An overview of the animal world. Department of Green Algae - Chlorophyta

This section introduces the higher and lower plants. The development cycles of the main representatives of the Moss, Fern, Gymnosperms and Angiosperms divisions are considered in detail. Particular attention is paid to the classification of flowering plants, brief characteristics of the families are given.

Plant kingdom

General characteristics of the plant kingdom

Number of species: more than 400 thousand.

Plants are a separate kingdom of living organisms. Plant cells contain nuclei (eukaryotes). With rare exceptions, plants feed by creating nutrients in the light from carbon dioxide and water through photosynthesis. Plants usually lead an attached lifestyle, have unlimited growth, and absorb substances in the form of solutions and gases. Their cells contain plastids, have a large central vacuole and a cell membrane containing cellulose. Starch is used as a storage carbohydrate.

Subkingdom Lower plants. Seaweed

Initial level of knowledge: kingdom, eukaryotes, aerobes, thallus, vegetative, sexual and asexual reproduction, gametes

Response plan

• General characteristics of algae
• Body structure
• Breeding features
• Algae departments
• The value of algae in nature and human practice

Number of species. Currently, algologists have described about 100 thousand species of algae.

Algae habitat.

The very name "algae" encodes the main habitat of these organisms. Indeed, most of the algae are inhabitants of fresh and marine reservoirs. They inhabit the water column (phytoplankton) or are attached to the bottom by rhizoids (phytobenthos). However, algae can be found on the soil, in ice, in lichens, and even inside the hair of a sloth!

Algae body structure.

Algae can be unicellular, colonial or multicellular. The body of multicellular algae does not have tissues and organs, consists of the same cells, therefore it is called the thallus, or thallus. Algae cells have a typical plant structure. Plastids in algae are of two types: small disc-shaped (chloroplasts) and large various forms (chromatophores).

Algae lifestyle.

Algae feed autotrophically through photosynthesis. Minerals and water are absorbed by the entire surface of the body. They breathe using oxygen in the air (aerobically). They reproduce vegetatively, asexually and sexually. During vegetative propagation, parts of the thallus are separated. With asexuality, spores are formed in special cells (sporangia), from which organisms similar to the mother's develop. During sexual reproduction, the formation and fusion of sex cells (gametes) occurs. In some algae, during sexual reproduction, there is an alternation of generations (sporophyte and gametophyte).

Variety of algae.

In the sub-kingdom, the Lower Plants secrete eleven divisions of algae. We will consider only three of them.

Department of Green Algae the most extensive on the given time... It contains both unicellular and multicellular forms. All of them differ primarily in the pure green color of their thalli. Scientists believe that it was green algae that became the ancestors higher plants... The representatives of this department are chlamydomonas, chlorella, spirogyra, ulotrix, ulva and others.

Representatives: chlamydomonas, chlorella, ulotrix, spirogyra.

Chlamydomonas is a unicellular green alga. It has two flagella for movement in the water. A light-sensitive eye (stigma) located in a large cup-shaped bright green chromatophore helps to determine the direction of movement. Two small contractile vacuoles are necessary for the cell to remove excess water from the body. In addition to autotrophic nutrition, this amazing alga is capable of absorbing organic particles from the external environment, i.e. heterotrophic nutrition. V favorable conditions(in summer) Chlamydomonas multiplies by spores. The cell loses its flagella and divides. As a result, from four to eight spores with flagella are formed inside. The shell breaks and the spores go out into external environment where they grow into adults. Sexual reproduction takes place in unfavorable conditions (in autumn). Chlamydomonas are widespread in the thickness of fresh water bodies and serve as food for small animals.

Chlorella is a single-celled green alga without flagella. Its chromatophore is cupped. Chlorella, in the process of photosynthesis, forms many organic substances and emits a large amount of oxygen, since it absorbs ten times more solar energy than other plants. In addition, its cells contain many substances useful to humans. These properties have determined the use of chlorella in spacecraft. Chlorella reproduces only asexually. Like Chlamydomonas, it lives in the fresh water column and serves as food for the simplest and other small animals.

Filamentous algae. Ulotrix is ​​an aquatic filamentous alga with an attached lifestyle. The chromatophore is in the form of an open ring.

The genus of Spirogyra. Spirogyra is an aquatic haploid filamentous alga. It does not attach to the bottom of the reservoir. Reproduces sexually. Neighboring strands of opposite sex are located opposite each other. Bridges are formed between adjacent cells. Conjugation occurs.

Representatives department Brown algae - the inhabitants of the seas. Basically, these are large organisms with rhizoids for attachment to the seabed. Among them there are no unicellular and colonial ones. In addition to green chlorophylls, cells contain additional brown pigments that give them a characteristic color. Representatives of the genus kelp are widely known as "seaweed".

Kelp. Representatives of the genus Laminaria are large (up to 20 meters long) perennial algae. They have a leaf-like thallus attached to the bottom by rhizoids. The upper part of the thallus dies off annually. In the seas at a depth of 5-10 meters, kelp form "algal forests", which serve as habitat and food for a large number of species of marine animals. People have long been using kelp for food, as fertilizer, for medical and cosmetic purposes. Kelp cells are capable of accumulating iodine, which is essential for human health.

Most representatives department Red algae Are marine deep-sea organisms. In addition to the usual pigments, red algae have additional blue and red ones. This allows them to carry out photosynthesis at the depth of the reservoir, where little penetrates sunlight... Most red algae have a multicellular highly branched thallus. Agar-agar is obtained from red algae, which is used to make marshmallows, marshmallows, ice cream. Agar was highly appreciated by microbiologists, because it is a good breeding ground for bacteria and fungi in the laboratory. Porphyry is widespread among the representatives.

The value of algae in nature and in human life.

• Producers of organic matter water bodies, serve as food for animals.
• Oxygen is released during photosynthesis.
• In evolution - the ancestors of higher plants.
• They play an essential role in soil formation.
• Eating food such as kelp.
• Fertilizer production.
• Manufacturing of medicines and food supplements containing iodine, bromine.
• Getting agar-agar.
• Biological water purification from pollutants.
• In case of mass reproduction, they can cause damage, causing "water bloom".

New concepts and terms: alternation of generations, chromatophore, chloroplast.
Representatives: chlamydomonas, chlorella, ulotrix, spirogyra, kelp, porphyra.

Questions for consolidation

1. What are the similarities and differences between the cells of bacteria, fungi, plants?
2. What are the characteristics of lower plants?
3. What are the names and what function do the organs of sexual and asexual reproduction perform?

Subkingdom of the Higher Plants

Initial level of knowledge:
plant kingdom, subkingdom, department, reproduction (vegetative, asexual, sexual), genitals (gametangia: archegonia, antheridia), generations (gametophyte, sporophyte), alternation of generations, sporangia, spores, gametes (egg, sperm, sperm), zygote , mitosis, spore germination

Number of species: more than 300 thousand.
Habitat: mostly terrestrial plants, but also aquatic

The body of higher plants has organs. Shoots appear first in evolution - these are stems with leaves and buds. Roots then emerge, which allows for the best attachment to the soil. In the most organized higher plants one can see a seed, a flower, a fruit. These organs are involved in sexual reproduction and are called generative. All organs of higher plants are composed of tissues. The appearance of tissues and organs is associated with the migration of plants from the aquatic environment to land.

Organs. Vegetative organs. Shoots and roots are vegetative organs (organs that feed and breathe plants). The shoot is an organ of air nutrition (photosynthesis). The root is an organ of soil nutrition (it absorbs water with minerals from the soil).

Reproduction: vegetative (by parts of vegetative organs or modified vegetative organs) and sexual.

Generative organs- organs that perform the functions of sexual reproduction. During sexual reproduction, there is an alternation of generations: gametophyte and sporophyte, which differ in size, life expectancy, and development of organs and tissues. Gametangia are multicellular. Gametes are immobile (eggs, sperm) or motile (sperm).

Spore and seed plants. Higher plants can be divided into two groups: spore and seed.

Spore plants are spread by spores. They form gametangia with gametes and sporangia with spores. Fertilization requires water.

Seed plants are spread using seeds. The function of generative organs in gymnosperms is performed by cones, and in angiosperms - by flowers. No water is needed for fertilization. They have a new process - pollination. In angiosperms, double fertilization is carried out.

Departments of Higher Plants

1. Mossy;
2. Lyciformes;
3. Horsetail;
4. Fern-like;
5. Gymnosperms;
6. Angiosperms.

New concepts and terms: tissues (integumentary, conductive, mechanical, suction, photosynthetic, educational); organs (vegetative: shoot and root, generative); plants: higher, spore, seed: nutrition (soil, air); pollination.

Questions for consolidation.

1. What is the difference between higher plants and lower ones?
2. What tissues are formed in higher plants?
3. What is the difference between vegetative and generative organs?
4. What is the difference between spore and seed plants?
5. What departments are included in the subkingdom of the Higher Plants?

Mossy Division

Initial level of knowledge:
higher plants, vegetative organs: shoot and root, rhizoids, gametophyte, sporophyte, gametangia (antheridia, archegonia), gametes (egg, sperm), zygote, fertilization, sporangia, spores, alternation of generations, mitosis, meiosis, reproduction, vegetative sexual reproduction, spore germination, thallus (thallus), haploid, diploid

Response plan:

• The structure of the body of mosses
• The development cycle of mosses on the example of Kukushkin's flax
• Features of mosses of the genus Sfagnum
• Role in nature and human practice

Number of species. Currently, bryologists have described about 20 thousand species of mosses.

Moss habitat.

Mosses are found on all continents, even in Antarctica. They settle on soil, rocks, stumps, trees, preferring shaded damp places.

The structure of the body of mosses.

Mosses are low-growing herbaceous plants. The body of mosses is either divided into a stem and small leaves (sphagnum, cuckoo flax), or is represented by a thallus, not divided into organs (marshantia). They have no real roots. They are attached to the soil with the help of thin filamentous outgrowths - rhizoids.

Moss lifestyle.

Mosses feed by creating organic matter for themselves in the light in the process of photosynthesis (autotrophically). They absorb water over the entire surface of the body. Breathe using atmospheric oxygen (aerobically).

The development of mosses is very interesting. On some blades of grass, male cells with flagella are formed. On other blades of grass, at the very tops, large female cells mature. During rain or fog, mobile male cells in a drop of water rush to female cells and merge on them. A fertilized female cell (zygote) begins to develop into an amazing structure - a box with a leg. The leg has a sole through which, like through a bridge, nutrients from a blade of grass enter the box. And what happens at this time inside the box? Let's take a look. A huge number of spores are formed in the capsule. Each spore is smaller than a grain of semolina. When the spores mature, the lid opens at the capsule, or small pores form in it, through which the spores fly out. Once in favorable conditions, the spore grows into a thin thread, on which you can soon see young green blades of grass with small rhizoids.

Mosses can be propagated by plant parts or by special buds, i.e. vegetatively.

The variety of mosses.

Among mosses, there are representatives in which the body is not divided into organs, but is represented by the thallus. An example is marching. This moss settles in fires and contributes to the overgrowing of burnt and soil without vegetation.

One of the most common mosses in our country is Kukushkin flax. It grows in forests and swamps, forming dense dense clusters called turf. Kukushkin flax is involved in soil formation and can cause waterlogging of habitats.

Peat moss (sphagnum) grows in swamps, in the tundra, in wet forests... Its stems branch out, growing at the top by three centimeters per year. At the same time, its lower part dies off and forms peat.

The value of mosses in nature and in human life

• Mosses often settle in areas that are inaccessible to other plants. In this case, following lichens, they play an important role in soil formation.
• Mosses are involved in the regulation of the water balance of the forest. They prevent the evaporation of moisture from the soil.
• By storing water, mosses can cause waterlogging.
• In meadows, mosses prevent seed regeneration of grasses, in forests - the germination of tree seeds.
• Peat is widely used in human economic activity. It is used as fuel, pet bedding, fertilizer. You can get wax, paraffin, paints from peat, make paper and cardboard. In construction, peat is used as a heat-insulating material.

New concepts and terms: gametophyte and sporophyte of mosses. peat, waterlogging.

Representatives: p. Kukushkin flax, b. Sphagnum, r. Marching.

Questions for consolidation.

1. What is the systematic position of mosses among higher plants?
2. How can the female gametophyte of the cuckoo flax be distinguished from the male in summer?
3. Why are mosses found only in humid places?
4. It is believed that mosses represent a dead-end branch in evolution. With what it can be connected?
5. Why in peat bogs find the corpses of long-dead animals?

Fern Division

Initial level of knowledge:
kingdom, subkingdom, department, higher plants, rhizome, shortened shoot, adventitious roots, sporophyte, gametophyte, antheridium, archegonium, spore, sporangium, ovum, sperm, zygote, mitosis, meiosis, sexual and vegetative reproduction, fertilization

Response plan:

• Fern habitat.
• Fern sporophyte structure.
• Reproduction of ferns.
• Role in nature and economic value of ferns

Number of species. Currently, scientists have described about 25 thousand species of ferns.

Fern habitat.

Ferns are widespread throughout the globe... They grow in forests, swamps, rivers and lakes, in crevices of rocks, even on the branches of large trees. The greatest variety of ferns can be seen where it is warm and damp - in the tropics and subtropics.

Fern body structure.

Ferns have leaves, stems, and roots. Most of the ferns growing in the forests of our country, the leaves are unusually beautiful, have openwork dissected patterns. When young leaves are born, they are twisted in a spiral, like snails, and then spread out. Fern leaves are also surprised by the fact that they not only photosynthesize, but also form spores on the underside of their plate. No wonder scientists gave the fern leaves their own name - frond (from the Greek "palm branch"). The fronds attach to the stem, which forms a perennial rhizome underground. Well-developed fern roots extend from the rhizome. Pay attention to the "botanical trap": the rhizome is not a huge root, but an underground shoot. In tree ferns, the stem is tall and lignified, and in aquatic ferns (salvinia) it is shortened, almost invisible.

Ferns lifestyle.

Ferns feed on, forming organic matter for themselves in the light in the process of photosynthesis, they absorb from the soil minerals and water with roots. Breathe using oxygen in the air.

Let us consider the development cycle of ferns using the example of the male fern, which is widespread in our forests. In early summer, sporangia form on the underside of the frond. They are collected in groups called soruses. Within the sporangia, haploid spores form, which are dispersed by the wind. The number of spores per plant can be as high as a billion. In some ferns, spores are not uniform in size.

In favorable conditions, the spore grows into a small green heart-shaped plate measuring 1 square meter. see This is a gametophyte of a fern, which is called a sprout. It is attached to the soil by rhizoids. The germ is bisexual, that is, both antheridia and archegonia are formed on it. Fertilization takes place in the aquatic environment. A young sporophyte sprouts from the zygote, feeding at the expense of the overgrowth at first. Vegetative propagation occurs with the help of parts of the rhizome and with the help of brood buds formed on the leaves.

Fronds in ferns growing in temperate climates turn yellow and die off in the fall.

Ferns are capable of reproduction by parts of the rhizome, that is, vegetatively.

The diversity and significance of ferns in nature and in human life.

• Ferns are an important component of many plant communities. They create not only organic matter and oxygen, but also a special microclimate in the forest.

• Ancient tree ferns played important role in the formation of coal. Today, tree ferns are found in the tropics.
• Young frond of bracken fern are eaten as a salad.
• Ferns such as Asplenium are used as ornamental plants.

• Some types of ferns are used in medicine for the treatment of open wounds, coughs, throat diseases, as an anthelmintic (male fern).
• Some species (azolla) are used as a green fertilizer that enriches the soil with nitrogen.

Questions for consolidation.

1. What conditions are necessary for ferns to reproduce?
2. Describe the complications in the structure of ferns compared to mosses.
3. Do you agree with the statement that the fern is a typical land plant?
4. Is it possible to determine whether a fern is male or female by studying its fronds?
5. In what industries does a person use ferns?

Department of Gymnosperms

Initial level of knowledge:
kingdom, subkingdom, department, class, family, sexual and vegetative reproduction, alternation of generations, sporophyte, gametophyte (male and female), sporophyte, sporangium, spore, archegonium, antheridium, gametes, (egg cell, spermatozoon, spore-bearing spike, higher plants, meiosis, mitosis, vegetative and generative organs

Response plan

• Features of seed plants. Features of gymnosperms.
• The structure of conifers.
• Vegetative and sexual reproduction of gymnosperms (for example, Scots pine).
• Role in nature and economic value. Features of seed plants

Seed plants are the most thriving group of terrestrial plants. They descended from heterogeneous ferns.

Characteristics of gymnosperms
Number of species: about 700.
Habitat: gymnosperms grow all over the world. The greatest species diversity is observed along the banks The Pacific, in Australia, New Zealand, in the temperate and cold zones of the Northern Hemisphere. They occupy vast territories, forming coniferous forests. Most species (about 600) are in the class Conifers.
Structure: Gymnosperms - mainly evergreen trees and shrubs with perennial trunks (or trunks), crown, tap root system from the main, lateral and adventitious roots. Needle-shaped leaves (needles) scaly or large flat of various shapes.
Reproduction: Sexual predominates, but vegetative propagation is also possible (by layering, root shoots). Sexual reproduction occurs with alternation of generations. The sporophyte predominates, the gametophyte consists of only a few cells and forms within the sporangia.
Sexual reproduction of Scots pine. At the top of young shoots, female cones are formed. They consist of an axis on which the seed scales are located. On the scales are two sporangia, called ovules (ovules). The ovule consists of integument and nucellus. One cell of nucellus is divided by meiosis, and four spores are formed from it. Three of them die off, and one divides, resulting in the formation of a female gametophyte. It consists of endosperm cells, in which two archegonia are immersed, each containing one egg. Thus, the female gametophyte of pine is surrounded by nucellus cells and sporangium (ovule) integuments.
Male cones are found at the base of young shoots. They consist of an axis, scales and sporangia (anthers), on the scales are two anthers. Numerous spores are formed from the inner cells of the anther by meiosis. Male gametophytes are formed from the spores. The formed gametophyte consists of two cells. One cell (vegetative) is large, has two shells: the outer one is dense and the inner one is thin. A small generative cell is located inside the vegetative cell. The male gametophyte is called pollen. It has two air sacs to facilitate wind transfer.
The anthers rupture, and the pollen is carried by the wind to the female cones, which are open at this time. The pollen falls on the hole in the integument of the kidney. After that, the scales close (the bump closes), soaked in resin. Male bumps dry up. These processes take place in the spring.
In the spring of the following year, a pollen tube is formed from the pollen vegetative cell: a thin inner shell protrudes through holes in the outer shell. The tube grows, passes through a hole in the integument of the ovule, and enters the endosperm. The generative cell divides, and two sperm are formed from it - male gametes without flagella. Sperm travel down the pollen tube. One of them fuses with the egg, and the second sperm and the second egg die.
After fertilization, the female cones turn bright green, inside them seeds are formed from the ovules.
The embryo of a new sporophyte develops from the zygote. The endosperm of the female gametophyte grows, is enriched with nutrients and becomes the storage tissue of the seed. Its substances will be used by the embryo during the germination of the seed. During the formation of the embryo and endosperm, the nucellus is destroyed, and the integument of the ovule turns into a seed coat.
Seed formation takes place under the protection of female cone scales, which gradually change color from green to brown. Then the scales are folded back, and the ripe seeds, equipped with a wing, are carried by the wind. Seed dispersion takes place in winter.
Pine does not propagate vegetatively.

• They are forest forming agents.
• The seeds are used for human and animal food.
• The formation of large amounts of oxygen in the process of photosynthesis.
• Wood is used in shipbuilding, for the manufacture of furniture, building materials.
• In medicine, for the production of camphor, balms, baby powder.
• When distilling wood, resin, rosin, turpentine are obtained.
• Used as fuel.
• Used as ornamental plants.

New concepts and terms: male and female cones, seed scales, ovule (ovule), integument, nucellus, endosperm, anther, pollen, vegetative and generative cells, sperm, pollen tube, seed, seed coat, embryo, pollen shell, seed plants , pollination.

Representatives: amazing velvichia, thuja, cypress, juniper. In Kuzbass, representatives of the Conifers family are widespread, such as Scots pine, cedar, Siberian spruce, Siberian fir, Siberian larch.

Questions for consolidation?

1. What is the difference between a spore and a seed?
2. Why are most conifers called evergreens?
3. How to distinguish a male from a female bump?
4. What does the expression "the pine is dusty" mean?
5. What is the seed and parts of the seed from?
6. What set of chromosomes do different parts of the seed have?
7. Why do gymnosperms have this name?

Department of Angiosperms (Flowering) Plants

Initial level of knowledge:
kingdom, subkingdom, department, higher plants, sexual and asexual reproduction, sporophyte. gametophyte, sporangium, gametangium, pollen, ovule (integument, nucellus), spores, gametes (ovum, sperm), pollination, fertilization, seed

Response plan:

• Features of angiosperms, ensuring the dominant position of this group
• Diversity and distribution of angiosperms
• The development cycle of angiosperms. Double fertilization
• Role in nature and economic value

Number of species: about 250 thousand.
Angiosperms, or flowering, plants make up the most perfect and extensive group of higher plants. They have taken a dominant position thanks to a set of advantages.

• The presence of a flower that protects against external conditions sporangia and gametophytes.
• Double fertilization, providing a large supply of nutrients.
• The seeds develop under the protection of the pericarp.
• The sporophyte is extremely diverse.
• Perfect tissue structure.

Among the angiosperms there are trees, shrubs, perennial and annual grasses.
Structure: The body of the sporophyte consists of the shoot and root systems. In addition to vegetative, generative organs are formed - flowers, from which fruits with seeds then develop. Reproduction. Both vegetative and sexual reproduction is widespread.
Sexual reproduction: In angiosperms, a special organ is formed - a flower. It is a spore-bearing shoot that has changed in the course of evolution.
On the filaments, anthers are formed - sporangia, where haploid spores are formed due to meiosis. In spores, the nucleus divides by mitosis, as a result of which it turns into a male gametophyte - pollen containing two haploid cells - vegetative and generative. The pollen has a thin inner shell and a thick outer shell. It is formed under the protection of the walls of the sporangium, the pollen sac.
Inside the ovary of the pistil are other sporangia - ovules, consisting of integument and nucellus. One cell of nucellus divides by meiosis, forming four spores. Three spores die, and the fourth forms a female gametophyte called the embryonic sac. Inside the embryo sac is the ovum, in the center is the diploid central nucleus. Thus, the female gametophyte is immersed in nucellus, surrounded by the integument of the ovule, and the ovule is located inside the ovary of the pistil.
After the pollen ripens, the anthers open, the pollen is transferred to the stigma of the pistil. A pollen tube is formed from the vegetative cell, which descends into the ovary of the pistil and penetrates into the ovule, when in contact with the embryonic sac, its tip dissolves. The sperm gets inside. One of them merges with the ovum, forming a zygote, and the second with a diploid nucleus, forming a triploid endosperm.
This method of fertilization was discovered by the Russian scientist Sergei Gavrilovich Navashin in 1898 and called it double fertilization.
After fertilization occurs, the integument of the flower dries up, the ovary of the pistil grows and turns into a pericarp, and the ovule - into a seed. A seed coat is formed from the integument of the ovule, and the embryo of a new sporophyte develops from the zygote. In addition, storage tissue is formed in the seeds - endosperm with a triploid set of chromosomes.

Role in nature and economic importance of angiosperms

• They are producers of organic matter, that is, they serve as the primary source of nutrition.
• Release of oxygen into the atmosphere.
• Form multi-tiered forests and other types of plant communities.
• In the food industry.
• In pharmacology.
• In perfumery.
• As a building material.
• As fuel.
• Decorative meaning.

New concepts and terms: double fertilization, embryonic sac, central nucleus, fetus, pericarp, flower, stamen (filament, anther), pistil (ovary).

Questions for consolidation:

1. Give examples of angiosperms that have taken over different environments.
2. What life forms of flowering plants do you know?
3. What plants does a person use for food, and which ones for medicinal and decorative purposes?
4. What is the essence and meaning of double fertilization?

Initial level of knowledge:
taxa (kingdom, department); the structure of the seed of monocotyledonous and dicotyledonous plants, seed, embryo, endosperm, cotyledon; root system (pivotal, fibrous), simple leaf, complex leaf, venation, flower, perianth

Response plan

• Comparative characteristics of the classes Dicotyledons and Monocotyledons.
• The main features of families of the class Dicotyledonous.

The main features of families of the class Monocotyledonous (cereals, liliaceae)

The department Angiosperms, or Flowering, plants include two classes: Dicotyledonous and Monocotyledonous.
Plants belonging to the class Dicotyledonous have embryos with two cotyledons, a taproot system, a cambium is formed in the roots and stems, their leaves are simple and complex with finger or pinnate venation, flowers are five-membered with a double perianth. There are about 200 thousand species in the class.
Plants belonging to the class Monocotyledons have an embryo with one cotyledon, their root system is fibrous, there is no cambium in the stems and roots, the leaves are simple with arcuate or parallel venation, the perianth is simple, the flowers are three-membered. There are more than 65 thousand species in the class.
Each trait separately cannot determine the belonging of a plant to one of the classes, only the totality of traits will make it possible to correctly classify a plant as Monocotyledonous or Dicotyledonous, since there are cases of atypical structure, i.e. exceptions to the rule.

1. Family name.
2. Features of the flower.
3. Flower formula.
4. Inflorescence.
5. Types of fruits.
6. Pollination method.
7. Representatives.

Family Cruciferous

• * Ch4L4T4 + 2P1
• Inflorescence is a brush.
• The fruit is a pod or pod.
• Insect pollinated.

Representatives: cabbage, radish, turnip, rutabaga, mustard, rapeseed, shepherd's purse, rape, jaundice, levkoy, night beauty.

Solanaceae family

• * H (5) L (5) T5P1
• Inflorescence is a brush.
• The fruit is a berry or a capsule.
• Insect-pollinated, sometimes (potatoes) self-pollinated.

Representatives: black nightshade, tobacco, potatoes, eggplant, tomato, pepper, dope, henbane.

Family Rosaceae

• The flowers are correct, bisexual. The perianth is double. The receptacle often grows, grows together with the bases of chalice, stamens, petals.
• * CH5L5T? P? or * Ch5L5T? P1
• Insect pollinated.

Representatives: apple, pear, plum, raspberry, bird cherry, burnet, cinquefoil, mountain ash, strawberry.

Family Asteraceae

• * L (5) T (5) P1 OR ^ L (5) T (5) P or ^ L (5)
• The fruit is achene.
• Mostly insect pollinated.

Representatives: sunflower, chicory, wormwood, chamomile, cornflower, thousand-peel.

Legumes family

• Herbaceous perennial and annual, trees, shrubs, semi-shrubs.
• ^ H (5) L1, (2), 2 T (9) + 1P1
• The fruit is a bean.
• Most legumes have bacterial nodules on their roots.

Representatives: alfalfa, clover, soybeans, peas, beans, seed peas.

Family Cereals

• Herbs
• ^ O3TzP1
• The fruit is a weevil.
• Most are wind-pollinated.

Representatives: rice, corn, wheat, barley, timothy, foxtail, bamboo.

Liliaceae family

• * L3 + 3T6P1
• Inflorescence - brush, umbrella
• Fruit - box or berry
• Insect pollinated.

Representatives: lily of the valley, onion, garlic, asparagus, tulip, lily, hyacinth.

New concepts and terms: Monocotyledonous and Dicotyledonous plants, families Cruciferous, Solanaceae, Rosaceae, Compositae, Legumes, Cereals, Liliaceae; tubular, ligulate and funnel-shaped flowers, stem - straw, flower scales, films.

Questions for consolidation

1. What are the characteristics of plants of the Dicotyledonous class?
2. What are the characteristics of plants of the class Mono-lobed?
3. Give brief description the main families of Dicotyledonous plants.

Classification of flowering plants

Department of Angiosperms, or Flowering

Plants include two classes: Dicotyledonous and Monocotyledonous.

Plants belonging to the class Dicotyledonous have embryos with two cotyledons, a taproot system, a cambium is formed in the roots and stems, their leaves are simple and complex with finger or pinnate venation, flowers are five-membered with a double perianth. There are about 200 thousand species in the class.

Plants belonging to the class Monocots have an embryo with one cotyledon, their root system is fibrous, there is no cambium in the stems and roots, the leaves are simple with arcuate or parallel venation, the perianth is simple, the flowers are three-membered. There are more than 65 thousand species in the class.

Each trait separately cannot determine the belonging of a plant to one of the classes, only the totality of traits will make it possible to correctly classify a plant as Monocotyledonous or Dicotyledonous, since there are cases of atypical structure, i.e. exceptions to the rule.

Family characteristic plan

1. Family name.
2. Life form (trees, shrubs, or grasses).
3. Features of the flower.
4. Flower formula.
5. Inflorescence.
6. Types of fruits.
7. Pollination method.
8. Representatives.

Family Cruciferous

• Annual and perennial grasses, shrubs.
• The flowers are bisexual. The perianth is double.
• * H 4 L 4 T 4 + 2 P 1
• Inflorescence is a brush.
• The fruit is a pod or pod.
• Insect pollinated.

Representatives: cabbage, radish, turnip, rutabaga, mustard, rapeseed, shepherd's purse, rape, jaundice, levkoy, night beauty.

Solanaceae family

• Herbs, less often semi-shrubs, shrubs.
• Corolla is spliced, tubular. Flowers can be right or wrong.
• * H (5) L (5) T 5 P 1
• Inflorescence is a brush.
• The fruit is a berry or a capsule.
• Insect-pollinated, sometimes (potatoes) self-pollinated.

Representatives: black nightshade, tobacco, potatoes, eggplant, tomato, pepper, dope, henbane.

Family Rosaceae

• Trees, shrubs, shrubs and grasses.
• The flowers are correct, bisexual. The perianth is double. The receptacle often grows, grows together with the bases of sepals, stamens, petals.
• * H 5 L 5 T ∞ P ∞ or * H 5 L 5 T ∞ P 1
• Inflorescence - brush, scutellum, umbrella.
• Fruits - drupes, polystyanka, manynuts, apples.
• Insect pollinated.

Representatives: apple, pear, plum, raspberry, bird cherry, burnet, cinquefoil, mountain ash, strawberry.

Family Asteraceae

• Annual and perennial herbs. In the tropics - vines, shrubs, trees.
• There are three types of flowers that make up the baskets - tubular, ligulate, funnel-shaped.
• * L (5) T (5) P 1 OR L (5) T (5) P or L (5)
• The inflorescence is a basket. In most cases, the baskets are an integral part of complex inflorescences - complex panicles, scutes.
• The fruit is achene.
• Mostly insect pollinated.

Representatives: sunflower, chicory, wormwood, chamomile, cornflower, yarrow.

Legumes family

• Herbaceous perennial and annual, trees, shrubs, semi-shrubs.
• The corolla has a sail, oars and a boat.
• H (5) L 1, (2), 2 T (9) +1 P 1
• Inflorescence - brush, panicle, head.
• The fruit is a bean.
• They are insect pollinated, there are self-pollinating ones.
• Most legumes have bacterial nodules on their roots.

Representatives: alfalfa, clover, soybeans, peas, beans, seed peas.

Family Cereals

• Herbs
• Flowers are bisexual, rarely dioecious. The perianth consists of two flower scales and two films - lodicules.
• O 3 T z P 1
• Inflorescence - panicle, compound ear.
• The fruit is a weevil.
• Most are wind-pollinated.
• The stem of all cereals is straw.

Representatives: rice, corn, wheat, barley, timothy, foxtail, bamboo.

Liliaceae family

• Perennial herbaceous bulbous or rhizome plants.
• Perianth simple, accrete or separable
• * L 3 + 3 T 6 P 1
• Inflorescence - brush, umbrella
• Fruit - box or berry
• Insect pollinated.

Representatives: lily of the valley, onion, garlic, asparagus, tulip, lily, hyacinth.

New concepts and terms: Monocotyledonous and Dicotyledonous plants, families Cruciferous, Solanaceous, Rosaceae, Asteraceae, Legumes, Cereals, Liliaceae; tubular, ligulate and funnel-shaped flowers, stem - straw, flower scales, films.

Questions for consolidation

1. What are the characteristics of plants of the Dicotyledonous class?
2. What are the characteristics of plants of the Monocotyledonous class?
3. Give a brief description of the main families of Dicotyledonous plants.
4. Describe the main families of the class Monocots.

Rice. 2. Lake Arakul ()

Or artificial: pond, reservoir, canal (Fig. 4-6).

Rice. 5. Reservoir ()

Whatever the reservoir, natural, artificial, it adorns our land, pleases us with its beauty. In fresh water bodies we take water, which is indispensable neither in everyday life, nor at work. We swim in reservoirs, sunbathe next to them, travel on water on ships, transport goods. The importance of reservoirs in nature is great. Fresh water is essential condition human existence on Earth, and for animals that live in water, this is also the only home. Water contains everything you need for life: light, heat, air and dissolved minerals.

What plants grow and what animals live in fresh water bodies? Once at the reservoir in the warm season, you could only observe those of its inhabitants who live on the surface. But life in the reservoir is everywhere: near the coast, and on the surface, and in the water column, at the very bottom and at the bottom. On the banks of the reservoirs, you can see the leaves and stems of reeds, reeds, cattails, arrowheads. The shallow depth allows these plants to attach to the bottom of the reservoir. At a much greater depth, a white water lily and a yellow water lily grow (Fig. 7, 8). Their flowers and broad leaves float on the smooth surface of the water.

Rice. 7. White water lily ()

Rice. 8. Yellow capsule ()

How did these plants manage to adapt to life in highly moist soil, where there is almost no oxygen? If we consider the cut of the stems of reeds, reeds, cattails, then you can see the air channels that pass in the stems of these plants (Fig. 9, 10).

Rice. 9. Reed ()

Air canals are found in the leaves and roots of aquatic plants. In the white water lily and the yellow petiole pods and the pedicels on which the flowers sit, they are also permeated with air ducts, through which oxygen, necessary for breathing, penetrates. By picking a flower, a person harms the entire plant. Water begins to penetrate into the place of the break in the plant, this leads to rotting of the underwater part and, ultimately, the death of the entire plant.

The duckweed grass in the form of small green plates also floats on the surface of the reservoir, but does not attach to the bottom by roots, and in the water column there are tiny green algae, they can only be seen under a microscope. But their presence betrays the color of the water. When there are a lot of them in the reservoir, the color of the water turns green.

What role do plants play in the lives of numerous inhabitants of water bodies? First, green plants, under the influence of sunlight, take carbon dioxide from the air, and release oxygen into the water, which is necessary for the respiration of all animals. Secondly, in the thickets of the reservoir birds, amphibians, insects and their larvae, fish find refuge and food. Animals in water bodies are everywhere: on the surface and in the water column, on the shore, at the bottom, on aquatic plants. The main links between animals and plants are food. Here water striders (Fig. 11) run swiftly along the surface of the water and hunt mosquitoes and other small animals.

Rice. 11. Water strider ()

Their long legs are covered with fat from below, so the water keeps them. And snails live on aquatic plants: a pond snail and a coil (Fig. 12, 13).

Rice. 12. Pond Snail ()

Without whom the river cannot live? Very small crustaceans of reservoirs, daphnia and cyclops, live and winter in the water. Their value is slightly larger than the comma in the book (Fig. 14, 15).

The most remarkable thing about Daphnia is its long mustache. They will wave their mustaches, drop them sharply, push themselves off the water and jump. The cyclops has an unpaired frontal ocellus, from which it got its name.

The river cannot live without crustaceans, as they purify the water from bacteria, green algae and tiny animals invisible to the eye, if not for crustaceans, the river would quickly overflow with them. Daphnia and Cyclops, like other inhabitants of the river, feed on these organisms, thereby purifying the water. Themselves serve as food for fish fry, molluscs, tadpoles, insect larvae.

Is it possible that someone without a head lives in the river? These are mollusks, toothless and pearl barley (Fig. 16).

Rice. 16 Shellfish ()

First, the shell, consisting of two longitudinal plates, will lie motionless, then its flaps will open slightly and a leg will stick out of it, neither the toothless nor the pearl barley has a head. The toothless will extend its leg and stick it into the sand, the shell will budge. The toothless will move 2-3 centimeters, rest - and again on the road. So it travels along the bottom of the river. Toothless gets food and air directly from water. It will slightly open the flaps of the sink and begin to draw in water, then throw it out. The water is full of the smallest animals, they fall into the shell, so the toothless holds them with special devices. The toothless breathes and eats, and at the same time cleans the water. And pearl barley also works. Each one cleans about 40-50 liters of water per day. Shellfish, insect larvae, tadpoles are eaten by fish, storks, waders, ducks. The swimming beetle hunts other insects, as well as worms, snails, tadpoles. Frogs feed in the coastal parts of water bodies, mainly by flying insects, and they themselves are food for newts and predatory fish, perch and pike. Herons, gulls, kingfishers hunt for fish and newts.

The main food of cancer is vegetable. But he willingly eats animals, as well as the remains of dead animals. Therefore, crayfish are often called the orderlies of reservoirs (Fig. 17).

Cancers change their shells during their life. The sensory organs of the crayfish are well developed, the eyes are pushed forward on thin stalks and consist of a huge number, 3000, tiny eyes. A short pair of antennae are the organs of smell, and the long ones are the sense of touch. If the predator grabs the crayfish by the claw, then the crayfish breaks it off and hides in the burrow. The lost claw will grow back. Crayfish are very sensitive to water pollution, therefore, in the places where they live, they talk about the ecological purity of water bodies.

By the river you can see different dragonflies: beauty, arrow, lute, they live by the river all the time (Fig. 18).

Rice. 18. Dragonfly ()

All dragonflies need water, because only there can their larvae live. The larvae do not look like adult dragonflies, only their eyes are the same. Each eye consists of nearly 30,000 tiny ocelli (Fig. 19).

Rice. 19. Dragonfly larva ()

Both eyes are protruding, due to which the dragonfly can simultaneously look in all directions (Fig. 20). All dragonflies are predators, they hunt in the air, grab insects on the fly.

Rice. 20. Dragonfly eyes ()

The dragonfly larva, after catching the prey, throws forward a strongly elongated lower lip. Usually the lips are folded and covers the head like a mask. The larva sucks water into a large muscle sac inside the body, and then throws it out by force. It turns out a water shot. After a year, and some after 3, the larvae get out to the surface, the skin of the larva bursts, and a dragonfly appears from it. He will sit for several hours, spread his wings and fly away.

Who lives in a drop of water? If you look through a microscope, an amazing world will open unusual creatures... Here is an almost transparent lump that changes all the time - this is an amoeba (Fig. 21).

Other creatures resemble tiny shoes, as they are called. The body of the shoe is covered with cilia, each skillfully controls these cilia and swims quickly (Fig. 22).

Rice. 22. Shoe ()

Trumpeters are the most beautiful inhabitants of the drop, blue, green, like bindweed flowers (Fig. 23).

The trumpeters move slowly and only forward. If something scares them, then they shrink and resemble balls. Amoebas, slippers and trumpeters are single-celled organisms that feed on bacteria.

Predators also live in a drop of water. This is Didinius (Fig. 24).

Although he is smaller than a shoe, he not only boldly attacks it, but also swallows it whole, swelling like a ball.

Plants, animals, bacteria live together in a fresh water body, all of them are well adapted to life in water and are interconnected by food chains. When plants and animals die, they accumulate at the bottom of reservoirs, under the action of bacteria, they are destroyed and turn into salts, which dissolve in water and are used by other animals. The body of water is natural community.

Today in the lesson you got a new idea of ​​the freshwater reservoir as a freshwater community and got acquainted with its inhabitants.

Bibliography

1. Vakhrushev A.A., Danilov D.D. The world 3. - M .: Ballas.
2. Dmitrieva N.Ya., Kazakov A.N. The World Around 3. - M .: Publishing House "Fedorov".
3. Pleshakov A.A. The world around us 3. - M .: Enlightenment.

1. Makuha.ru ().
2. Youtube.com ().
3. Sbio.info ().

Homework

1. What fresh water bodies do you know?
2. What animals can be found in water bodies?
3. Why is it said that a body of water is a natural community?

When planning a walk to the banks of a river, pond or lake, do not forget to bring your camera, sketchbook or sketchbook. There are so many things that deserve attention at the reservoir! Scurrying flocks of small fish, frogs and toads scurrying back and forth, dense thickets reeds. Even the banal ooze that usually covers the surface of ponds is an interesting organism that deserves attention. Having scooped it up and making out the thinnest threads, remember that mud is a multicellular alga called spirogyra. By placing the sample under a microscope, you will see an interesting structure.

What can be seen on the shore of the reservoir

The fauna of the pond is striking in its diversity. On its shores overgrown with water lilies, you can often see a butterfly with light yellow wings covered with brown lines. Know - you met with a water lily (or marsh) moth. This butterfly lays its testicles on the leaves of aquatic plants.

If you notice on the surface of the water surface of the pond tiny floating shuttles with small "noses" extended upward, you should know that each of these shuttles is a cocoon of a beetle called the water lover. Water loving beetles are among the largest beetles, their size is up to 40 mm in length. They leisurely swim or crawl on the surface of underwater plants.

Occasionally, in loose, moist soil, you can see a large brown-yellow insect, reaching a length of about 5 cm.It is covered with small silky-looking hairs and looks quite intimidating. We are talking about a bear - an underground inhabitant, absolutely not dangerous to humans. The constant occupation of the bear is digging tunnels in the ground, which causes damage to the plants.

Freshwater snails are also found in reservoirs, and many others, sometimes extremely interesting representatives natural kingdom.

Amazing metamorphosis

We all know from childhood that frogs are obtained from tadpoles - larvae living in the water of fresh water bodies, able to breathe with gills and floating thanks to the tail, which is actually a fin. But when a tiny specimen matures and turns into an adult frog, a wonderful metamorphosis occurs - the frog is able to breathe with its lungs, it lives on land and moves along its surface with the help of its legs.

Like amphibians, some insects lay eggs in the aquatic environment and their larvae develop there. But in adulthood, they move into another - air - habitat.

Sometimes, on hot days in mid-summer, at sunset, a phenomenon is observed that is somewhat similar to a snowstorm. Mayflies are circling. Already from the name it is clear that the mayfly does not live long - a day or two, no more. Although its larvae live in underwater world more than two years.

About the same - within a year or more - dragonfly larvae ripen in the aquatic environment. Like dragonflies, wingless aquatic larvae or pupae of mosquitoes, stoneflies, caddis flies, foldflies and even individual butterflies belonging to the moth family turn into flying insects.

A lot of plants observed on the shores of fresh water bodies are capable of living both surface and underwater lifestyles. Their lower part is submerged in water, and the upper part is located on the surface. Different living conditions lead to the appearance of separate leaf forms in such plants. An example is the water buttercup. Its air and underwater leaves have a different structure.

Plants and animals of water bodies - living barometers

One of the most beautiful plants in Central Russian reservoirs is the white water lily. Its flowers float up and open in the morning (about 7 o'clock). In the evenings - around five or six o'clock - the water lily closes its flowers again and hides them under the water.

For a long time, a popular omen says that if in the morning a water lily is in no hurry to show its flowers or hides them ahead of time, you should wait for rain. Thus, this wonderful flower serves as a reliable natural barometer, all the time of its flowering regularly carrying the "weather service".

Another reliable weather forecaster is a plant called calla calla. It received this name in connection with its large wide leaves (from the inside they are white), covering the inflorescences like wings. On the eve of good weather, the "wings" stand upright, they can be clearly seen from afar. Before bad weather, they sag.

Most species of animals in water bodies are no less sensitive to the slightest changes in the weather. Before bad weather, crayfish crawl out of the water, leeches appear. Whole line popular signs associates the characteristic behavior of frogs with a change in the weather.

Many species of benthic fish - catfish, loaches, loaches - are quite susceptible to changes in barometer pressure. Their usual behavior is calm movement and lying at the bottom. But before the onset of bad weather, loaches tend to rise closer to the surface, and loach begins to rush in different directions.

On a quiet warm evening, appearing on the reedy bank of a pond or a shallow stream, you will hear a melodic subtle ringing. Where is he from? Its source is the swarming hordes of mosquitoes called tolkuns. Their cloud winds in the air in the form of a pillar, sometimes falls sharply downward or soars upward. They swarm only in stable clear weather.

About waterlogging of reservoirs

Sometimes in a river backwater, in a pond or lake, the current is very weak or completely absent. Then plants appear in these places and over time a shallow body of water can completely overgrow and become swamped with coastal mosses - green and peat (sphagnum), capable of forming whole moss bogs. Sphagnum belongs to especially moisture-loving plants of water bodies. If we examine its structure under a microscope, we will see that its stems and leaves consist mainly of transparent large cells filled with air and capable of quickly and easily absorbing water.

A fur carpet serves as an excellent breeding ground for herbaceous plants - saber, watch, cranberry, cotton grass. Behind them, you should wait for the appearance of marsh bushes - andromeda, cassandra.

In the process of dying off, parts of the plants sink to the bottom, where they accumulate year after year with the formation of peat. Peat of sphagnum origin is formed very, very slowly. It takes a time period of the order of a thousand years to accumulate a meter-thick layer.

Swamps are formed not only due to the attack on water bodies of plants. Another way of their appearance is swamping of forests, meadows, forest burns and clearings. There are several types of swamps - they can be lowland, upland, transitional. Each of them implies its own special natural conditions. That is why, when mentioning the flora and fauna of swamps, as well as other bodies of water, we always mean their unusual diversity.

Let's take a drop of water from a pond and place it under a microscope. You will be surprised - this is a whole world in which life is in full swing! In the space of one drop, many tiny organisms, consisting of one cell, are moving briskly and scurrying back and forth. It is from here that their name is - the simplest unicellular. The smallest of them are on the order of thousandths of a millimeter.

What are these inhabitants? First of all, those familiar to everyone from school course ciliates floating afloat with their numerous cilia. Most often you can find the so-called ciliate shoe. The name comes from the shape of the body, vaguely reminiscent of the footprint of a shoe. The size of the ciliate shoe is relatively large. It is about 0.2 mm long.

Other microscopic animals of water bodies that can be seen through the eyepiece of a microscope are unicellular flagellates. The two most common representatives of this species are called armored ceratium and euglena green - a microscopic organism no more than 0.05 mm long.

Perhaps everyone knows the phenomenon called water bloom, when the reservoir turns green before our eyes. This indicates the rapid development in the aquatic environment of a single-celled microscopic green alga called chlamydomonas, the size of which is 0.01-0.03 mm. In addition to it, we will find in a drop of water and different types amoebas, the largest of which reach a size of 0.5 mm.

If the magnification is strong, you will also see tiny green balls. This is a single-celled algae of the smallest size (0.001 mm) called chlorella.

Let's dive to the bottom

Sometimes, when looking at the bottom of a reservoir, you can find small lines or grooves, as if drawn with a stick. These are traces left from the movement of large shells that live in domestic water bodies - toothless and pearl barley. In appearance, these animals of reservoirs are very similar, but differ in the shape of the shell. In the toothless, it is more rounded and has no teeth (hence the name).

Another permanent resident of the bottom area is a small worm called a tubule. It is named so because of the ability to hide a part of the body in a nest in the form of a tube, which is dug out in the ground. Sometimes, with a large accumulation of tubifex, the bottom can acquire a bright red color.

If the water is clear and clean, then a frequent inhabitant of the bottom is a sculpting goby. He usually hides between stones, which is why he is called so.

Back to the surface

If you look closely at the surface of a pond or river backwater, you will surely see small, long-legged insects sliding along the surface in sharp jerks, as if measuring space. These are the so-called water striders.

In addition to them, on the surface of the water, you can see spinning groups of small shiny bugs about 5 mm long. These bugs got their name (twirls) for their constant movement - twisting, writing out spirals and various shapes.

At the surface of the pond, a flock of small fish hunt for insects falling into the water. These are the so-called verkhovki - representatives of the smallest river fish. Each of them is about 5 centimeters long.

If you see a solid green carpet on the surface of a reservoir, be aware that we are talking about the growth of duckweed, which is considered the smallest of the flowering plants in the reservoirs of our country. The duckweed has no leaves. The stalk of the plant is a tiny green cake, from which a thin root leaves and stretches into the water.

Duckweed bloom is rarely observed in the form of tiny flowers with a pinhead in size. The duckweed found in our reservoirs can be of three types - small, humpbacked and three-lobed.

Another free floating plant is vodokras. Its roots dipped into the water do not reach the bottom, but can be connected to each other by a single shoot. Sometimes a breath of wind can carry a whole array of water colors in one direction.

Rare animals in reservoirs

A special way of life is characteristic of the water spider. Among the plants of a stagnant reservoir, he weaves a canopy of cobwebs, then drags air under it, from which the cobweb stretches to form a kind of bell. Air bubbles stick to the hairs on the spider's abdomen and with such a reserve under water, the spider resembles a silver-colored droplet, which is why it is called silver.

Sometimes at the bottom of lakes you can find a freshwater alga called hara. Its peculiarity is its ability to grow in water with a high lime content. Hara extracts lime from the water and deposits it on its own surface, which makes it white.

Another remarkable representative of the world of animal reservoirs, living along the banks of streams and rivulets with clear water, - a bird called a dipper. Its uniqueness lies in the ability to dive under water and even run along the bottom in search of food.

With a detailed study of stagnant or slowly flowing waters, one can find tiny tubes of a brown or greenish color with thin long tentacles covering the leaves and stems of aquatic plants. We are talking about hydras - coelenterates. The body of such a hydra is no more than 10-15 mm long, but its tentacles are much longer. Hydra is not afraid of damage and, when cut across, restores the missing organs and continues to exist. It will survive even when divided into a large number of pieces. This process is called regeneration and takes place among the simplest organisms.

What are wonderful frogs

Frogs and toads are fascinating creatures. At the first glance at the frog it seems that it is in deep thought. But then a fly flashed nearby. With an instant click of the tongue, the insect is quickly caught. The structure of the frog's eyes allows it to see only moving objects that are similar in size to its food.

In addition to frogs, in any swampy place you can find a snake, and sometimes a viper - perhaps the most dangerous of animals living in water bodies. Its bite is fatal, but the poison can be used in medicinal purposes- as a raw material for obtaining a medicine.

Live pharmacy

If we talk about the medical properties of the inhabitants of the pond, one cannot fail to mention the leeches used by doctors for a long time due to their ability to bite through the skin and suck blood in small quantities. That is why they are called medical. They are used today as well. Unlike others freshwater species leeches, the medical one has longitudinal narrow stripes on the back and sides of a yellow-orange color.

For medicinal purposes, badyaga is also used - a freshwater sponge that can settle on the branches and trunks of sunken trees. It is dried, ground into powder and used in our country and in other countries as a means of traditional medicine.

Other medicinal herbs growing on the banks of reservoirs are marsh creeper, water pepper, three-part succession, three-leaf watch, calamus. The leaves and roots of these plants are used as medicinal raw materials.

Birds-builders

Remiz is a bird that lives in our country and has a wonderful art of building a nest. A nest is woven in a tree, at the tip of a thin branch, hanging over the water. Remiz is able to bend a twig with a hoop, braid with plant fluff, which is given the shape of a mitten.

Fish are also capable of building nests and taking care of offspring. For example, it is worth remembering the three-spined stickleback - a small fish of our reservoirs, weighing only 4 g. Male sticklebacks build real nests in the spring. In a sandy bottom with a small current, they dug pits into which blades of grass are dragged and stick together with secreted mucus. It turns out a dense lump in which a through tunnel is made. So the nest is ready for future offspring!

Caddis flies living on land lay their larvae in water and build houses from grains of sand, shells and sticks to protect offspring.

At any natural area you can find a variety of reservoirs - lakes, ponds, reservoirs, etc. All of them, as a rule, are not devoid of plants. Plants often play an important role here, developing in mass near the coast in shallow water, forming extensive underwater thickets at the bottom, and sometimes a continuous cover on the water surface.

The flora of reservoirs is diverse. We find here not only flowering plants, but also some ferns, horsetails, bryophytes. Algae are richly represented. Most of them are small, visible only under a microscope. There are few large ones that are well distinguishable with the naked eye. In the future, considering the flora of water bodies, we will have in mind only those plants that are relatively large in size.

Aquatic plants are also diverse in their position in the reservoir. Some of them are entirely under water, completely submerged (elodea, hornwort, various pondweed). Others are submerged in water only with their lower part (riverine horsetail, lake reed, arrowhead). There are those that float freely on the surface (duckweed, vodokras, salvinia). Finally, some inhabitants of reservoirs have floating leaves, but their rhizome is attached to the bottom (egg capsule, water lily, amphibian mountaineer). We will consider the plants of each of these groups in detail later.

The living conditions of plants in reservoirs are peculiar. There is always enough water here and there is never a shortage of it. Therefore, for the inhabitants of reservoirs, it does not matter how much precipitation falls in a given area - a lot or a little. Aquatic plants are always provided with water and are much less dependent on the climate than terrestrial and terrestrial plants. Many aquatic plants are very widespread - from the northern regions of the country to the extreme south, they are not associated with specific natural zones.

A characteristic feature of the environment in reservoirs is the slow heating of water in spring. Water, which has a high heat capacity, remains cold for a long time in spring, and this is reflected in the development of the inhabitants of reservoirs. Aquatic plants wake up late in spring, much later than terrestrial plants. They begin to develop only when the water warms up enough.

The conditions of oxygen supply are also peculiar in water bodies. Many aquatic plants - those with emergent shoots or floating leaves - require oxygen gas. It enters through the stomata, scattered over the surface of those organs that come into contact with air. This gas penetrates into the underwater organs through special air channels that densely penetrate the entire body of the plant, right down to the rhizomes and roots. An extensive network of the thinnest air channels, numerous air cavities - a characteristic anatomical feature many inhabitants of reservoirs.

The aquatic environment creates specific conditions for seed reproduction of plants. Some aquatic pollen is carried by water. Water also plays an important role in the spread of seeds. Among aquatic plants, there are many that have floating seeds and fruits that can long time stay on the surface without sinking to the bottom. Driven by the wind, they can travel a considerable distance. Of course, currents also carry them over.

Finally, the aquatic environment determines the specifics of overwintering of plants. Only in aquatic plants you can find a special way of overwintering, when special buds overwinter, sinking to the bottom. These buds are called turions. They form at the end of summer, then separate from the mother's body and go under water. In the spring, the buds germinate and give rise to new plants. Many inhabitants of reservoirs winter in the form of rhizomes at the bottom. None of the aquatic plants have living organs in winter on the ice-covered surface of the reservoir.

Let us consider in more detail the individual groups of aquatic plants.

Fully submerged plants are most associated with the aquatic environment. They come into contact with water with the entire surface of their body. Their structure and life are entirely determined by the characteristics of the aquatic environment. Living conditions in water are very different from living conditions on land. Therefore, aquatic plants are in many respects unlike terrestrial ones.

Completely submerged inhabitants of reservoirs receive oxygen, necessary for breathing, and carbon dioxide, necessary for creating organic matter, not from air, but from water. Both of these gases are dissolved in water and are absorbed by the entire surface of the plant's body. Gas solutions penetrate directly through the thin walls of the outer cells. The leaves of these inhabitants of reservoirs are delicate, thin, transparent. They do not have any kind of water retention. They, for example, have a completely undeveloped cuticle - a thin waterproof layer that covers the outside of the leaves of land plants. Protection against water loss is not needed - there is no danger of drying out.

The peculiarity of the life of underwater plants is that they receive mineral nutrients from water, and not from the soil. These substances, dissolved in water, are also absorbed by the entire surface of the body. The roots do not play a significant role here. The root systems of aquatic plants are poorly developed. Their main purpose is to attach the plant to a specific place at the bottom of the reservoir, and not absorb nutrients.

Many completely submerged inhabitants of reservoirs support their shoots in more or less upright position... However, this is achieved in a completely different way than that of the inhabitants of the land. Aquatic plants do not have strong, woody stems, they have almost no developed mechanical tissues that play a strengthening role. The stems of these plants are tender, soft, weak. They rise upward due to the fact that they contain a lot of air in their tissues.

Among the plants completely submerged in water, we often find various types of pondweed in our freshwater bodies. These are flowering plants. They have well-developed stems and leaves, and the plants themselves are usually quite large. However, people who are far from botany often incorrectly call them algae.

Consider, as an example, one of the most common types of pondweed, Potamogeton perfoliatus. This plant has a relatively long stem standing upright in the water, which is attached to the bottom by roots. On the stem, oval-heart-shaped leaves are alternately located. The leaf blades are attached directly to the stem; the leaves have no petioles. Rdest is always submerged in water. Only during the flowering period do the inflorescences of the plant rise above the water surface, similar to short loose ears. Each such inflorescence consists of small nondescript flowers of a yellowish-greenish color, sitting on a common axis. After flowering, the spike-shaped inflorescence goes under water again. The fruits of the plant ripen here.

The leaves of the pondweed are hard to the touch, thickish - they are completely covered from the surface with some kind of bloom. If you take the plant out of the water and drop a ten percent solution of hydrochloric acid on the leaf, violent boiling is observed - a lot of gas bubbles appear, and a slight hiss is heard. All this indicates that the leaves of pondweed are covered with a thin film of lime on the outside. It is she who gives a violent reaction with hydrochloric acid. Lime bloom on the leaves can be observed not only in this type of pondweed, but also in some others (for example, in curly pondweed, shiny, etc.). All these plants live in reservoirs with rather hard water, which contains a significant amount of lime.

Pridest is pierced-leaved; Lesser duckweed - individual plants

Another plant completely submerged in water is Elodea canadensis. This plant is much smaller than pondweed, which is described above. Elodea differs in the arrangement of leaves on the stem - they are collected in three or four, forming numerous whorls. The shape of the leaves is elongated, oblong, they have no petioles. The surface of the leaves, like that of pondweed, is covered with a dirty coating of lime. Elodea stems spread along the bottom, but lie free, do not take root.

Elodea is a flowering plant. But her flowers appear extremely rarely. The plant hardly reproduces by seeds and maintains its existence only by vegetative means. The vegetative propagation capacity of Elodea is amazing. If you cut off the end of the stem and throw it into a vessel in water, then after a few weeks we will find here a long shoot with many leaves (of course, for rapid growth, you need a sufficient amount of light, heat, etc.).

Elodea is a plant widespread in our waters. It is found in almost any lake, pond, and often forms continuous thickets at the bottom. But this is a plant of foreign origin. Homeland of Elodea - North America... In the first half of the last century, the plant accidentally came to Europe and quickly spread there, populating many water bodies. From Western Europe, elodea penetrated into our country. Strong growth of elodea in water bodies is an undesirable phenomenon. This is why this plant is called water plague.

Among the completely submerged plants of fresh water bodies, we also find the original green alga, which is called hara(species of the genus Chara). In appearance, it resembles a horsetail a little - the plant has a vertical main "stem" and lateral thinner "branches" extending from it in all directions. These branches are located on the stem in whorls, several at a time, like a horsetail. Khara is one of our relatively large algae, its stem reaches a height of 20 - 30 cm.

Let us now consider the most important free-floating plants of water bodies.

The most familiar of them is the duckweed (Lemna minor). This very small plant often forms a continuous light green bloom on the surface of water in lakes and ponds. Duckweed thickets consist of many separate flat cakes oval smaller than a nail. These are floating stems of a plant. From the lower surface of each of them, a root with a thickening at the end departs into the water. Under favorable conditions, the duckweed vigorously reproduces vegetatively: from the oval plate, the same other begins to grow from the side, from the other - a third, etc. Daughter specimens soon separate from the mother and begin to lead an independent life. Reproducing rapidly in this way, duckweed in a short time can cover the entire body of water, if it is small.

Duckweed thickets can be seen only in the warm season. Late autumn the plants are gone, the water surface becomes clean. Green cakes by this time die off and sink to the bottom.

Together with them, live duckweed buds are immersed in water, which spend there all winter. In the spring, these buds rise to the surface and give rise to young plants. By the summer, the duckweed manages to grow so much that it covers the entire reservoir.

Duckweed is a flowering plant. But it blooms extremely rarely. Its flowers are so small that it is difficult to see them with the naked eye. The plant maintains its existence through vigorous vegetative reproduction, which we just talked about.

A notable feature of duckweed is the high protein content in its stalks. In terms of protein richness, duckweed can only compete with legumes. The small, inconspicuous plant is a valuable, highly nutritious food for some domestic animals and birds.

In our reservoirs, there is another small plant, which is very similar to duckweed and also floats on the surface of the water. It is called common mulberry(Spirodela polyrrhiza). This plant differs well from duckweed in that it has a bunch of fine hairy roots on the underside of the oval cakes (the roots are best visible when the plant is floating in an aquarium or a glass of water). In duckweed, as we have already said, there is only one root on the underside of the stem.

Another plant, water-paint (Hydrocharis morsus-ranae), floats freely on the surface of water bodies. The leaves of this inhabitant of reservoirs sit on long petioles, have a characteristic oval-heart-shaped shape and are collected in a rosette. A bunch of short roots extends from each outlet into the water. Separate sockets are connected under water by a thin rhizome. When the wind blows, the plant begins to move along the surface of the water, and the rosettes do not change their relative position.

In summer, Vodokras has small flowers with three white petals. Each flower sits at the end of a long peduncle that rises from the center of the leaf rosette. By autumn, at the ends of the thin underwater stalks of the water color, turion buds are formed, which are then separated from the mother's body and sink to the bottom, where they spend the winter. In the spring they float to the surface and give rise to new plants.

On the surface of fresh water bodies located in the southern half of the European part of our country, you can see a free-floating small fern Salvinia natans. This plant is completely different from ordinary ones. forest ferns and is much smaller. From the stem of salvinia, lying on the water, oval leaves, slightly larger than a nail, extend to one side and the other. They are thick, dense, and sit on very short petioles. The leaves, like the stem, float on the surface of the water. Besides these leaves, salvinia has others. They are similar in appearance to roots and extend from the stem down into the water.

Salvinia is very different in appearance from the ferns we are familiar with, but it is similar to them in terms of reproduction. It is for this reason that it is classified as a fern. Of course, a plant never has any flowers.

Let us now turn to those plants in our reservoirs that have floating leaves, but are attached to the bottom and cannot move freely.

The most familiar of these plants is the egg-capsule (Nuphar lutea). Many have seen the beautiful yellow flowers of the capsule. Slightly rising above the surface of the water, they always attract attention with their bright colors. The flower has five large yellow sepals and many small petals of the same color. There are a large number of stamens, and there is only one pistil, its shape is very characteristic - it resembles a round flask with a very short neck. After flowering, the pistil grows, retaining its original shape. Inside the ovary, seeds ripen, immersed in mucus.

The flower pod is located at the end of a long pedicel that grows from the rhizome lying at the bottom of the reservoir. The leaves of the plant are large, dense, with a characteristic rounded heart-shaped shape, with a shiny, glossy surface. They float on water, and the stomata are located only on their upper side (in most land plants, on the lower side). The petioles of the leaves, like the pedicels, are very long. They also originate from the rhizome.

The leaves and flowers of the egg capsule are familiar to many. But few have seen the rhizome of the plant. It surprises with its impressive size. Its thickness is one hand or more, its length is up to one meter. It stores in winter the reserves of nutrients necessary for the formation of leaves and flowers for the next year.

Petioles of leaves, capsules and pedicels, on which flowers sit, are loose, porous. They are densely penetrated with air ducts. As we already know, thanks to these channels, oxygen is supplied to the underwater organs of the plant, which is necessary for breathing. Tearing off leaf petioles or pedicels causes great harm to the egg capsule. Through the place of the break, water begins to penetrate into the plant, and this leads to rotting of the underwater part and, ultimately, to the death of the entire plant. It is better not to pick off the beautiful flowers of the capsule.

Close to the egg capsule in many of its features and white water lily(Nymphaea alba). She has the same thick rhizome lying at the bottom, almost the same leaves - large, glossy, floating on the water. However, the flowers are completely different - pure white, even more beautiful than those of the egg capsule. They have a pleasant delicate aroma. The numerous petals of the flower are directed in different directions and partially cover each other, and the flower itself is somewhat reminiscent of a lush white rose... Water lily flowers float to the surface of the water and open early in the morning. In the evening they close again and hide under the water. But this only happens when the weather is stable and good, when it is sunny and dry. If bad weather approaches, the water lily behaves completely differently - the flowers either do not appear at all from the water, or they hide ahead of time. Therefore, the behavior of the flowers of a given plant can predict the weather.

Many people strive to pluck the beautiful white flowers of a water lily. But this should not be done: the plant may die, since it is very sensitive to wounds. True friend nature must resolutely refrain from collecting water lily flowers and deter others from it.

As already mentioned, among the plants of reservoirs there are those that are only partially submerged in water. Their stems rise above the water for a considerable length. Flowers and most of the leaves are found in the air. In terms of their vital activity and structure, these plants are closer to real terrestrial representatives of the flora than to typical inhabitants of reservoirs, completely submerged in water.

Plants of this type are known to many bulrush(Scirpus lacustris). It often forms solid thickets in the water near the coast. The appearance of this inhabitant of reservoirs is peculiar - a long dark green stem rises above the water, completely devoid of leaves and having a smooth surface. Below, by the water, the stem is thicker than a pencil, upward it becomes thinner and thinner. Its length reaches 1-2 m. In the upper part of the plant, a brownish inflorescence, consisting of several spikelets, departs from the stem.

Lake reed belongs to the sedge family, but outwardly very little resembles sedges.

Reed stems, like many other aquatic plants, are loose, porous. By gripping the stem with two fingers, it can be flattened almost effortlessly. The plant is densely penetrated with a network of air ducts; there is a lot of air in its tissues.

Let's get acquainted now with another plant partially submerged in water. It is called the riverine horsetail (Equisetum fluviatile). This type of horsetail, like the reeds already familiar to us, often forms dense thickets in the coastal part of the reservoir, not far from the coast. These thickets consist of many straight stems that rise fairly high above the water.

It is not difficult to recognize a horsetail: its thin cylindrical stem consists of many segments-segments, and one segment is separated from the other by a belt of small tooth-leaves. We observe the same in the rest of the horsetails. However, the riverine horsetail differs from many of its closest relatives in that its stem for the most part does not give lateral branches. It looks like a thin green twig. In autumn, the stalk of the horsetail dies off, and only a living rhizome hibernates at the bottom of the reservoir. In the spring, new shoots grow from it. These shoots appear above the water surface rather late, at the very end of spring, when the water warms up enough.

Among the plants partially submerged in water, we find the common arrowhead (Sagittaria sagittifolia). It is a flowering plant. Its flowers are quite noticeable, with three rounded white petals. Some flowers are male, containing only stamens, others are female, in which only pistils can be found. Both those and others are located on the same plant, and in a certain order: male in the upper part of the stem, female below. Arrowhead stalks contain white milky sap. If you tear off the flower, then a drop of whitish liquid will soon appear at the rupture site.

The large leaf blades of the arrowhead attract attention with their original shape. The triangular leaf has a deep wedge-shaped notch at the base and looks like a highly enlarged arrowhead. It is because of this that the plant got its name. Sagittal leaf blades more or less rise above the water. They sit at the end of long petioles, most of which are hidden under water. In addition to these well-visible leaves, the plant has others - less noticeable, which are completely submerged in water and never rise above the surface. Their shape is completely different - they look like long green ribbons. Consequently, the arrowhead has two types of leaves - above-water and underwater, and both are very different. We observe similar differences in some other aquatic plants. The reason for these differences is understandable: the leaves immersed in water are in the same environmental conditions, the leaves above the water are in completely different ones. Arrowhead is a perennial plant. Its stem and leaves die off by winter, only the tuberous rhizome at the bottom remains alive.

Of those plants that are submerged in water only with their lower part, we can also mention the Umbelliferae (Butomus umbellatus). During flowering, this plant always attracts attention. It has beautiful white-pink flowers, collected in a loose inflorescence at the top of the stem. There are no leaves on the stem, and therefore the flowers are especially noticeable. Each flower sits at the end of a long stalk, and all these branches come out of the same point and point in different directions.

Susak is probably familiar to many. It is widespread in the reservoirs of our country, found in the North, in Central Russia, in Siberia and other regions. It should be noted that such a wide geographical distribution is characteristic not only of the mongrel, but also of many other aquatic plants. This is typical for them.

If we look at the flower of the susak in detail, we will see that it has three greenish-red sepals, three pinkish petals, nine stamens and six crimson-red pistils. Amazing correctness in the structure of the flower: the number of its parts is a multiple of three. This is typical of monocotyledonous plants, to which the susak belongs.

Susak leaves are very narrow, long, straight. They are collected in a bunch and rise up from the very base of the stem. Interestingly, they are not flat, but triangular. Both the stem and the leaves grow from a thick, fleshy rhizome lying at the bottom of the reservoir.

Susak is notable for the fact that this plant can be used for food. In the recent past, flour was made from its rhizomes, rich in starch, from which bread and flat cakes were baked (this was common, for example, among local residents in Yakutia). Whole rhizomes are also edible, but only baked or fried. Here is an unusual food source to be found at the bottom of water bodies. A kind of "underwater bread".

Special studies have shown that the flour from the rhizomes of the susak has everything that is needed for human nutrition. After all, rhizomes contain not only starch, but quite a lot of protein and even a certain amount of fat. So, in terms of nutritional value, it is even better than our regular bread.

Susak is also useful in that it can serve as a fodder plant for livestock. Its leaves and stems are readily eaten by pets.

In our reservoirs, there are many plants, similar to the sushak, in which the lower part of the plant is in the water, and the upper part is above the water. We have talked about not all plants of this type. These include, for example, various types of chastuha, head-heads, etc.

The animal world is represented on Earth by a huge variety. Currently, there are over 1.5 million different species of animals.

Animals are living organisms that have much in common with plants in structure and life. However, there are also significant differences between them. Plants are characterized by growth throughout their life, and in animals, their final size is formed after a certain period of growth. Plants for the most part are motionless, lead an attached lifestyle; animals, on the other hand, actively move in search of food. The main difference between animals and plants is the different ways of feeding. Plants create organic matter; animals live off plants and other animals, as they feed on ready-made organic matter... Another important feature of animals is associated with mobility - their cells are devoid of an outer hard shell.

To get an idea of ​​the animal world as a whole, one must turn to classification (as in the study of plants). The system of the animal world developed by zoologists consists of species, genera, families, orders, classes and types. The types of protozoa, coelenterates, worms (flat, round, annelids), mollusks, arthropods are combined into the department of invertebrates. The type of chordates (vertebrates) is represented by several classes of animals.

Invertebrates. All of them are characterized by the fact that they do not have an internal skeleton, a spine. The world of these animals is divided into two halves: unicellular and multicellular. Single-celled animals are represented by a single type - protozoa.

Type Intestinal. In the process of the development of the animal world, multicellular animals appeared on Earth, the oldest representatives of which are coelenterates. The body of this type of animal consists of many cells arranged in two layers. The groups of cells in these layers perform different functions. Many representatives have a skeleton located between two layers.

Cnidarians live exclusively in water, mainly in the seas and oceans (jellyfish, sea anemones, coral). In fresh water middle lane you can also find a representative of this type - hydra. Most of these animals are sedentary. The oral opening of the coelenterates is equipped with tentacles on which stinging, or nettle, cells are located. Animals paralyze their prey with them, and also defend themselves from enemies.

Ringed worms are characterized by an even higher level of development. The body of these worms is segmented, dissected into homogeneous parts. For the first time in the history of the animal kingdom, annelids appear circulatory system... The nervous and excretory systems are well developed.

A typical annelid is the earthworm. He has well-developed musculature, which, by contraction, allows him to move. Earthworms have no special respiratory organs. This function is performed by the skin. Earthworms, passing the soil through their body, improve its chemical composition, fertility, loosen, plow it.

Shellfish type. Further complication of organ systems is presented in the structure of molluscs. The body of these animals consists of a head, torso and legs. The leg is the abdominal, part of the body that looks like a wide sole and serves as an organ of movement.

For molluscs, the mantle and shell are typical. The mantle is a special fold in the cavity of which the respiratory organs (gills or lungs) are located. The shell plays a supporting, motor and protective role, that is, it performs the function of an external skeleton. On the head of the mollusk there is a mouth opening, sensory organs and tentacles for grasping prey. In the throat there is a grater that acts as teeth and serves to scrape off plant food and grind it.

Everywhere in our reservoirs live representatives of the type of mollusks - toothless, pearl barley, pond snail, coil, meadow. Terrestrial molluscs - snail and slug - harm cultivated plants.

V warm seas and the oceans inhabit cephalopods(squid, octopus). These are the most mobile and largest representatives of this type. Some squid reach 18 m in length. They have tentacles on their heads, which represent a heavily modified leg. Cephalopods feed on fish and vertebrates. Squid and octopus meat is eaten.

Type Arthropods. This type stands out among invertebrates for its diversity, number of species and adaptation to life in different conditions... Arthropods live on land, in water, in soil; they are the most abundant animals on our planet.

The body of arthropods is covered with a dense cover of chitin (horny substance), which serves as an external skeleton and performs a protective function. Arthropods are the most highly organized animals among invertebrates. The most typical representatives of the arthropod type are the crustacean, arachnid and insect classes.

Flight fitness is found in many insects. For example, a dragonfly flies very quickly with the help of two pairs of light transparent wings, getting food (mosquitoes, flies) on the fly. The complex eyes of a dragonfly, which occupy almost the entire head, allow it to see well around and quickly change the direction of flight. Adaptation to long-term flight is expressed in bees and some beetles. Along with the wings, they have air sacs located in the abdomen and making flight easier.

The mouth organs of insects are very diverse (gnawing, licking, sucking and stabbing). Their structure depends on the nature of the food. So, insects that feed plant food, have a gnawing mouth apparatus (grasshopper, May beetle), and butterflies feeding on the nectar of flowers have a soft and flexible sucking proboscis.

A characteristic feature of insects is a good development of the nervous system and sense organs. Many insects, such as bees and ants, have complex behaviors.

Representatives of this class are subdivided into insects with complete and incomplete transformation. With incomplete transformation from an egg, a larva appears, similar to an adult. Then the larva molts several times and gradually turns into an adult insect. Such insects include orders of cockroaches, praying mantises, orthoptera (locust, grasshopper), hemiptera (bug) and a number of others.

Insects with complete transformation are distinguished by the fact that all of them in the larval stage do not resemble adult insects and in their development after the larva they go through the pupa stage. These are orders of Lepidoptera (butterfly), beetles (ground beetle), Hymenoptera (bee, wasp), Diptera (fly), etc.

The importance of insects in the life of nature and man is enormous. Some of them pollinate plants (bee, bumblebee, butterfly), which helps them to reproduce. Insects living in the soil contribute to the improvement of its composition and fertility. A huge mass of insects are orderlies in nature (dung beetle, dead eater), since they live off carrion. Insects, in turn, feed on other animals.

At the same time, some insects cause great harm to agriculture and forestry (aphids, locusts, unpaired and ringed silkworms, bark beetles), are pests of animal husbandry (horsefly), carriers of many diseases (fly, mosquito).

Vertebrates. The highest subtype of chordates are vertebrates, including the classes of fish, amphibians, reptiles, birds and mammals. Vertebrates are characterized by an internal skeleton, the basis of which is a strong axial rod - the notochord or spine. Vertebrates have two pairs of limbs - front and back.

All vertebrates have a body consisting of a head, tail, trunk, limbs (two pairs). Internal organs are located along axial skeleton; the circulatory system is closed; the nervous system and the sense organs are very complex and structurally perfect. Vertebrates represent the highest stage in the complication of the structure of animals, characterized by complex mental activity.

Pisces class. These are aquatic vertebrates, the entire organization of which is adapted to an active mobile lifestyle in water. Fish breathe with gills, move (swim) with the help of the tail as parts of the body and fins (locomotion organs), among which the caudal fin plays the main role. The latter acts as a rudder. The scaly cover protects the fish body from damage. The scales are covered with mucus, which makes the fish glide easily in the water. The movement of fish in the water is also facilitated by the shape of the body - elongated, streamlined, compressed from the sides.

Most fish have a swim bladder, an organ associated with swimming. It lightens the overall body weight of the fish in the water, and also helps it to stay at different depths (by contracting and expanding).

Depending on different conditions, fish have adapted to live in different layers of water: in the water column (herring, roach), at the bottom (flounder), in thickets of aquatic plants (pike, perch). Fish live in salty and fresh waters; according to the way of feeding, some of them are predators (pike), others are herbivores (roach), feeding on algae and invertebrates. In this regard, a wide variety of forms is observed in fish.

According to ecological characteristics (in relation to the composition of water and habitat), fish are divided into marine (herring, cod), anadromous (salmon, beluga, sturgeon) and freshwater (crucian carp, pike, carp). Anadromous live in the seas, and for spawning they enter rivers.

Fish reproduce by caviar. The female spawns into the water, the male releases seminal fluid. Fertilization takes place in water. Most fish do not show the instinct of caring for the offspring, and their existence in nature is supported only by a huge amount of spawned eggs (up to 90,000 eggs in pikeperch).

With the onset of cold weather, the bulk of the fish ceases to feed and move, lies for the winter in deep holes, often covered with a thick layer of mucus.

It is impossible to imagine the life of land ponds without fish and Of the World Ocean: after all, they are the most massive and mobile vertebrates. Feeding mainly on aquatic plants, invertebrates, fish themselves become food for many other species of animals. This is how complex food connections are formed, which ensure the normal functioning of aquatic systems.

Fish is the most important human food product. Herring and cod fish are of the greatest commercial value. Many valuable commercial fish live in fresh waters (pike perch, bream, carp, etc.).

Class Amphibians, or Amphibians. Amphibians are an intermediate group of animals between terrestrial and aquatic. These include frog, toad, newt, salamander. Amphibians became the first terrestrial vertebrates, maintaining a close connection with the aquatic environment and the need for a certain atmospheric humidity. This can be explained by insufficient lung development, additional skin respiration, which occurs only in a humid atmosphere. Their thin, delicate skin must be constantly moist, so amphibians have to live in damp places. Reproduction in them is possible only in water, since their eggs are devoid of shells and are not protected by anything from drying out.

Among amphibians there are species that live in water (newt, lake and pond frogs), they have a more primitive organization than terrestrial ones ( grass frog, toad). Aquatic animals are diurnal, and land animals are nocturnal. The skin of amphibians is covered with abundant mucus, in some species (toad, toad) mucus not only moisturizes the skin, but also serves as a protective device against enemies, since it has poisonous properties.

All amphibians feed on animal food, mainly invertebrates (insects, slugs), pests of forestry and agriculture. With the onset of cold weather, they hibernate: frogs hibernate at the bottom of reservoirs, toads - under the roots of trees.

Class Reptiles, or Reptiles. These are the first true terrestrial vertebrates. In terms of morphological features, reptiles are significantly higher than amphibians. In connection with life on land, they have developed a dense horny covering that protects the body from desiccation. Reproduction takes place on land (egg laying and live birth). Respiration is pulmonary. Living on land made their limbs more powerful. The complexly arranged nervous system and perfect sense organs allowed reptiles to adapt much better than amphibians to various conditions of existence (in water, forest, desert).

The most common reptiles are lizard, snake, turtle, crocodile. Their body temperature is unstable, animals are active only in the warm season. For the winter in temperate climates, they hibernate. Reptiles feed mainly on animal food, so many have well-developed teeth. The lizard destroys a huge number of harmful insects and molluscs.

Bird class. Birds belong to a specialized branch of higher vertebrates that have adapted to flight. Most characteristic feature external structure birds are easy to spot - this is a feather cover. Feathers give the bird a streamlined shape, promote thermoregulation, retain heat, reduce water loss through the skin, and protect the skin from damage. The forelimbs have turned into wings - the organs of flight. Since birds fly through the air, they have developed special adaptations: a light and strong skeleton, a lightweight beak devoid of teeth, and a movable neck. Flying helps birds to find food faster, escape from enemies, choose places for rest and breeding.

Birds have a constant high body temperature (about 40 C), which is associated with a significant metabolic rate. The progressive traits of the organization of birds are expressed in more perfect reproduction (incubation of eggs and feeding of chicks). The high level of development of the nervous system allows birds to better adapt to the environment.

The way of life of birds depends on climatic conditions, the nature of food and methods of obtaining it, and the characteristics of nesting sites. The following ecological groups are distinguished: running birds (ostrich, bustard), aquatic inhabitants (penguin), waterfowl (goose, duck), marsh (heron, stork), daytime predators (eagle, hawk), nocturnal predators (owl), woodpecker ), ground (chicken), small birds a detachment of passerines (crow, sparrow, titmouse, swallow), flying (all birds, except for the ostrich and penguin).

By the nature of the diet, birds are herbivorous (bullfinch, wood grouse), insectivorous (swallow, tit) and carnivorous (eagle).

According to the type of hatching of chicks, birds are divided into brood (chicken, anseriformes, etc.) and chicks (passerines, woodpeckers, etc.).

Birds have complex instincts - building nests, singing, caring for offspring, flying. All this is due to the greater development of their brain than that of reptiles.

One of the most interesting aspects of bird behavior is annual migrations (flights). Flights allow birds to avoid unfavorable seasonal conditions (cold and lack of food). Most of the birds in the forest zone are migratory (swallow, cuckoo, warbler, sandpiper, heron, etc.). Birds that live within a small nesting area are sedentary, such as the sparrow and jackdaw. Wandering birds wander within the boundaries of the nesting area of ​​the species (titmouse, woodpecker, bullfinch, waxwing).

Birds are of great importance in human life. They destroy a huge number of harmful insects, rodents, provide people with an invaluable service in protecting forests, fields and gardens from various pests. Poultry provides valuable food, feathers and down.

Birds adorn nature with their singing, liveliness of behavior, color of plumage. Songbirds are a huge living wealth of our forests. They need our protection and care. We need to work hard and skillfully if we want to constantly see and hear birds in gardens, parks, forests (hanging nesting sites, feeding).

Class Mammals, or Beasts. Mammals are the most highly organized animals on our planet. They are very numerous, widespread throughout the globe (absent only in Antarctica), adapted to life on land (most), in water, air, soil.

The main progressive features of this class include, first of all, the high development of the central nervous system, especially the cerebral cortex, which provides complex and perfect adaptive responses to environmental conditions. In addition, the progressive traits of animals of this class also include viviparity and the feeding of young with milk, which gives them the opportunity to reproduce in different conditions. Mammals have a constant body temperature.

Mammals have morphological signs: the body is covered with hair (hair), which is very important for thermoregulation; the skin is rich in glands (sweat, sebaceous, odorous, milky); the teeth are differentiated into incisors, canines and molars. Due to the latter circumstance, a variety of feeds can be used.

The appearance of these animals is diverse, it is directly dependent on environmental conditions and lifestyle. Terrestrial four-legged animals are most often found. They have well-developed limbs, a body raised high above the ground, and a well-developed cervical region.

Many of the land animals live in the forest: the squirrel leads an arboreal lifestyle and feeds mainly on the seeds of conifers; deer, elk, bear, white hare eat a variety of plant foods. Marten, sable move well in trees, feed on berries, nuts, small animals. Beasts of prey- fox, weasel, ermine, ferret.

Underground animals that have adapted to live in the soil (diggers) are moles. They have a cylindrical body, short legs with strong long claws. Moles feed on earthworms and insect larvae.

Inhabitants of open spaces are ungulates (deer, antelope), rodents (gopher, hamster, hare), predatory (wolf, tiger). The ungulates have adapted to running quickly on the ground, to coarse plant foods. Gnawing mammals have strongly developed incisors, no canines. The hare eats plant food (bark of aspens, apple trees), moves in leaps, hind limbs are strongly developed. Small rodents (marmot, shrew, vole) dig holes for themselves and use them to store supplies, breed offspring, and protect themselves from enemies. Carnivores, feeding on animal food, run quickly, chase and hunt down their prey.

Aquatic beasts adapted to the aquatic lifestyle. Among them there are those who cannot live without water, but at the same time live on land, since food is obtained both in water and on land (beaver, muskrat). Pinnipeds are better adapted to aquatic life. The seal lives mainly in the water, gets food there, but multiplies on land. Cetaceans are most adapted to life in water. The body of these animals has a fish-like shape, hairline remained on a few parts of the body, the front limbs turned into flippers, the hind limbs are gone. The whale, like other mammals, breathes with its lungs, rising to the surface of the water. The whale gives birth to cubs and feeds them with milk in water.

Many animals of the temperate zone prepare for the cold period of the year - winter: they feed hard, shed (change their hairline to winter, longer and more luxuriant, with undercoat), which makes it easier for them to endure low winter temperatures. Some mammals hibernate in winter, for example, bear, hamster, badger, ground squirrel; others store food for the winter (squirrel, beaver). Many animals are active in winter as well, as they can feed themselves (wolf, fox, elk, hare).

The importance of mammals in human life is very great and diverse. Many domestic animals belong to the class of mammals. Their role in the national economy is enormous: they provide people with the necessary food products and raw materials for industry. A number of mammals have become the subject of hunting.

Among mammals there are serious pests of agriculture and carriers of infectious diseases (rodent pests, etc.) - they have to be fought with.

Pets. The overwhelming majority of these animals are representatives of the mammalian class. These animals are called pets because they are tamed by a person, live under his care, breed under his control, and are bred for various economic purposes. These animals have changed a lot and cannot live on their own in natural conditions... Domestic animals have ecological plasticity: they can quickly adapt to changing conditions under the influence of artificial selection and education.

Domestic mammals include large cattle, sheep, goat, camel, pig, etc. Cattle (cow, yak, buffalo) are used as a worker, dairy and meat. A huge number of various breeds of sheep (sheepskin-fur coat, fine-fleece, karakul, fat tail) have been bred. Goats are bred for meat, milk, wool. The camel is an indispensable draft and mount for desert areas, and it also provides wool, milk and meat.

Great importance for humans have a horse, donkey, dog, rabbit and many other pets.

Pets also include birds - chicken, goose, duck, turkey. They are bred for meat, eggs, feathers and down.

Questions and tasks.1. What are the main differences between animals and plants? 2. What invertebrates in your region are often found? 3. Prove that vertebrates are the highest stage in the development of the animal world. 4. How are fish adapted to life in the water? 5. What is the reason for the migration of birds? 6. What is the significance of birds in nature and human life? 7. Describe the main ecological groups of mammals. 8. How are domestic animals different from wild animals?