All plants growing under water are called algae, but this is incorrect. Algae differ in their structure from most plants.

Features of the structure of algae

Algae are primitive plants. Although their body may look like an ordinary plant in appearance, it is not divided into organs and is called a thallus, or thallus.

Algae include:

• unicellular;
• colonial;
• multicellular.

The body of unicellular algae is represented by a single cell, often with a flagellum for locomotion. They live both in the ocean and in small puddles and ditches.

In cells, a green chromatophore is especially noticeable. It has a varied shape and is similar to plant chloroplasts.

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Volvox is an example of colonial algae.

Rice. 1. Volvox under a microscope.

With asexual reproduction in Volvox, new generations remain associated with the mother, and a colony is formed.

The thalli of multicellular algae have a different shape.

Habitats:

• in fresh waters;
• in salty waters;
• in the soil;
• on the surface of trees, buildings, stones;
• on snow and ice.

Some diatoms and green algae live in hot springs with water temperatures up to +51 degrees.

reproduction

The reproduction of algae occurs in a variety of ways, but it belongs to three types:

• vegetative;
• asexual;
• sexual.

Vegetative is observed in filamentous algae. Their thallus is torn apart and a new organism is formed from each.

Asexual reproduction occurs with the help of spores. The mother cell is divided into several parts. Each part becomes a controversy. Subsequently, a new alga grows from the spore.

Rice. 2. Asexual reproduction of chlamydomonas.

During sexual reproduction, the fusion of gametes (sex cells) occurs in special mother cells. As a result, a zygote is formed - the first cell of a new organism.

Table "Diversity of algae"

In addition to the main groups of algae indicated in the table, there are also:

• diatoms;
• yellow-green;
• golden.

Diatoms are common in the seas and fresh waters. Their feature is the presence of a shell of silica. When shells are deposited at the bottom of reservoirs, a rock diatomite.

Rice. 3. Shells of diatoms under a microscope.

The value of algae

In nature:

• algae saturate water bodies and the atmosphere with oxygen;
• aquatic animals feed on them;
• form silt and chalk rocks;
• cause with strong reproduction "blooming of water".

In human life, algae are used in various ways:

• as feed or food supplement for animals;
• for human nutrition;
• silt is used as a fertilizer and in medicine;
• in the biochemical and confectionery industry to obtain proteins, alcohols, iodine, bromine, vitamins, agar-agar.

Many types of algae are edible. The most famous are brown kelp (which is called sea kale) and fucus, as well as green ulva (sea lettuce).

Many scientists argue that algae factories will become widespread in the future. These factories will grow edible algae and produce various products from them.

Examples of the use of algae for animal feed have been known for a long time. In many seaside areas of the world, farmers added algae to livestock feed. Nowadays, seaweed briquettes are sold in the USA for this purpose.

What have we learned?

6th grade student preparing a report or homework in biology, must know the main groups of algae and their significance. Algae are very widely distributed. The main role of algae on the planet is the synthesis organic matter and oxygenation of the ocean and atmosphere. According to scientists, their nutritional and industrial importance for humans will continue to grow.

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Biology lesson plan.

Topic: Algae, their diversity and importance in nature.

Class 6 (FGOS).

UMK N.I. Ponomarev.

Textbook: Biology: Grade 6: a textbook for students of educational institutions / I.N. Ponomareva, O.A. Kornilova, V.S. Kuchmenko; ed. prof. I.N.Ponomareva.- M.: Ventana-Count

The purpose of the lesson: form an idea of ​​\u200b\u200balgae as lower plants.

Tasks:

1. To get acquainted with the features of the habitat, structure and activity of algae;

2. Study the general signs of algae;

3. Determine the signs of unicellular and multicellular algae;

4. Continue the formation of skills to work with various sources of information: textbook, electronic educational program 1C: School, etc. ICT (audio content, video content, multimedia).

5. Raising environmental awareness and respect for the habitat of algae.

Equipment: interactive equipment "Promethean", presentation files, PC, magnetic board with magnets, herbarium material "algae", clean sheets A-4(to create a scheme, reference signs in the work of groups),

Using UUD components:

Ability to hear, listen, plan and work together in a coordinated manner;

Interact with each other, support each other, be able to lead a discussion;

Express your thoughts correctly

Collaborate effectively with both the teacher and peers;

Willingness to carry out directed search, processing and use of information in work;

Ability to identify the essential;

Ability to recognize the cognitive task;

Understand information presented in pictorial, schematic form,

Use sign-symbolic means;

Ability to solve problems and problems.

Skills in the formation of arbitrariness of behavior in individual and joint work;

Emotional evaluation of what is happening and what has been studied;

During the classes.

1. Checking students' knowledge.

What is the importance of systematics in the study of wildlife.

What are plant species called?

What taxa are distinguished in the classification of plants.

Natural scientist who introduced binary species names.

Establish correspondences between taxonomic units and proposed group names. What group name is superfluous, why.

What plants are classified as higher.

Intermediate result:determination of the quality of assimilation of the studied material "Systematics of plants, its significance for botany."

1. The study of the material.

Intermediate result:defining the purpose of the lesson. Understanding that there are similarities and differences between the plants presented. Understanding the need to study the structural features of algae.

Intermediate result:assimilation general characteristics department "Algae". A) Algae are lower plants, because the body is represented by a thallus, or thallus. It does not contain organs and tissues. B) Chlorophyll is found in chromatophores. C) Algae are autotrophic organisms. Assimilation of the differences of algae. A) There are unicellular and multicellular algae. B) The body shapes of algae are diverse. C) Chlamydomonas has flagella, an eye, a contractile vacuole - structures characteristic of a free-living organism.

Intermediate result:knowledge of the structural features of unicellular algae. Assimilation of body parts, functions of body structures. Memorizing new concepts and consolidating knowledge of the structure of a plant cell and the structures of free-living organisms.

Intermediate result:the skills of working in a group and interacting with group members and the teacher were worked out. A joint analysis of the content of the material was carried out. The skills and abilities of using a diagram, table, reference signs, etc. have been worked out. when solving a learning problem. Acquired knowledge of the characteristics of algae reproduction, the diversity of algae, the importance of algae.

Scheme number 1. "Reproduction of algae"

Scheme No. 2. "Diversity of algae"

Algae names.

Depth of habitat in water bodies.

Scheme number 3. "The value of algae"

Participate in the formation of oxygen, the saturation of the aquatic environment and the atmosphere with oxygen;

Conducts a small survey on the studied blocks. Summarizes the work of the groups. Summarizes the material studied. After watching the video, he suggests thinking about the role of algae in the existence of living beings on the planet. Raises a problem for thought.

The role of man in the conservation of biological diversity.

The role of man in the conservation of algal habitats.

Ways to solve the problem of water pollution.

Effective and safe for aquatic life methods of cleaning water bodies.

They carefully watch the video, evaluate the information in the video. They say that they additionally learned from the film.

Thinking about the problem. Answer questions and offer solutions to problems.

Intermediate result:reflections on the issue of algae conservation and the protection of algae habitats. Emotional assessment and attitude to environmental problems. Ability to offer own conclusions, own ways of solving the problem. Consolidation of the studied material.

1. Summarizing.

Use the interactive possibilities of ICT;

Prepare equipment for the lesson, interactive manuals;

Maintain the time frame of each learning component of the lesson;

Provide metered assistance to students in their work, motivate them to study the material, create a situation of success for each student;

Involve low-performing students in the survey and work, offering them a form of work that is successful for completion (for example, working with an interactive manual with ready-made answers);

Use a variety of different forms perception of the material;

Use multivariate forms of work,

Mandatory inclusion of a textbook in the work, without overloading the lesson with a presentation, slides.

In preparation for the lesson, materials from the Internet resource were used

Variety of algae

Algae are a very ancient group of organisms on Earth. During the existence of algae, many forms of structure, features in reproduction and settlement on our planet have arisen. In total, there are about 30 thousand species of algae.

According to the structural features and color of the thallus, green, red, golden, brown, diatoms and other algae are distinguished.

Green algae. Among them are unicellular and multicellular. They include chlorella, ulva, spirogyra, chlamydomonas, ulotrix .

in the genus chlamydomonas- more than 500 species. Almost all of them are inhabitants of small, well-heated and heavily polluted water bodies. Along with the autotrophic way of feeding, all representatives of chlamydomonas absorb organic substances dissolved in water with their entire surface, helping to purify polluted waters. This ability of these algae allows them to be used in sewage treatment plants.

In ponds, lakes, backwaters of rivers, you can often see slippery green mud floating on the surface of the water. If we look at mud under a microscope, we can see that it is formed by a large accumulation of the thinnest green threads. It is a multicellular filamentous algae spirogyra. In slightly polluted waters of sea coasts, such as the Black Sea, bright green algae grows ulva, whose flat wavy thallus is up to 20 cm wide. Many peoples use ulva as food under the name "sea salad".

Some colonial forms also belong to the department of green algae -Volvox, Eudorina, Pandorina . Some of their cells are built according to the type of chlamydomonas, but during reproduction, the cells do not diverge, but grow together with their membranes or remain connected by a common mucus. They are widespread in stagnant water bodies, where they also cause water blooms. Volvox is the most highly organized. Some specialization of cells is already observed in its colony.

If for green algae the usual environment is fresh water, then the vast majority of brown and red ones form real forests and thickets in salt water. They also live in the tidal zone, where they remain without water for a long time and survive the impacts of the waves, and at a fairly significant depth, where the sun's rays almost do not penetrate.

Interactive lesson-simulator "Green algae department".

(Go through all the pages of the lesson and complete all the tasks)

brown algae are large, multicellular plants. They got their name because of the color of the thallus. In addition to chlorophyll, the cells of these algae also contain other pigments.

For the most part, brown algae grow attached to solid ground or other algae, which is different from other algae. To attach to the ground, they are served by special outgrowths of the thallus - rhizoids , which are long root-like growths. Brown algae are annual and perennial. For example, at kelp rhizoids and stem are perennial, and the long ribbon-like (lamellar) part of the thallus is annual. It grows back every year from the stem.

Brown algae can reproduce vegetatively. With the help of biflagellate spores - asexually. Individuals grow from spores, on which germ cells - gametes are formed. After fertilization, the zygote gives rise to algae, on which spores will form. Consequently, for brown algae, the alternation of two generations is characteristic - sexual and asexual.

Brown algae is one of the main sources of organic matter in the coastal zone of oceans and seas.

In their thickets, similar to an underwater forest, numerous animals take shelter, find food and oxygen. Many brown algae are used as food for humans, used in industry, used for livestock feed and as fertilizer.

red algae, or scarlet. A set of different pigments in combination with chlorophyll determines the color of crimson - from bright red to bluish-green and yellow. This is a very ancient group of algae. Therefore, they have some differences from other, "younger" departments. In length, red algae are inferior to brown algae (no more than 2 m). The combination of different pigments of crimson gives them a color from bright red to bluish and yellow. Reproduction of red algae (asexual and sexual) is a more complex and diverse process than that of other departments. Bagryanka surprisingly adapted to life in the coastal zone. Here they are washed not only with sea water, but also with fresh water, freeze in winter, and dry out at low tide. But the tide comes and they come alive. It is the scarlet that can survive on the rocks, where the surf is constantly acting. The crimson thallus has been growing for many years and has a variety of forms: lamellar, bushy, filiform. The most famous seaweedpurple. It reproduces only sexually.

(Complete all the tasks of the lesson)

The value of algae great in nature. They absorb the sun's rays, penetrating to a considerable depth, and form organic matter. At the same time, oxygen is released into the water, and carbon dioxide is absorbed from the water.

Brown algae are one of the main sources of organic matter in the coastal zone. Their biomass can reach tens of kilograms per square meter. Thickets of brown algae serve as a shelter, breeding and feeding place for coastal animals. They also create conditions for the settlement of other, smaller algae. Charles Darwin wrote aboutmacrocystis piriformis , which occupies the same position in south seas, as kelp in the northern: “I can only compare these huge underwater forests with the terrestrial forests of tropical regions. And yet, if a forest were to be destroyed in some country, I don’t think that at least approximately the same number of animal species would die as with the destruction of this algae.

Man widely uses algae. In medicine - earlier only to obtain iodine, and now - in the manufacture of blood substitutes, drugs that help remove radioactive substances from the body, in surgery. residents of Japan and Far East have been used for food for a long time. kelp. Today, however, these algae have become even more important in industry.

From algae, chemicals are obtained that are necessary in the manufacture of tablets, diabetic products; in the production of plastics, synthetic fibers, resins, paints, paper, explosives. Adding a small amount of them improves the quality of long-term products (canned food, ice cream, juices). Brown algae are used in animal husbandry and crop production. Brown algae contain iodine and other trace elements, so feed flour is prepared from them - an additive in feed for farm animals. Due to this, the loss of livestock is reduced, productivity is increased, and the content of iodine in milk and eggs increases. purple can be used for food. In Japan, it is specially bred.

Red algae go to get agar-agar. It is added to bread so that it does not become stale, marshmallow, jelly, and marmalade are made from it. Agar-agar is the best medium for growing microorganisms. Capsules and tablets with antibiotics and vitamins are made from agar. Iodine is obtained from red algae. From crimson, together with other algae, flour is produced, which is used to feed livestock and as fertilizer. Red algae grow in all the seas of the World Ocean, but their role is especially significant in the tropics, where they outnumber brown and green algae. In the life of the sea, they play a role similar to brown and green.

In addition to multicellular, rather large algae, a huge amount of microscopic algae lives in the World Ocean. Together with spores of multicellular algae, they form phytoplankton (from Greek. phyton- plant and plankton- wandering). It inhabits the surface, well-lit layers of water. This is the main producer of organic substances, the initial link of most food chains in the reservoir.

In fresh waters, the place of red algae and brown spores in phytoplankton is occupied by green algae.

Algae are lower plants that have a unicellular and multicellular structure. They are called inferior because their body is not differentiated into absorbing and photosynthesizing parts, as is observed in all other representatives of the plant kingdom. Algae is one of the oldest representatives of organisms, a giant source of oxygen, organic matter and energy for the entire living world. They contain many valuable substances used in industry, agriculture, medicine and human nutrition. Algae are a great asset to our planet.

Algae are most often referred to as plants that grow in water, but the group of living organisms is much larger and includes single-celled life forms, some of which are less than microns in size. They can live:

• in the water column, without being attached to any object or inhabitant of the underwater world;
• at the seabed, attaching to it and other algae with a thallus;
• in the upper layers of the soil;
• on trees, hedges, house walls, etc.

Algae types

Algae are distinguished by the number of cells:

• unicellular;
• multicellular (mainly filamentous);
• colonial;
• non-cellular.

There is also a difference in the structure of cells and the pigment composition of algae. In this regard, there are:

• green(with a green tone and slight splashes of yellow);
• blue-green(with pigments of green, blue, red and yellow shades);
• brown(with green and brown pigments);
• red(with pigments of various shades of red);
• yellow-green(with coloring of corresponding tones, as well as two flagella of different structure and length);
• golden(with pigments that form a golden color, and cells that do not have a shell or are enclosed in a dense shell);
• diatoms(with a strong shell, consisting of two halves, and a brownish color);
• pyrrhophytic(brownish-yellow shade with bare or shell-covered cells);
• as well as euglena algae(unicellular, naked, with one or two flagella).

Algae reproduce in several ways:

• vegetative(by simple cell division of the organism's body);
• sexual(fusion of germ cells of a plant with the formation of a zygote);
• asexual(zoospores).

Depending on the type of algae and how favorable the environmental conditions are, the number of generations in just a few years can exceed 1000.

The impact of algae on the environment

All types of algae, due to the presence of chlorophyll in the cells, form oxygen. Its share of the total volume produced by the plants of the planet Earth is 30 - 50%. By producing oxygen, algae absorb carbon dioxide, the percentage of which is quite high in the atmosphere today.

Algae also act as a food source for many other living beings. They feed on molluscs, crustaceans, different kinds fish. Their high adaptability to harsh conditions provides high-quality nutrient medium plants and animals high in the mountains, in polar regions, etc.

If there is too much algae in the reservoirs, the water begins to bloom. A number of them, for example, blue-green algae, actively release a toxic substance during this period. Its concentration is especially high at the surface of the water. Gradually, this leads to the death of aquatic inhabitants and a significant deterioration in water quality, up to waterlogging.

The value of algae for humans

Algae benefit not only the flora and fauna. Mankind also actively uses them. The vital activity of organisms in the past has become for the modern generation a source of minerals, in the list of which it is worth noting oil shale and limestone.

Algae that are edible to humans are eaten. They enrich the body with useful trace elements and are a source of iodine.

A number of algae are actively used to purify water in artificial closed systems, such as aquariums.

isolated from algae useful material, which are used as dietary supplements, are included in vitamin and mineral complexes and are actively used in cooking.