Algae are the original inhabitants of the seas, widespread in fresh waters. Higher plants are terrestrial plants that have mastered the land, as well as fresh and brackish water bodies. Only a very few representatives of higher plants have adapted to life in sea water.
The emergence of plants on land was accompanied by the development of a system of adaptations to new living conditions, which significantly changed their appearance.
The possible appearance of the first terrestrial plants is judged by several finds that were of great importance for the study of the structural evolution of higher plants.
In 1859, J. Dawson discovered the fossilized remains of a plant in the Devonian deposits of Canada, which was called the "primary goloros" - Psilophyton princeps. The plant was a system of forked axes covered with small spines (Fig. 11b). Sporangia were located at the ends of arcuately curved drooping branches. The unusual appearance of the goloros did not allow it to be attributed to any of the plant taxa known at that time, and for a long time it remained a mystery of nature.
In 1912, rhynia ( Rhynia), which differs from the goloros by the absence of any outgrowths on the axes and vertically oriented terminal sporangia (Fig. 11B). We have already mentioned the most ancient paleontological find - kuksonia.
These and other ancient plants similar to them were previously combined into one taxon called psilophytes ( psilophyta). However, the discovered plants most likely were representatives of groups that had already diverged far enough in the process of rapid evolution. It's not very significant. It is important that the study of the remains of all the most ancient terrestrial plants found was of great importance for clarifying the initial model of the structure of higher plants and developing ideas about their morphological evolution.
It is no coincidence that at the end of the 19th and beginning of the 20th centuries attempts were made to create hypothetical models of the ancestors of higher plants. The greatest attention of researchers has attracted telome theory structure of the most ancient plants, in the development of which the main role belongs to V. Zimmerman (30-40s of the XX century).
According to the telome theory, the ancestors of higher plants had an axial organization. The presence of sporangia in goloros, rhynia, cooksonia and other plants that existed in the Silurian and Devonian proves that they were sporophytes, the main purpose of which is the formation of spores. To disperse the spores, the sporangia must be raised above the substrate. Consequently, the development of the sporophyte must have been accompanied by an increase in its size. This required the necessary amount of food absorbed by the surface of the plant from the soil, which was clearly not enough, since its formation is associated with the decomposition of plant residues. The increase in the surface, which occurred with the slow growth of the sporophyte, was achieved by its division, the simplest method of which was the forked branching of the axial organs. Their terminal branches were called telomes (from the Greek telos - end), and the parts connecting them - mesomas (from the Greek mesos - middle). Telomes were of two types: fertile, with sporangia at the top, and sterile that perform the function of photosynthesis.
The underground part of the plant also forked branched. Numerous rhizoids developed on the surface of terminal branches. These branches were later named rhizomoids(Takhtadzhyan, 1954). Thus, according to the telome theory, the main organs of the most ancient terrestrial plants were telomes, rhizomoids, and mesomes connecting them (Fig. 12).
Rice. 12. Structure diagram
hypothetical
sporophyte of a higher plant.
Designations: mz - me-
zom, r - rhizoids,
rzm - rhizomoid, cn -
sporangium, s.t - sterile
body, f.t -
fertile body
The study of paleobotanical material, mainly ferns, allowed G. Potonier (1912) to conclude that forked or dichotomous branching was the source for other types of branching (Fig. 13).
Rice. thirteen. Scheme of branching evolution of higher sporophytes
plants: A - equal dichotomy (isotomy); B - unequal
dichotomy (anisotomy); B - dichopodium; G - monopodium;
D - sympodium
At dichotomous branching splits (bifurcates) the growth zone located at the top of each axis. Therefore, dichotomous branching is also called apical. The starting point for the evolution of this branching was an equal dichotomy - isotomy(Fig. 13 A), in which both branches grew at the same rate, and then their tops bifurcated again. If one of the branches was ahead of the other in development, an unequal dichotomy arose - anisotomy(Fig. 13 B). A sharp lag in the development of one of the branches led to dichopodial branching (Fig. 13B), with the formation of a zigzag curved main axis of the plant.
From dichotomous branching, 2 types of lateral branches have developed.
The straightening of the main axis (first-order axis) of the dichopodium and its acquisition of the ability for unlimited apical growth led to monopodial branching(Fig. 13 D). In this case, lateral branches, or second-order axes, were laid directly under the top of the main axis and were significantly inferior to it in development. On the axes of the second order, the beginnings of the axes of the third order were laid in the same way, and so on.
In the most ancient plants, the second type of lateral branching was also revealed - sympodial(Fig. 13 E). In this case, the growth of the main axis ceased with time, and the lateral branch of the second order of branching, located near its top, straightened up, displaced the end of the main axis to the side, and itself began to grow in the direction in which the main axis used to grow. Then its growth also stopped, and its apex moved aside was replaced by a new lateral branch of the third order of branching, etc. As a result, a straight or cranked axis appeared, which was a system of axes of different branching orders growing one on top of the other.
Branching was not the only way to increase the surface of the sporophyte.
The telomes were cylindrical and had an oblique-vertical orientation. Only a small part of their surface was turned to the sun's rays. An increase in the size of the light-receiving surface was achieved by the formation of flattened organs - leaves, oriented more or less horizontally. Axial organs bearing leaves have turned into stems. This is how leafy plants arose. In appearance, they differ greatly. One of them, called microphilic(from the Greek mikros - small and phyllon - leaf), have numerous small leaves, others called macrophilic(from the Greek makros - large) are characterized by large leaves, often of a very complex structure.
According to the telome theory, the formation of leaves in the macrophyllic line of plant evolution was determined by several interrelated processes (Fig. 14 B).
1. aggregation, or crowding, of telomes, which occurs as a result of shortening and sometimes reduction of mesomes;
2. "reversal", due to the uneven development of sterile bodies, while one of them, with unlimited growth in length, became a stem, and the other body of the same dichotomy, greatly lagging behind in growth, shifted to the side and turned into a lateral organ;
3. fusion of telomes;
4. their flattening;
5. reduction of some telomes or their parts.
Rice. fourteen. Diagram illustrating
origin of enations (row A)
and typical leaves (row B)
All these processes were carried out simultaneously and were accompanied by a change in the planes of branching, which from a comprehensive one became two-sided, and then one-sided. Clustering of telomes, their branching in one plane, coalescence by edges and reduction up to the disappearance of sporangia located on some telomes eventually led to the formation of a lamellar organ - a leaf, which assumed the functions of photosynthesis. A classic example of leaves of this origin are the leaves of ferns, which have a long apical growth.
The appearance of leaves greatly increased the surface of plants, which activated the processes of assimilation, gas exchange and transpiration (evaporation). Such plants could develop only at high humidity of the environment. In the process of evolution, the size of the leaves decreased due to the weakening of their growth, they acquired adaptations that limited transpiration. All this expanded the adaptive capabilities of plants. Of modern plants, macrophyllia is characteristic not only of ferns, but also of seed plants.
- Metabolism is the main feature of living things. The constant exchange of each living organism with the environment substances: the absorption of some substances and the release of others. Absorption by plants and some bacteria from the environment of inorganic substances 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 by humans, organic substances and the energy of the Sun stored in them.
- essence of the exchange.
The main thing in the metabolism and energy conversion is the processes occurring in the cell: the entry of substances into the cell from the environment, with the help of energy their transformation and the creation (synthesis) of certain cell substances from them, then the oxidation of organic substances to inorganic substances with the release of energy. Plastic metabolism is the process of assimilation by the body of substances obtained from the environment and the accumulation of energy. Energy metabolism - oxidation in most organisms of organic substances and their splitting to inorganic - carbon dioxide and water with the release of energy. The value of energy metabolism is the provision of energy for all vital processes of the body. The relationship of plastic and energy exchanges. Release of end products of metabolism (water, carbon dioxide and other compounds) into the environment.
The value 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.
- Causes of plant evolution: the 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 their life, the transmission of some of them to offspring by inheritance. Preservation by natural selection of changes useful under certain conditions, their transmission to offspring in the process of reproduction. The role of natural selection, which has been going on continuously for 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 of multicellular algae as a result of variability and heredity, the preservation of this beneficial feature by natural selection. The origin from ancient algae of more complex plants - psilophytes, and from them - mosses and ferns. The appearance of organs in ferns - a stem, leaves and roots, a more developed conducting system. Origin from ancient ferns due to heredity and variability, the action of natural selection of ancient gymnosperms, which produced 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 peel. A significantly higher probability of a new plant from a seed than from a spore that has a small supply of nutrients. Origin from ancient gymnosperms more complex plants - angiosperms, which had a flower and a fruit. The role of the fruit is to protect the seed from adverse 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, the action of natural selection.
- The magnification of a school microscope is determined by multiplying the numbers on the objective and eyepiece indicating their magnification. To work with a microscope, you need to put it with a tripod towards you, point the light at the opening of the object table with a mirror, put a micropreparation on the table, fix it with clamps, lower the tube down to the limit without damaging the micropreparation, and then, looking into the eyepiece, slowly raise it with screws. tube until a clear image is obtained.
- The structure of the heart. Providing blood circulation by the activity of the heart and blood vessels. The heart is the central organ of the circulatory system. The mammalian and human heart has four chambers: two atria and two ventricles. Separation of the heart by a solid partition into the right and left halves, the presence of openings between the atria and ventricles, which are closed and opened by flap valves. Semilunar valves on the border between the left ventricle and the aorta, the right ventricle and the pulmonary artery. The activity of the valves, which ensures the movement of blood in one direction, for example, from the atria to the ventricles, from them to the arteries. The striated muscle tissue that forms the walls of the heart. Properties of the striated muscle tissue of the heart that provide work: excitability and conductivity, as well as the ability to spontaneously contract rhythmically under the influence of impulses arising in the heart muscle. Large thickness of the walls of the ventricles compared with the walls of the atria.
- The function of the heart is to pump blood. The rhythm of his work throughout the life of man and animals. In case of cardiac arrest, the delivery of oxygen and nutrients by the blood to the tissues, as well as the removal of decay products from the tissues, is interrupted. The dependence of the working capacity of the heart on the level of metabolic intensity in it, the alternation of work and rest of each part of the heart, the intensity of the supply of blood to the heart muscle.
- The structure and function of blood vessels. Injection of blood by the heart into the vessels: arteries, veins, capillaries. The presence in the walls of the arteries, through which blood flows from the heart, many elastic fibers. Veins are less elastic (there are few muscle fibers in their walls), but more extensible than arteries. Capillaries are thin blood vessels, the walls of which consist of a single layer of cells. The presence of numerous small holes in the cell membranes of capillaries, their significance. Exchange of liquids, nutrients, gases between blood, tissues and intercellular substance in capillaries.
- Reasons for evolution: heredity, variability, struggle for existence, natural selection. The discovery of the English scientist Charles Darwin.
- The first chordates. Cartilaginous and bony fishes. The ancestors of chordates are bilaterally symmetrical animals, similar to annelids. Active way of life of the first chordates.
- The origin of two groups of animals from them:
sedentary (including the ancestors of modern lancelets) and free-swimming, with a well-developed spine, brain and sensory organs. Origin from ancient free-swimming chordate ancestors of cartilaginous and bony fishes.
A higher level of organization of bony fish compared to cartilaginous ones: the presence of a swim bladder, a lighter and stronger skeleton, gill covers, a more perfect way of breathing. This allowed bony fish to spread widely in fresh water, seas and oceans.
- Origin of ancient amphibians. One of the groups of ancient bony fish - the lobe-finned ones - the ancestors of ancient amphibians. As a result of hereditary variability and the action of natural selection, the formation of dissected limbs in lobe-finned fish, adaptations for air breathing, and the development of a three-chambered heart.
- The origin of ancient reptiles from ancient amphibians. The habitat of ancient amphibians is wet places, the banks of reservoirs. Penetration into the depths of the land by their descendants - ancient reptiles, which developed adaptations for reproduction on land, instead of the mucous glandular skin of amphibians, a horny cover was formed that protects the body from drying out.
- Origin of birds and mammals. Ancient reptiles are the ancestors of the ancient higher vertebrates - birds and mammals. Signs of their higher organization: a highly developed nervous system and sensory organs; four-chambered heart and two circles of blood circulation, excluding mixing of arterial and venous blood; more intensive metabolism; highly developed respiratory system; constant body temperature, thermoregulation, etc. More complex and progressive among mammals are primates, from which man originated.
- 2-3 drops of iodine-tinted water are applied to a glass slide. A small part of the transparent skin is removed from the white fleshy scales of the onion and placed on a glass slide in tinted water. Straighten the skin with a needle and cover with a coverslip. The micropreparation is placed on the microscope stage, illuminated with a mirror, and the tube is lowered with screws. Then the tube is raised until a clear image is obtained. They look through the entire preparation, find the most successful place, choose one cell, distinguish its parts. Then the cell is sketched and the shell, cytoplasm and nucleus are signed.
- Composition and value of blood. Blood is a type of connective tissue, a bright red liquid that brings nutrients and minerals, water, oxygen, vitamins, hormones to the cells, and brings waste products to the kidneys, skin and lungs. Blood regulates body temperature, produces substances that destroy microorganisms.
- Blood plasma and its functions. Plasma - the main part of the blood, which contains blood cells - leukocytes and erythrocytes, as well as platelets - platelets. Plasma is a colorless liquid containing 90% water, 10% organic substances (proteins, vitamins, hormones) and mineral salts (sodium, potassium, calcium chlorides, etc.). The relative constancy of the chemical composition of the plasma, its significance. The detrimental effect on the body of changes in the chemical composition of the plasma.
- The structure and functions of erythrocytes. The content in the blood of up to 5 million erythrocytes - red cells, having the shape of a biconcave disc, which results in an increase in their surface, and hence an increase in the amount of oxygen entering them. The absence of a nucleus in mature erythrocytes contributes to the transfer of large amounts of oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs. The content of hemoglobin protein in erythrocytes, which determines their color. The addition of oxygen in the capillaries of the lungs to hemoglobin and its transformation into oxyhemoglobin, and in cells where there is little oxygen, the destruction of oxyhemoglobin and its transformation into hemoglobin with the release of oxygen.
- Leukocytes and platelets. Leukocytes are colorless cells with a nucleus, having an unstable shape, capable of moving, penetrating through small holes in the walls of capillaries into a liquid intercellular substance, capturing and digesting bacteria and foreign bodies that have entered the body. The ability of certain types of leukocytes to produce antibodies that cause the death of microorganisms. Platelets are small non-nuclear bodies that contribute to blood clotting.
- Blood transfusion. With a large loss of blood by a sick person, a transfusion to him from a healthy donor of blood that is compatible with the blood of the patient and does not cause the destruction of red blood cells in it. Four blood groups, differing in the content of proteins in plasma and erythrocytes. Inheritance of blood groups by a person, their invariance throughout life.
- Reproduction and its importance. Reproduction is the reproduction of similar new organisms, which ensures the existence of species for many millennia, contributes to an increase in the number of individuals of a species, the continuity of life. Asexual, sexual and vegetative reproduction of organisms.
- asexual reproduction - the most ancient way. In this method of reproduction, one organism participates, while two individuals most often participate in sexual reproduction. In plants, fungi reproduce asexually with the help of spores - one specialized cell. Reproduction by spores of algae, mosses, horsetails, club mosses, ferns. Eruption of spores from plants, their germination and the development of new daughter organisms from them when they fall into favorable conditions. The death of a huge number of spores that fall into adverse conditions. The probability of emergence of new organisms from spores is low, since they contain few nutrients and the seedling absorbs them mainly from the environment.
- Vegetative propagation - the ability of a plant to restore a complete organism from its vegetative organs: an above-ground or underground shoot, part of a root, leaf, tuber, bulb. Participation in vegetative reproduction of one organism or part of it. The similarity of the daughter plant with the mother, as it continues the development of the mother's organism. Greater efficiency and distribution of vegetative reproduction in nature, since the daughter organism is formed faster from a part of the mother than from a spore. Examples of vegetative propagation: with the help of rhizomes - lily of the valley, mint, wheatgrass, etc.; rooting of the lower branches touching the soil (layering) - currants, wild grapes, etc .; mustache - strawberries, etc.; bulbs - tulips, daffodils, crocuses, etc. The use of vegetative propagation in the cultivation of cultivated plants: potatoes are propagated with tubers, onions and garlic are propagated with bulbs, currants and gooseberries are layered, root suckers are cherries, plums, cuttings are fruit trees.
- Sexual reproduction. The essence of sexual reproduction is in the formation of germ cells (gametes), fertilization - the fusion of the male reproductive cell (sperm) and female (ovum) and the development of a new daughter organism from a fertilized egg. Due to fertilization, the daughter organism receives a more diverse set of chromosomes, and hence more diverse hereditary traits, as a result of which it may be more adapted to the environment. The presence of sexual reproduction in algae, mosses, ferns, gymnosperms and angiosperms. The complication of the sexual process in the course of plant evolution, it is most complex in seed plants.
- seed propagation occurs with the help of seeds, it is characteristic of gymnosperms and angiosperms (vegetative propagation is also widespread in angiosperms). The sequence of stages of seed reproduction: pollination - the transfer of pollen on the stigma of the pistil, its germination, the appearance by dividing two sperm, their advancement into the ovule, then the fusion of one sperm with the egg, and the other with the secondary nucleus (in angiosperms). The formation of a seed from the ovule - an embryo with a supply of nutrients, and from the walls of the ovary - a fetus. The seed is the germ of a new plant, it germinates under favorable conditions, and at first the seedling feeds on the nutrients of the seed, and then its roots begin to absorb water and minerals from the soil, and the leaves absorb carbon dioxide from the air and use the energy of sunlight for the formation of organic substances from inorganic. Independent life of a new plant.
- Prepare two microscopes for work, put micropreparations of the indicated tissues on the object tables, illuminate the field of view of the microscopes, and achieve a clear image by moving the tube with screws. Consider micropreparations, compare them and indicate the following differences: epithelial tissue cells are tightly adjacent to each other, and connective tissue are located loosely. There is little intercellular substance in the epithelial tissue, and a lot in the connective tissue.
- The role of the skin, mucous membranes, fluids they secrete (saliva, tears, gastric juice, etc.) in protecting the body from microbes. They serve as a mechanical barrier, a protective barrier blocking the way for microbes to enter the body; produce substances with antimicrobial properties.
- The role of phagocytes in protecting the body from microbes. The penetration of phagocytes - a special group of leukocytes - through the walls of the capillaries to the places of accumulation of microbes, poisons, foreign proteins that have entered the body, enveloping and digesting them.
- Immunity. The production of antibodies by leukocytes, which are carried by the blood throughout the body, combine with bacteria and make them defenseless against phagocytes. The contact of certain types of leukocytes with pathogenic bacteria, viruses, the release of substances by leukocytes that cause their death. The presence of these protective substances in the blood provides immunity - the ability of the body to protect itself from pathogenic microbes. The action of different antibodies on microbes.
- Prevention of infectious diseases. The introduction into the human body (usually in childhood) of weakened or killed pathogens of the most common infectious diseases - measles, whooping cough, diphtheria, poliomyelitis and others - to prevent the disease. A person's immunity to these diseases or the course of the disease in a mild form due to the production of antibodies in the body. When a person is infected with an infectious disease, the introduction of blood serum obtained from recovered people or animals. Serum levels of antibodies against a particular disease.
- Prevention of HIV infection and AIDS. AIDS is an infectious disease based on a lack of immunity. HIV is a human immunodeficiency virus that causes a loss of immunity, which makes a person defenseless against the infectious disease AIDS. Infection through sexual contact, through blood transfusion, due to poor sterilization of syringes, during childbirth (infection of a child from a mother who is a carrier of AIDS pathogens). The importance of preventing AIDS virus infection due to the lack of effective treatment: strict control of donated blood and blood products, the use of disposable syringes, the exclusion of promiscuity, the use of condoms, early diagnosis of the disease.
- characteristics of the plant kingdom. Variety of plants: algae, mosses, ferns, gymnosperms, angiosperms (flowering). General features of plants: they grow all their lives, they do not actively move from one place to another. The presence in the cell of a strong shell of fiber, which gives it a 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 a green pigment - chlorophyll. The mode of nutrition is autotrophic: plants independently create organic substances from inorganic substances using solar energy (photosynthesis).
- The role of plants in the biosphere. The ability to use solar energy to create organic substances in the process of photosynthesis and release oxygen, which is necessary for the respiration of all living organisms. Plants are producers of organic matter, providing food and energy for themselves, as well as animals, fungi, most bacteria and humans. The value of plants in maintaining a certain level of carbon dioxide and oxygen in the atmosphere.
- Prepare two microscopes for work, put micropreparations of two tissues on the object tables. Illuminate the field of view of the microscope, by moving the tube to achieve a clearer image. Consider micropreparations using knowledge of the signs of epithelial tissue. Choose the one you need from the tissue samples, noting that the cells of the epithelial tissue are tightly adjacent to each other, have practically no intercellular substance, which contributes to their protective function.
- The movement of blood in the human body in two circles of blood circulation - large and small. The flow of blood in a large circle to the cells of the body, and in a small circle - to the lungs.
- Great circle of blood circulation. Ejection of oxygenated arterial blood from the left ventricle of the heart into the aorta, which branches into arteries. The flow of blood through them into the capillaries - the smallest vessels with many pores. The flow of oxygen from the capillaries to the cells of the body, and carbon dioxide from the cells to the capillaries. Saturation of blood in the capillaries with carbon dioxide, turning it into venous. The movement of venous blood through the veins into the right atrium.
- Small circle of blood circulation. The flow of venous blood from the right atrium into the right ventricle, the expulsion of venous blood from it into the pulmonary artery, which branches into many capillaries that braid the pulmonary vesicles. The diffusion of oxygen from the pulmonary vesicles into the capillaries is the transformation of venous blood into arterial blood, and carbon dioxide from the capillaries into pulmonary vesicles. Removal of carbon dioxide from the body during exhalation. Return through the veins of a small circle of arterial blood, saturated with oxygen, to the left atrium, and from it to the left ventricle.
- living conditions of land animals. Sharp fluctuations in temperature (during the day and year) and illumination, low humidity, high oxygen content, low air density. The evolution of animals in the direction of the formation of adaptations to life in terrestrial conditions - movement on land, breathing oxygen from the air, feeding on land plants and animals.
- Exit of vertebrates to land. Adaptation of ancient lobe-finned fish, which lived 400-500 million years ago, to living in a dry and hot climate, in shallow, drying up reservoirs. Survival in these conditions of such fish that could move along the bottom of semi-dry water bodies, as well as overland to other water bodies. The role of trait variability, heredity and natural selection in the transformation of paired fins of lobe-finned fishes into dissected limbs, in the formation of lungs. Significant reduction in energy costs for movement due to changes in the structure of the skeleton and muscles of the limbs.
- Ancient amphibians - the first land animals. Loss of scaly cover in connection with the transition to a terrestrial lifestyle, the acquisition of the ability to breathe air oxygen with the help of the lungs and through bare, moist skin, in which a dense network of capillaries is located. The heart is three-chambered (instead of two-chambered in fish), the formation of a small circle of blood circulation. The ability to make some head movements due to the appearance of the cervical spine. The complication in the process of evolution of the structure of the nervous system and sensory organs, an increase in the relative size of the forebrain, the appearance of eyelids and lacrimal glands that protect the eyes from drying out and clogging, the appearance of the middle ear in the hearing organ, which amplifies sound vibrations. At the same time, the preservation of primitive organization traits in amphibians: their reproduction and development in water, poor development of the lungs, skin that does not protect the body from drying out, mixed blood flow to the organs during blood circulation, and unstable body temperature.
- Prepare two microscopes for work. On the object table of one microscope put a micropreparation with one tissue, and another microscope - another micropreparation. Illuminate the field of view of the microscope, move the tube to obtain a clear image. Consider the preparations, using knowledge of the signs of the integumentary tissue, choose the right one from them, explaining that the cells of the integumentary tissue fit tightly to each other, have thickened outer walls, which contributes to the protective function. Stomata located in the integumentary tissue (two specialized cells with a stomatal gap between them) are involved in gas exchange, photosynthesis and transpiration of plants.
Ticket number 10
- Breathing of plants, animals and humans, its significance. The structure of the human respiratory organs, their functions.
- Mushrooms. Features of their structure and life, the role in nature and in human life.
- Examine a ready-made micropreparation of green euglena under a microscope, explain why botanists classify it as a plant, and zoologists as an animal.
Planet Earth was formed over 4.5 billion years ago. The first single-celled life forms appeared, possibly about 3 billion years ago. First it was bacteria. They are classified as prokaryotes because they do not have a cell nucleus. Eukaryotic (with nuclei in the 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 entering a heterotrophic eukaryotic cell of a photosynthetic bacterium that was not digested. Further, the process of evolution led to the emergence of a single-celled eukaryotic photosynthetic organism with chloroplasts (their precursors). This is how unicellular algae appeared.
The next stage in the evolution of plants was the emergence of multicellular algae. They reached a great diversity and lived exclusively in the water.
The surface of the earth did not remain unchanged. Where the earth's crust was rising, land gradually arose. Living organisms had to adapt to new conditions. Some ancient algae were gradually able to adapt to the terrestrial way of life. In the process of evolution, their structure became more complicated, tissues appeared, primarily integumentary and conductive.
The psilophytes, which appeared about 400 million years ago, are considered the first land plants. They have not survived to this day.
Further evolution of plants, associated with the complication of their structure, was already on land.
During the time of the psilophytes, the climate was warm and humid. Psilophytes grew near water bodies. They had rhizoids (like roots), with which they were fixed 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 through the plant was ensured by the emerging conductive tissue.
Later, ferns and mosses originated from psilophytes. These plants have a more complex structure, they have stems and leaves, they are better adapted to living on land. However, just like the 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.
In the Carboniferous period (about 300 million years ago), when the climate was humid, ferns reached their dawn, many of their woody forms grew on the planet. Later, dying off, it was they who formed deposits of coal.
When the climate on Earth began to become colder and drier, ferns began to die out en masse. But some of their species before that gave rise to the so-called seed ferns, which, in fact, were already gymnosperms. In the subsequent evolution of plants, seed ferns died out, giving rise to other gymnosperms before this. Later, more advanced gymnosperms appeared - conifers.
The reproduction of gymnosperms no longer depended on the presence of liquid water. Pollination took place with the help of wind. Instead of spermatozoa (mobile forms), they formed sperm (immobile forms), which were delivered to the egg by special formations of pollen grains. In addition, gymnosperms did not form spores, but seeds containing a supply of nutrients.
The further evolution of plants was marked by the appearance of angiosperms (flowering). 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. It can be said that they began to use the possibilities of the environment more. So their pollination began to occur not only with the help of wind, but also through insects. This increased the efficiency of pollination. Seeds of angiosperms are found in fruits, which provide more efficient distribution. 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.
The complication of plants in the process of evolution proceeded in the following directions:cell differentiation, the formation of tissues that differ in structure and functions: educational, integumentary, mechanical, suction, conductive, assimilation (carrying out photosynthesis);
the emergence of specialized organs: a shoot, including a stem, leaves, generative organs, and a root;
a decrease in the role of the gametophyte (haploid generation) in the life cycle and an increase in the role of the sporophyte (diploid generation);
the transition to reproduction by seeds, which did not require the presence of water for fertilization;
special adaptations in angiosperms to attract pollinating insects.
The angiosperm division includes the dicotyledonous and monocotyledonous classes. The following systematic categories are studied in the school course: family, genus, species. May lily of the valley classification:
Department of angiosperms, or flowering
Monocot class
lily family
Genus lily of the valley
May lily of the valley view
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Complication plants in process evolution, classification angiosperms. Determine place kind lily of the valley May in system vegetable peace (the Department, Class, family, genus). -
Complication plants in process evolution, classification angiosperms. Determine place kind lily of the valley May in system vegetable peace (the Department, Class, family, genus). -
Complication plants in process evolution, classification angiosperms. Determine place kind lily of the valley May in system vegetable peace (the Department, Class, family, genus). -
Complication plants in process evolution, classification angiosperms. Determine place kind lily of the valley May in system vegetable peace (the Department, Class, family, genus). -
Complication mammals in process evolution. Determine place kind red fox in system animal peace(type, Class, squad, family, genus). The phylum Chordates includes the subtype Cranial, or Vertebrates. -
Vertebrates, their classification. Complication mammals in process evolution. Determine place kind red fox in system animal peace(type, Class, squad, family, genus). -
Vertebrates, their classification. Complication mammals in process evolution. Determine place kind red fox in system animal peace(type, Class, squad, family, genus). -
Classification plants For example angiosperms plants families(Nightshade, Rosaceae
The Department Angiosperms consists of two classes: Dicot and Monocot. For dicots, it is characteristic of n. -
At present, the dominant position on Earth is occupied by the Department Angiosperms (Tsvetkov) plants, considered the most evolutionarily advanced and defining view most modern biotopes. -
Classification plants For example angiosperms. Choose among herbarium specimens plants families(Solanaceae, Rosaceae, Legumes, etc.), by what signs do you recognize them. The Department Angiosperms consists of two classes: Dicot and Monocot.
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The structure and activity of algae.
Algae are photosynthetic autotrophic eukaryotic organisms.
There are about 30 thousand species of various algae. There are departments of Green, Red, Brown algae, etc. Algae are unicellular, multicellular and colonial.
The 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. Algae chloroplasts 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 surface of the soil, stones, tree bark).
Algae reproduction. Algae can reproduce asexually and sexually. To asexual applies vegetative reproduction(the division of the thallus into parts in multicellular organisms, the division of cells in two in unicellular organisms, the disintegration of colonies in colonial forms) and spore formation(formation of mobile or immobile spores in sporangia). sexual reproduction consists in the formation of gametes and their subsequent fusion to form a zygote, as well as simply the fusion of two unicellular 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 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 a symbiotic relationship with fungi. Distinctive features: 1) content in chloroplasts chlorophyll
a
and b
prevailing over other pigments; 2) the main storage product is starch
; 3) the cell wall is formed by cellulose. Green algae are unicellular(chlamydomonas, chlorella), multicellular(ulotrix, spirogyra) and colonial(volvox).
red algae distributed mainly in the warm waters of the 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, which allows them to perceive the sun's rays of that part of the spectrum that penetrate deeper into the water column; 2) the main storage product is purplish starch
, close in structure to glycogen; 3) there are no mobile stages in the life cycle. Red algae include porphyra, bangia, nemalion, etc.
brown algae distributed mainly in temperate or cold waters of the 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 mobile stages in the life cycle. Brown algae include kelp (seaweed), fucus, sargassum, macrocystis, etc.
The value of algae. Algae are an important component of the aquatic community. In the waters of the oceans, algae are the main producers of organic matter. In addition, they release oxygen, which is necessary for the respiration of animals and plants. Algae living on the soil surface are involved in soil formation. Algae have 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), to obtain agar-agar and other substances, etc.
Sub-kingdom higher plants
spore plants
Division Bryophytes
Bryophytes
descended from algae and represent an evolutionary dead end. The Bryophytes department includes about 25 thousand species. Usually the sizes of mosses are from 1 mm to 60 cm. Some mosses are thallus, others have a stem and leaves. Bryophytes do not have roots. Some of them have unicellular 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 types of mosses, the gametophyte can be gay(dioecious) or bisexual(single house). On the gametophyte in the organs of sexual reproduction ( gametangia) produce motile sperm and immobile eggs. Male reproductive organs are called antheridia, female - archegonia. Fertilization occurs in the presence of drip-liquid moisture. A spore box develops from a fertilized zygote.
Thus, an adult moss plant is the sexual generation (gametophyte), and the spore box is the asexual generation (sporophyte). Sexual and asexual generations are not separated, but represent one plant. Also, mosses are characterized by vegetative propagation. The largest class of bryophytes - Leafy 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, swamps. Cuckoo flax gametophytes are dioecious (dioecious), have erect, unbranched stems with sharp leaves and rhizoids. Antheridia and archegonia form at the tops of male and female gametophytes. During rain or dew, biflagellate spermatozoa penetrate to the eggs and merge with them. After fertilization, a diploid sporophyte is formed on female plants - a box on a long stalk. Inside the box, a sporangium with haploid spores is formed. Once in the soil, the spore germinates into a green branching thread - protonema similar to green algae. Part of the protonema deepens into the soil, loses chlorophyll and turns into rhizoids; and from the ground part of the protonema, a stem of moss 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 cells, has branched stems, seated with small leaves, and does not have rhizoids. Water absorption is carried out by the entire surface. Sphagnum mosses grow on the upper part of the shoots, and the lower part dies off. 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 are involved in the regulation of the water balance of forests and neighboring areas.
Peat is used by humans as a fuel, as a thermal insulator, in agriculture as a fertilizer, in the chemical industry to produce 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 Lycopsoides
Lycopsoid, horsetail and fern-like are ancient groups of higher plants. They originated from psilophytes (rhinophytes), which, in turn, descended from green algae and were the first to inhabit the land. Their heyday came in the Carboniferous period, after which many species became extinct.
Lycopsformes- 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, fixed in the soil with adventitious roots. The apical shoots end in spore-bearing spikelets.
Small growths (2–3 mm) are formed from the spores, which develop underground, after 15–20 years archegonia and antheridia form on them. Polyflagellated spermatozoa are formed in them, which fertilize eggs in the presence of water, and a new plant develops from a diploid zygote. In addition, lycopsids can reproduce vegetatively (parts of the stem).
Meaning. Club mosses grow very slowly and must be protected. Animals are not eaten. They are used in medicine (some contain a poison similar in action to curare, others are used as a powder, others are used to treat alcoholism).
Department of Horsetails
horsetail- These are perennial herbaceous plants that live on 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 are spore-bearing spikelets.
In spring, pinkish spore-bearing shoots grow on the rhizomes with spore-bearing spikelets, on which haploid spores are formed. Male and female (larger) growths grow from them. Fertilization is carried out in a liquid medium. A sporophyte develops from a diploid zygote.
Meaning. Horsetails are inedible for animals, are weeds of pastures and fields. Horsetail is used in medicine as a diuretic.
Division Ferns
ferns- perennial, often herbaceous plants of forests of the temperate zone (bracken), reservoirs (salvinia) or tree-like, liana, epiphytic inhabitants of the humid tropics. Currently, there are about 10 thousand species.
The fern sporophyte 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 terms of weight and size. Sporangia develop on the underside of the leaf.
From a dispute develops sprout- a small multicellular plate of green color and with rhizoids (an independent plant). Antheridia (male reproductive organs) and archegonia (female reproductive organs) are formed on the growth. The growths of some species are bisexual, while others are unisexual. The antheridium produces spermatozoa, while the archegonium produces eggs. For their merging, the presence of water is necessary. After fertilization, a fern plant develops from the zygote. Thus, the sprout is the sexual generation (gametophyte), and the adult fern plant is the asexual generation (sporophyte). Sexual and asexual generations are separated. Also, ferns are also characterized by vegetative propagation (for example, by branching the rhizome).
Meaning. The role of ancient ferns, as well as horsetails and club mosses, was to form coal deposits and saturate 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 properties in common:
- For the implementation of the sexual process, they need drop-liquid moisture, which limits their distribution.
- The resulting spores are small, contain few nutrients and have poor viability. The same applies to the development of the embryo of spore plants 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 seed plant settlement) contains a supply of nutrients. The seed is a small sporophyte with root, bud and germinal leaves - cotyledons. It contains a 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 produced in male cones (in gymnosperms) or in anthers (in flowering plants). Inside the pollen grain, the microspore divides, and arises male gametophyte, in which male gametes. Male gametes that form inside microspores, as a rule, are devoid of flagella, are not able to actively move, and are called spermatozoa. 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 the entire cycle of their development proceeds on the sporophyte.
The seed plants are gymnosperms(reproduce by seeds, but do not form fruits) and angiosperms(seeds enclosed in fruits).
Department Gymnosperms
In the Gymnosperms section, 6 classes are distinguished: Seed ferns, Cycads, Bennettites, Gnetoves, Ginkgos, Conifers. Of these, the seed ferns and the Bennettiaceae have completely died out. The gymnosperms were most widely distributed at the end of the Paleozoic and in the Mesozoic era. Currently there are about 720 species of gymnosperms. Gymnosperms are represented exclusively by arboreal forms: trees, shrubs, lianas.
Both in nature and in human life, conifers take second place after flowering plants. There are about 560 species of them. These include pine, spruce, larch, fir, cedar, cypress, juniper, etc.
Structure. Conifers have a tap root system. They often contain mycorrhiza. Wood is 90-95% formed by a strong conductive fabric. Among conifers there are deciduous and evergreen species. In deciduous species (larch) leaves are flat and soft. Evergreens(most conifers) leaves are needle-shaped and hard. The stomata are deeply embedded in the leaf tissue, which reduces the evaporation of water. The needles contain vitamin C and release phytoncides.
Reproduction. 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. A cone consists of an axis on which 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 cones. They form pollen. Each dust grain is equipped with two air sacs. Ripe pollen with the help of wind falls on the ovules of female cones, after which their scales tightly close and stick together with resin. The speck of dust remains inside the ovule until the next spring. From pollination to fertilization takes 12-14 months. Pollen germinates, a pollen tube develops from a vegetative cell, and two sperm cells develop from a generative cell. One merges with the egg, and the second dies. An embryo with a supply of nutrients develops from the zygote, and the seed coat forms from the cover of the ovule. After the seeds ripen, the scales of the cones disperse, and the seeds spill out.
Meaning. Conifers are most widely distributed in the temperate zone of the northern hemisphere, where they form the taiga. A person 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 decay. Sequoia and mammoth tree - representatives of cypress - have valuable wood ("mahogany"). Some redwoods reach a height of more than 100 m and an age of 3-4 thousand years. Representatives of cycads are used by humans for food ("breadfruit").
Department Angiosperms (Flowers)
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 the plant matter of 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:
- Appearance flower- an organ that combines the functions of asexual reproduction (spore formation) and sexual reproduction (seed formation).
- Education in the composition of the flower ovaries, containing the ovules (ovules) and protecting them from the adverse effects of the environment.
- Formation from the ovary fetus: The seeds are 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).
- double fertilization, which results in the formation of a diploid embryo and a triploid (and not haploid, as in gymnosperms) endosperm.
- Maximum gametophyte reduction. Male gametophyte - pollen grain - consists of two cells: vegetative and generative, which divides, forming two sperm. The female gametophyte consists of eight cells of the embryo sac, one of which becomes an egg.
- Reproduction and seeds, and vegetative organs.
- 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 the phloem sieve tubes have a segmented structure, satellite cells appear.
- The rapid course of growth and development processes in annual forms.
- big variety of life forms: trees, shrubs, shrubs, shrubs, perennial herbs, annual herbs, etc.
- Can form complex multi-tiered communities due to the wide variety of life forms.
Meaning angiosperms in human life is difficult to overestimate. Almost all cultivated plants belong to this division. The wood of angiosperms is used in industry, construction, paper, furniture, etc. Many flowering plants are used in medicine.
Systematics. Department Angiosperms (Flowers) are divided into two classes: Dicotyledonous and Monocotyledonous. Monocots evolved from dicots and are less numerous. Dicots are distinguished from monocots in a number of ways. There are many exceptions for each feature. The only absolute feature is the structure of the embryo.
Comparative characteristics of the main classes of angiosperms
| sign | Dicotyledonous | monocots |
| The structure of the embryo | The embryo usually has two cotyledons; the embryo is symmetrical - the kidney occupies the apical position, and the cotyledons are located on the sides of the embryo; cotyledons usually germinate above ground | Embryo with one cotyledon; the embryo is asymmetric - the cotyledon occupies the apical position, and the kidney is on the side; cotyledons usually germinate underground |
| leaf structure | Venation is usually reticulate, rarely pinnate or arcuate; leaves usually petiolate, deciduous | Venation is usually parallel or arcuate; leaves usually sessile, non-deciduous |
| root system | Usually rod | Usually fibrous |
| Growth features | There is a cambium: secondary growth is characteristic | Cambium is usually absent: secondary growth is not characteristic |
| 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, less often four-membered, but never five-membered |
Flowering classes are divided into families mainly on the basis of the structure of the flower and fruit. In this case, the flower formula is used.
Class Dicotyledonous includes cruciferous, hazeweed, cucurbitaceae, legumes, rosaceae, nightshade, compositae families.
Class Monocots includes the families Cereals, Liliaceae.
| family name | Number of species | life forms | flower structure | Fetus | Other features | cultivated plants | wild plants |
| Class Dicotyledonous | |||||||
| Cruciferous (cabbage) | 3 thousand species | Mostly herbs, rarely shrubs and dwarf shrubs | H 4 L 4 T 4 P 1. Inflorescence: brush | Pod or pod | The leaves are alternate, many form a basal rosette. Good honey plants. Contain oils (mustard, rapeseed) | Cabbage, radish, turnip, mustard, rapeseed | Colza, shepherd's purse, evening (night violet) |
| Legumes | 17 thousand species | Herbs, shrubs, shrubs, trees | P (5) L 1+2+(2) T (9)+1 P 1 . Petals: sail, 2 oars, boat (from two fused petals). Inflorescences: brush, head | Bean | Leaves are complex. Nodule bacteria on the roots. The seeds are rich in protein | Beans, peas, beans, soybeans, lentils, peanuts | Alfalfa, clover, chin, 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: brush, 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 |
| Nightshade | 2 thousand species | Mostly herbs, less often subshrubs and shrubs | Ch (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 poisonous substances | Potatoes, tomatoes, eggplant | Henbane, dope, belladonna |
| Compositae | 20 thousand species | Most are herbs, 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 simple without stipules | Sunflower, lettuce, Jerusalem artichoke, chicory, asters, dahlias | Dandelion, chamomile, coltsfoot, tansy, yarrow |
| Class Monocots | |||||||
| lily | 2 thousand species | Herbs | O (3)+3 T 3+3 P 1 . Inflorescence: brush | box, berry | The leaves are lance-shaped with parallel venation, 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 of onions. | lily of the valley, aloe |
| cereals | 12 thousand species | Herbs | O (2)+2 T 3 P 1 . | Zernovka | Leaves entire, with parallel venation, mostly vaginal. The stem is hollow inside (straw). Stem growth is intercalated - as a result of cell division at the base of each internode | Wheat, rice, barley, corn, oats, millet, sorghum, sugarcane | Feather grass, wheatgrass, bluegrass |
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