discussed above have two common properties:

1. To carry out the sexual process, they need droplet-liquid moisture, which limits their spread.
2. The resulting spores are small, contain few nutrients and have poor viability. The same applies to the development of spore plant embryos from the zygote.

More progressive from an evolutionary point of view are seed plants. They do not require water for fertilization, and the seed (the unit of dispersal of seed plants) contains a supply of nutrients. The seed is a small sporophyte with a root, bud and embryonic leaves - cotyledons. It contains the supply of nutrients necessary for the initial stage of development.
Mature seed plants - sporophytes. They form two types of spores: male (microspores) and female (megaspores). Microspores are produced in male cones (in gymnosperms) or in anthers (in flowering plants). Inside the pollen grain, the microspore divides and produces male gametophyte, in which they are formed male gametes. Male gametes formed inside microspores, as a rule, lack flagella, are not able to actively move and are called sperm. Megaspores are formed in the ovules of female cones or ovaries. The only mature female spore remains in the ovule, here it develops female gametophyte(embryo sac), where it is formed egg. Thus, gametophytes in seed plants are extremely reduced, and their entire development cycle takes place on the sporophyte.
Seed plants include gymnosperms(reproduce by seeds, but do not produce fruits) and angiosperms(seeds are enclosed in fruits).

Division Gymnosperms

In the Gymnosperms department, there are 6 classes: Seed ferns, Cycads, Bennettitaceae, Gnetaceae, Ginkgoaceae, Conifers. Of these, seed ferns and bennettites have become completely extinct. The most widespread gymnosperms were distributed at the end of the Paleozoic and Mesozoic eras. There are about 720 species of living gymnosperms. Gymnosperms are represented exclusively by arboreal forms: trees, shrubs, vines.
Both in nature and in human life, conifers occupy second place after flowering plants. There are about 560 species. These include pine, spruce, larch, fir, cedar, cypress, juniper, etc.
Structure. Conifers have a taproot system. Often contain mycorrhizae. Wood is made up of 90–95% strong, conductive tissue. Among conifers there are deciduous and evergreen species. In deciduous species (larch) leaves are flat and soft. In evergreens(most conifers) leaves are needle-shaped and rigid. The stomata are deeply embedded in the leaf tissue, which reduces water evaporation. The needles contain vitamin C and secrete phytoncides.
Reproduction. Let's consider the reproduction of conifers using the example of pine. Pine is a monoecious (bisexual plant). At the tops of young shoots reddish female cones. The cone consists of an axis on which the scales are located, and on each scale there are two ovule. At the base of young pine shoots there are groups of greenish-yellow male bumps. They form pollen. Each speck of dust is equipped with two air sacs. Ripe pollen, with the help of the wind, falls on the ovules of female cones, after which their scales tightly close and are glued together with resin. The speck of dust remains inside the ovule until the spring of next year. It takes 12–14 months from pollination to fertilization. Pollen germinates, a pollen tube develops from the vegetative cell, and two sperm cells develop from the generative cell. One fuses with the egg, and the second dies. An embryo with a supply of nutrients develops from the zygote, and the seed coat is formed from the integument of the ovule. After the seeds ripen, the scales of the cones separate and the seeds spill out.
Meaning. Conifers are most widely distributed in the temperate zone of the northern hemisphere, where they form the taiga. Man uses conifers as a building material, raw material for the pulp and paper industry, fuel, as a source of resins, essential oils, medicines, etc. Larch wood is resistant to rotting. Sequoia and mammoth tree - representatives of the cypress family - have valuable wood (“mahogany”). Some sequoias reach a height of more than 100 m and are 3–4 thousand years old. Representatives of cycads are used by humans for food (“breadfruit”).

Department Angiosperms (Flowering)

Angiosperms- evolutionarily the youngest and most numerous group of plants. The department includes about 250 thousand species. Angiosperms grow in all climatic zones, make up the bulk of plant matter in the biosphere and are the most important producers (producers) of organic matter on land.
The dominant role of flowering plants is due to a number of progressive features:

1. Appearance flower- an organ that combines the functions of asexual reproduction (spore formation) and sexual reproduction (seed formation).
2. Formation within a flower ovaries, which contains the ovules (ovules) and protects them from adverse environmental influences.
3. Formation from the ovary fetus: The seeds are located inside the fruit and are therefore protected (covered) by the pericarp. In addition, the fruit allows the use of various agents for seed dispersal (insects, birds, bats, as well as air and water currents).
4. Double fertilization, as a result of which a diploid embryo and triploid (and not haploid, as in gymnosperms) endosperm are formed.
5. Maximum gametophyte reduction. The male gametophyte - a pollen grain - consists of two cells: vegetative and generative, which divides to form two sperm. The female gametophyte consists of eight embryo sac cells, one of which becomes the egg.
6. Reproduction and seeds, And vegetative organs.
7. Complication and high degree of differentiation of organs and tissues. In particular, the most perfect conducting system: xylem is represented by vessels, not tracheids; in phloem, sieve tubes have a segmented structure, satellite cells appear.
8. Rapid growth and development processes in annual forms.
9. Big diversity of life forms: trees, shrubs, shrubs, subshrubs, perennial herbs, annual herbs, etc.
10. Can form complex multi-tiered communities due to the wide variety of life forms.

Meaning It is difficult to overestimate the importance of angiosperms in human life. Almost all cultivated plants belong to this division. Angiosperm wood is used in industry, construction, paper making, furniture, etc. Many flowering plants are used in medicine.
Taxonomy. The department Angiosperms (Flowers) is divided into two classes: Dicotyledons and Monocots. Monocots evolved from dicots and are less numerous. Dicotyledons are distinguished from monocotyledons by a number of characteristics. There are many exceptions for each of the characteristics. The only absolute sign is the structure of the embryo.

Comparative characteristics of the main classes of angiosperms

Sign	Dicotyledons	Monocots
The structure of the embryo	The embryo usually has two cotyledons; the embryo is symmetrical - the bud occupies the apical position, and the cotyledons are located on the sides of the embryo; cotyledons usually germinate aboveground	Embryo with one cotyledon; the embryo is asymmetrical - the cotyledon occupies the apical position, and the bud is located on the side; cotyledon usually germinates underground
Leaf structure	The venation is usually reticulate, less often pinnate or arcuate; leaves are usually petiolate, falling	The venation is usually parallel or arcuate; leaves are usually sessile, non-deciduous
Root system	Usually rod-shaped	Usually fibrous
Features of growth	There is a cambium: secondary growth is characteristic	Cambium is usually absent: secondary growth is not typical
Life forms	Woody, semi-woody and herbaceous forms	Herbs. Sometimes secondary woody forms (palms)
Flowers	Usually five-membered, less often four-membered	Usually three-membered, rarely four-membered, but never five-membered

Flowering classes are divided into families mainly based on the structure of the flower and fruit. In this case, the flower formula is used.
Class Dicotyledons includes the families Cruciferae, Chenoceae, Pumpkin, Legumes, Rosaceae, Solanaceae, Asteraceae.
Class Monocots includes the families Poaceae and Liliaceae.

Family name	Number of species	Life forms	Flower structure	Fetus	Other Features	Cultivated plants	Wild plants
Class Dicotyledons
Cruciferous (brassicas)	3 thousand species	Mainly herbs, less often shrubs and shrubs	P 4 L 4 T 4 P 1 . Inflorescence: raceme	Pod or pod	The leaves are alternate, many forming a basal rosette. Good honey plants. Contains oils (mustard, rapeseed)	Cabbage, radish, turnip, mustard, rapeseed	Crescent, shepherd's purse, noctule (night violet)
Legumes	17 thousand species	Herbs, subshrubs, shrubs, trees	P (5) L 1+2+(2) T (9)+1 P 1 . Petals: sail, 2 oars, boat (from two fused petals). Inflorescences: raceme, head	Bean	The leaves are compound. Nodule bacteria on the roots. Seeds are rich in protein	Beans, peas, beans, soybeans, lentils, peanuts	Alfalfa, clover, china, sweet clover, licorice
Rosaceae	3 thousand species	Herbs, shrubs, trees	Ch 5 L 5 T oo P 1 or Ch 5 L 5 T oo P oo. Inflorescences: raceme, umbrella, etc.	Drupe, apple, nut	A wide variety of fruits that are rich in vitamins, sugars, organic acids	Cherry, plum, apricot, apple, pear, strawberry, raspberry	Rosehip, bird cherry, cinquefoil
Solanaceae	2 thousand species	Mainly herbs, less often subshrubs and shrubs	H (5) L (5) T 5 P 1 . Inflorescences: curl, double curl	Berry, box	The leaves are simple: whole or dissected, without stipules. Some plants contain toxic substances	Potatoes, tomatoes, eggplants	Henbane, datura, belladonna
Compositae	20 thousand species	Most are grasses, in the tropics there are shrubs and trees	L (5) T (5) P 1 . The calyx is represented by a tuft of hairs. Inflorescence: basket	Achene	Leaves are simple without stipules	Sunflower, lettuce, Jerusalem artichoke, chicory, asters, dahlias	Dandelion, chamomile, coltsfoot, tansy, yarrow
Class Monocots
Liliaceae	2 thousand species	Herbs	O (3)+3 T 3+3 P 1 . Inflorescence: raceme	Box, berry	The leaves are lance-shaped with parallel veins, collected in a basal rosette. The stem is modified and represented by a bulb	Tulip, lilies. Onions, garlic and some other species are currently classified in a special family, Alliums.	Lily of the valley, aloe
Cereals	12 thousand species	Herbs	O (2)+2 T 3 P 1 .	Caryopsis	The leaves are entire, with parallel veins, and mostly vaginal. The stem is hollow inside (straw). Stem growth is intercalary - as a result of cell division at the base of each internode	Wheat, rice, barley, corn, oats, millet, sorghum, sugar cane	Feather grass, wheatgrass, bluegrass