Summary of the lesson "Organisms in the oceans. The impact of organisms on the earth's shells"

People have long been accustomed to the existence of a diverse animal and flora on the land. What do we know about life in the ocean? How diverse is it? Who, besides commercial fish, can be found in its waters? Let's look for answers to these questions together.

Amazing Diversity

Life in the ocean is amazing and diverse. Scientists are sure that life began its development in the waters of the oceans. This can explain the fact that more than 150 thousand different species of representatives of the animal and plant world live here. If you try to calculate the total weight of all life forms of ocean waters, then the figure will turn out to be huge - in fact, it is 60 billion tons. The ocean as a habitat was suitable for all types of organic world. Huge mammals are also found here. Of the huge variety of wildlife in the waters of the ocean, only spiders, centipedes and amphibians did not take root.

Differences between the water and air environment

Argue with what is airy and differ in physical properties, hopelessly. AT aquatic environment temperatures are distributed differently, water pressure increases in accordance with depth. Also the presence sunlight observed only in the upper layers. These features of life in the ocean affect the existence and development of all life.

Thus, due to the fact that water is able to support organisms in a certain position, they do not need to form particularly strong skeletons or roots. Therefore, life in the ocean is represented by the largest mammal in nature, which is called the blue whale. This animal is 25 times heavier than the largest inhabitant of land - an elephant.

Well, since ocean algae do not have to resist air element, then they do not need to grow a powerful root system, but at the same time they can stretch for several tens of meters.

What is benthos?

This incomprehensible word defines the totality of living creatures that live on and in ocean soil. There are two varieties of life on the ocean floor: zoobenthos and phytobenthos. Representatives of the zoobenthos, that is, the animal world, are much larger, and as they approach the shores of the continents and islands, their number increases in shallow water.

Zoobenthos is represented by crustaceans, mollusks, large and small fish. Phytobenthos includes various bacteria and algae.

What is plankton?

Well, what kind of life in the ocean without special ones that are not tied to the bottom, but are not able to actively move. In fact, all the movement of plankton occurs due to currents. The upper layers of water, where sunlight hits, inhabits phytoplankton. It consists of various types of algae. But zooplankton lives in the entire water column.

Most of the animal plankton are crustaceans and protozoa. These are various ciliates, radiolarians and other representatives. In addition, there are intestinal organisms: siphonophores, jellyfish, ctenophores and small pteropods.

Thanks to the huge amount of plankton, fish and aquatic animals are always provided with plentiful food.

What is a nekton?

The term "nekton" is not very common, but it refers to life forms that are well known to us. Nekton - organisms that can actively move in the water. These are turtles, and pinnipeds, and cetaceans. Nekton also includes all types of fish, squid, penguins and water snakes.

Division into zones

Life in the ocean is interesting because it creates different conditions for the inhabitants of different depths. So, shallow water off the coast is called the littoral zone. Here waves of water, ebbs and flows are common phenomena. This forced living organisms to adapt to the daily change of being in water and in the air. In addition, these organisms are constantly affected by temperature fluctuations, changes in environmental salinity and surf. To survive in these conditions, molluscs are firmly fixed on the rocks, crabs are held by tenacious claws, and fish have acquired special suction cups. And the shrimp have learned to dig into the ground.

The next zone is bathyal. It starts at a depth of 200 m and ends at a depth of 2000 m. The bathyal zone is located within the continental slopes. The flora of this zone is very poor, because Sun rays do not go to that depth. But there are many fish here.

Further, the habitat zone is called abyssal. It is located at depths of more than two kilometers. Here the water is slow moving and the temperature is consistently low. The salinity of the ocean at this depth can reach 34.7%, there is no light at all. Vegetation in this zone is represented by species of bacteria and algae. BUT animal world ocean depths is very unusual. The bodies of animals are delicate and fragile. Many species have acquired long appendages in order to lean on viscous soil and be able to move around. Some living organisms have huge eyes, while others are completely absent. Many species are flat, some organisms are able to glow.

The deep-sea flora and fauna have not yet been fully studied, since descent to great depths is difficult not only for humans, but also for research instruments. Research with the help of self-propelled submersibles has become widespread. But the life of the littoral and bathyal zones is being actively studied.

The riches of the World Ocean provide humanity with a huge food source. And most importantly, this food source is saturated with vitamins and easily digestible protein. Representatives of not only the animal, but also the plant world are suitable for food. The main thing is that a person does not consider this source inexhaustible and learns to treat it carefully and economically.

Zadovskaya A.A. geography teacher

Iqualification category

MBOU Christmas secondary school

Laishevsky municipal district of the Republic of Tatarstan

Geography lesson “Features of life in the ocean. The spread of life in the ocean, Grade 5

Type of lesson - study new material.

Lesson Objectives - to form an idea about the features and distribution of life in the ocean.

Tasks:

to find out the features of the spread of life in the ocean, the factors influencing the features of the spread of the org.world, to introduce new concepts;

improvement of work with sources of geo-information, development of speech, memory of students;

continue the formation of a worldview, a positive attitude to the subject, the ability to behave in the classroom, careful attitude to educational supplies

Concepts: plankton, nekton, benthos, their features, the diversity of marine organisms, factors affecting the spread of life in the ocean, the relationship between depth, climate and distance from the coast and the diversity and richness of the organic world, ways of adapting marine plants and animals to aquatic conditions of existence.

Equipment: a map of the hemispheres or a map of the World Ocean, encyclopedias, TV, videofilm "Life in the Ocean", tables, drawings, student reports.

During the classes.

"Look at the ocean, professor, isn't that creature?.."

From the conversation between Captain Nemo and Professor Aronax.

I . Teacher: Today in the lesson we will learn a lot of interesting things about the organisms that inhabit the oceans. What groups are divided into, what living conditions, and the distribution of organisms exist in the oceans, on what it depends.

The ocean is full of life and mysteries that amaze the imagination. Many of them are nothave been disclosed so far. Great contribution to the study of life in the oceansContributed by Thor Heyerdahl and Jacques Yves Cousteau.Let's write the topic of the lesson in a notebook.

II . Updating students' knowledge:

What kingdoms of living organisms exist on Earth?

What is the biosphere? What are the boundaries of the biosphere(upper - the level of the ozone layer, lower - Earth's crust about 5 km);

How are living things different from non-living things?

Name the conditions for the existence of organisms;

What is the ozone layer? At what height is it?

III . Opening talk: "On the Diversity of Marine Organisms".

The oceans are inhabited by many animals, plants, bacteria. Unlike land, where plants predominate among organisms, the ocean is an environment dominated by animals. (See Fig. 160, slide). About 160,000 animal species and 10,000 plant species are now known to live in the ocean.

The plants are dominated by algae. They are very diverse - from single-celled tiny organisms to giants tens of meters long. (See fig. 161).(Word to the student).

Marine animals are more diverse (Fig. 162). Their sizes range from tiny unicellular to whales weighing 200 tons (or 50 elephants!).(Word to the student).

Teacher: "Features of life in the ocean."

Water is a special environment. Up to a depth of 200 meters, many small organisms live in suspension. They seem to float on water. Hence the name of organisms -plankton (from Greek wandering) . There are 20 times more plankton in the seas and oceans than all other organisms combined (Fig. 163). It is the main food of fish and whales. Areas rich in plankton are also rich in fish.

Nonplanktonic animals move independently. They swim quickly, overcoming obstacles. To do this, they have special devices: a streamlined body shape, flippers, fins. They inhabit the entire water column from the surface to the bottom.

Special animals inhabit the bottom of the ocean. Some of them never separate from it (corals, anemones, sea lilies), others swim in the bottom waters (flounder, rays). There are also creatures that burrow into the ground (worms, some mollusks, crustaceans).

-

Marine organism groups

animal representatives andflora

1.surface water

1. plankton (gr. wandering) - passively moving (with currents) algae and animals

1. crustaceans, jellyfish, krill, diatoms and plankton seaweed.

2. the entire water column

2. nekton (Greek floating) - actively moving organisms

2. fish, cetaceans, mammals, molluscs octopus, squid; turtles

3. bottom of the ocean

3. benthos (Greek depth) - organisms that live on the bottom

3. brown and red algae, crustaceans, sea ​​stars, molluscs, sea anemones fish, sea firs

Teacher: There are three areas of life and three groups of marine organisms in the ocean.by way of life:

- water surface (inhabitsplankton - from the Greek. wandering - passivemoving (by currents) algae and animals(Students enter the data in the table). Most organisms that form plankton are verysmall, many visible only under a microscope. Plankton is the main foodmost of the inhabitants of the ocean, including such as baleen whales, do nottalking about fish.

Teacher: - And now attention! Let's listen to the guys, they will read us excerpts from the novel “20,000 Leagues Under the Sea. Captain Nemo". - What did Captain Nemo and his passengers see?

1 The student reads a passage from the novel: « In the first minutes of diving when the sun's rays gilded the water, life seethed overboard. We could observe many living organisms: from the smallest algae togiant jellyfish. However, passing through various water layers, it is impossible not to notice that they are unevenly populated. The most populated depth is up to 50 meters."

- water column ( nekton, which in Greek meansfloating. These organisms actively move in the ocean and do not depend onsea ​​currents and winds. This group of organisms is more diverse(students complete the table).

2 Student: This is how Professor Aranaks, a member of the expedition, described his impressions Captain Nemo. : “The fish frolicked, splashed, competing with the beauty of colors, the brilliance of scales and briskness. I noticed green wrasse, red mullet marked with a double black stripe, goby white, with purple spots on the back and a rounded tail, Japanese mackerel, wonderful mackerel with a silver head and blue body, brilliant lapis lazuli, one name of which replaces all descriptions, sparid ribbed, with a variety of fins, blue and yellow, striped sparid, with a black band on the tail, moray eel, genus serpentine eel, with small lively eyes and a wide snarled teeth with your mouth, you can’t list everything ... "

Teacher: -What kind external signs can be noted in fish - inhabitants little depth? What other inhabitants of the water column, besides fish, can be see? Students name representatives and write them down in a table.

- Ocean floor ( benthos from Greek - depth). The depths of the oceans are sparsely populated, but not lifeless, although at great depths there is not even algae. Practicallyin complete darkness, under great pressure, in cold water they swimamazing looking fish. They feed on the remains of organisms "falling" from the upper layers of the water, or eat each other.

3 Student reads : "Sinking, we passed mark 200 meters, the ocean depths changed their color from turquoise to dark blue, the sun's rays almost do not penetrate to such a depth.Our satellites began to disappear - flocks marine fish. We were going down deeper and deeper. And now, at a depth of about 500 m, the last ray of light died out. It was pitch dark... Captain Nemo ordered thesearchlights, and we were surprised to find that there is life here too. Looking closely, we noticed some features of deep-sea creatures: predatory fish had huge mouths,luminous from within, almost all creatures are devoid of color, and many poorly developed eyes.

Teacher: - Why are they like that? What features appearance you drew Attention? Students write down answers in a table.

Teacher: "On the distribution of organisms depending on the depth." When researching sea ​​depths and now organisms are still being found,unknown to science. Life in the ocean is all pervasive. It also exists at the bottom of the Mariana Trench, at a depth of 11 thousand meters, and even where a newEarth's crust.

Living conditions in the ocean from the poles to the equator, from the surface tomaximum depths are very different. What influences the distributionorganisms in the vast waters of the ocean?

Teacher: What do you guys think, what is the most important condition the existence of organisms in the ocean?

Light - the first condition for the existence of green algae in the water,that other organisms feed on. There is less light in water than in air,illumination decreases with depth. Therefore, the upper 50-meters of water. The amount of sunlight decreases with depth. The upper layer of water up to a depth of 100 m is well lit. Almost all plants and all plankton are found in this layer. Down to a depth of 1000 m extends the middle layer of water with twilight illumination. Even deeper - to the very bottom - is the lower layer, which does not receive light at all. There are no plants in it, here is the kingdom of animals and bacteria. Due to complete darkness, animals have developed special adaptations -luminous organs. They are used to attract prey, disguise or mislead the victim or hunter.

Students write in their notebooks:

The distribution of life in the ocean depends on the following conditions:

1. . light

Teacher: What do you guys think, what other conditions affect living organisms in the ocean?

2. availability of nutrients;

3. water temperature;

4. salinity and density of water;

5. amount of dissolved oxygen;

6. currents;

8. water pressure. (the greater the depth, the higher the pressure. In deep-sea animals, the water pressure is balanced by the pressure of the fluid in the body. Life in water layers with different pressures is often reflected in the shape of the body of fish (Fig. 164)

Teacher: We will enter all subsequent data in the table:

Conditions for the existence of living organisms

Examples of living organisms

Distribution of organisms depending on depth

The distribution of organisms depending on the climate:

climate

Arctic and Antarctic belt

Temperate zone

tropical belt

equatorial belt

The distribution of organisms depending on the distance from the coast.

Teacher: "On the distribution of organisms depending on the climate."

Due to climate change from the equator to the poles, the properties of water change, and, consequently, the features of the organic world.

1. In the Arctic and Antarctic Poles life is very poor. There are few species of living organisms, as well as individuals themselves. Plankton develops only in the short summer period and only in places freed from ice. Fish and the walruses and seals that feed on them.

2. In temperate zones t all year above 0 0 C. the abundance of oxygen dissolved in water leads to the rapid development of life. In temperate zones, the diversity of organisms is not very large, but there are many individuals of each species. Temperate latitudes are rich in fish, and it is actively fished here (herring, hake, cod, saury, salmon).

3. In tropical zones high all year roundtwater and high salinity. There is little oxygen and nutrients in the water, less plankton, and therefore less fish. However, in hot zones there is a huge variety of heat-loving fish and bottom organisms (corals, mollusks, echinoderms, crustaceans).

4. In the equatorial belt twater all year high. Rapid development is observed near the mouths major rivers carrying nutrients into the ocean. There are many coral structures at the bottom. In the equatorial waters are catching sea ​​turtles, shellfish, tuna, sardine, mackerel.

Students fill in the table in their notebooks:

Teacher: "On the distribution of organisms depending on the remoteness of the coast."

The most favorable conditions for both plants and animals are found in shallow water areas. These are the shelves of the seas and oceans. They make up 9% of the world's oceans. There is a lot of light, heat, nutrients, oxygen. Toward the open ocean, the saturation of life decreases hundreds of times.

A rich world of benthic animals has been found in areas of the ocean floor, where there are outlets of hot groundwater and gases. Large molluscs live here, vestimentifera - outlandish creatures that look like worms (up to 1 m in length)

- What do you think these living organisms eat?

These and other animals feed on special bacteria that are not created in the process of photosynthesis, but through chemical reactions.

IV . Teacher: Now the guys will introduce you to the most amazing inhabitants World Ocean. (Performances are accompanied by a slide show). Computer presentation.

1. The most northern mammals - Polar bear.

Although the bear does not live permanently in the water, its life is inseparable from the ocean. Polar bear - inhabitant Far North. He mainly eats meat, primarily seals, musk oxen, lemmings, fish, as well as whales and walruses. Its body is elongated up to 2.50 m, the neck is long and thin, the head is long and narrow, and the ears are small. Thick fur and a layer of fat under the skin protect the body from the cold. Since polar bears are good swimmers, they have small webs of skin between their fingers. A female bear has cubs in December, usually two. Polar bears live up to 25 years. They live on the southern border of the ice zone of North Asia and North America rare on the mainland.

2. The fastest marine animal is killer whale .

The killer whale develops speed up to 65 km/h. This is a black and white whale from the dolphin family, about 8 meters long and weighing up to 7 tons. The killer whale is called the “killer whale”, but this is unfair: the killer whale only kills its prey, just like other predatory animals.

3. The largest animal is the Blue (blue) whale.

The blue whale is the largest animal on Earth, its length is 35 m, and its weight is about 130 tons. His weight equal to weight 30 elephants, 150 cars or 1600 people. As a result of hunting for them, the number of blue whales has sharply decreased; their number is now estimated at 10,000 heads. The blue whale is on the verge of extinction.

4. The southernmost animal - the Weddell seal .

The Weddell seal lives in the sea, resting on the shore and on the ice floes around Antarctica. It feeds mainly on fish. Length over 3 meters, weight up to 500 kg. He has a rather small head, the color is dark gray-brown, with black spots and margins above, lighter below. In diving, the Weddell seal holds the record. It can dive to a depth of 600m and stay underwater for up to 73 minutes.

5. The largest accumulation of corals - Large barrier reef(BBR).

Corals are creatures of animal origin, scientists classify them as invertebrates. Corals are very different from each other in shape, size and color. In the struggle for living space, corals can intertwine, destroy each other and eventually coalesce. Adding an average of one meter of living space over the course of a century, after a thousand years, corals form reefs. The largest stretches along the east coast of Australia for more than 2000 km. From the point of view of biologists and geologists, this is one of the greatest wonders of the world. He was recognized natural heritage, biosphere and marine park. The Great Barrier Reef resembles a half-submerged fortress wall. This is the largest coral formation in the world: it is so huge that it can be seen from space.

V . The ocean needs protection.

Boundless and great oceans. A serious danger threatens the ocean: drop by drop, substances alien to the oceanic environment rush into the ocean, poisoning the water and destroying living organisms.

Oil is one of the most dangerous pollutants in the ocean environment. Oil pollution is fatal not only for aquatic organisms but also for coastal birds. Many types of bacteria, yeasts, fungi and unicellular algae in the course of their life activity destroy oil products and pesticides, and neutralize some heavy metals. As a result, in the seas, especially in their coastal, shallow water areas, there is a gigantic scale process of water clarification, improvement and maintenance of its quality at a certain level.

However, self-purification processes are not enough for the ocean. Therefore, a person must come to the aid of the cradle of earthly life. The ocean does not belong only to people, so we must constantly take into account the interests of other living beings who use its benefits. And carry out various environmental activities.

(A student's speech about marine reserves is accompanied by a presentation).

1) Far East Marine State Nature Reserve. In 1978, not far from Vladivostok, in the Gulf of Peter the Great, the first state marine reserve in our country was created. The main task of which was the preservation of marine communities and certain types inhabiting the water area richest in marine plants.

Experts count two thousand species of invertebrates, 278 species of fish, about 300 species of birds and about 20 species of mammals in Peter the Great Bay. And although the reserve occupies only 5% of the area of ​​the bay, almost all of this diversity of life forms is represented in it.

2) One of the largest marine reserves in the northwest was created in 2005 and 2006 Hawaiian Islands 140,000 square miles of pristine reefs, shoals and islands.

3) The largest marine reserve is the reserve around the Chagos Islands in the Indian Ocean, the territory controlled by Great Britain and the military base Diego Garcia of the United States of America. The natural reservation covers about 210,000 square miles.

VI . Consolidation and conclusion of the lesson.

In this way, we have proved that life in the ocean is present in all its parts: from the surface to great depths, from coasts to central parts. Determined the conditions that affect the distribution of life in the ocean. 13

***AT let's do the task: Determine which group of ocean inhabitants the following organisms belong to. Read the names of the organism and name the group.

VII . Homework. Paragraph 46.47 answer questions (orally).

And now, at the end of the lesson, let's watch an excerpt from the film aboutlife in the ocean.

VIII . Screening of an excerpt from the film "Inhabitants of the Ocean".

living conditions in the ocean. Ocean water contains all the substances necessary for the life of organisms. Life in the ocean is all pervasive. It exists at the bottom of the Mariana Trench, at a depth of 11 thousand meters, and even where a new earth's crust is formed, where hot magma comes from the depths of the Earth through faults, where high temperatures and great pressure.

The conditions of life in the ocean from the pole to the equator, from the surface to the maximum depths are very different. Therefore, the diversity of life in the ocean is unusually high. Bacteria, unicellular plants invisible to the naked eye, and algae up to 80 m long, microscopic animals and huge blue whales. In terms of the diversity of plant and animal species, the ocean is quite comparable to the land.

The ocean is full hidden life and mysteries that amaze the imagination. Many of them have not been disclosed so far. In the study of the depths of the sea, organisms unknown to science are still being found.

According to most scientists, all life on our planet came out of the ocean, which is why it is called the "cradle" of life on Earth. The development of life in it has led to a change in the properties of water (salinity, gas content). For example, the proliferation of green plants in the ocean that can release oxygen has led to an increase in the amount of oxygen in the water. From the water, he stood out into the atmosphere, changed its composition. The increase in the amount of oxygen in the atmosphere made it possible for the land to be populated by organisms that came from the ocean.

Distribution of organisms in the water column. The conditions for the existence of organisms in the water column and in the bottom areas are different. All marine organisms are divided into three groups according to their habitat conditions. The first includes organisms that live on the surface and in the water column and do not have active means of transportation. The second group consists of organisms that actively move in the water column, and the third group consists of organisms that live at the bottom. Organisms that are in suspension in the water and are not able to resist the transfer by currents are called plankton (translated from Greek - wandering). Plankton is made up of algae and tiny animals. Plant plankton forms real "pastures" on which animal plankton develops.

Many bacteria live in the water column, spreading to the very depths. Thanks to the activity of bacteria, dead organisms decompose, and the substances necessary for the nutrition of living organisms again enter the biological cycle.

Actively moving organisms live everywhere in the ocean. These are the fish marine mammals(dolphins, whales, seals, etc.), squids, sea ​​snakes, turtles, etc.

Life in the water column is unevenly distributed. Most of the living organisms live in the 100-meter surface layer illuminated by sunlight. In this layer, the distribution of life depends on the geographic latitude. Polar waters from behind low temperatures and the long polar night are poor in plankton. A large amount of plankton develops in summer in the waters of temperate latitudes of both hemispheres. Here, currents, strong winds contribute to the mixing and rise of deep waters, enriching them nutrients and oxygen. Temperate latitudes (40 - 60 °) are the most fishy areas of the ocean.

In tropical latitudes, the number of living organisms decreases, since the water on the surface has elevated temperature, salinity and does not mix well with deep water masses. In equatorial latitudes, the number of organisms increases.

Distribution of life on the ocean floor. The organisms of the bottom layers and the bottom itself include algae, corals, crustaceans, worms, mollusks, starfish, etc. Of the fish, flounder and halibut live here; octopuses live. Well-lit and warm coastal areas are especially rich in life. A lot of nutrients come here from the land from the erosion of the coast by waves and currents. Over 99% of the plants and animals living on the planet are concentrated here. seabed. Algae, for example, form huge underwater meadows.

In warm tropical waters, marine invertebrates live at the bottom - corals that form reefs and islands.

biological wealth of the ocean. The ocean has long been the breadwinner of man. In it they hunt mammals, fish, invertebrates, collect algae, catch krill - small marine crustaceans. Marine organisms are not only a source of food, but also medicines, raw materials for the chemical industry.

The world's oceans have a large, but still limited biological wealth, and humanity faces the important task of their rational use, protection and multiplication.

1. What plants and animals do you know that live in the ocean?
2. What is the difference between living conditions in the ocean and living conditions on land?
3. How do humans use marine organisms?

Diversity of marine organisms. The ocean is full of life and mysteries that amaze the imagination. Many of them have not been disclosed so far. In the study of the depths of the sea, organisms unknown to science are still being found.

Life in the ocean is all pervasive. It exists at the bottom of the Mariana Trench, at a depth of 11 thousand meters, and even where a new earth's crust is being formed, where hot magma comes from the depths of the Earth through faults, where there are high temperatures and enormous pressure.

The conditions of life in the ocean from the poles to the equator, from the surface to the maximum depths are very different. Therefore, the diversity of life in it is unusually great. (Prove this based on knowledge from the 6th grade course. Tell us about the living conditions of different groups of organisms.)

A huge number of living organisms live in the World Ocean - from unicellular microscopic plants and animals to sea giants. According to the way of life, marine organisms are divided into three groups: nekton - actively swimming animals; plankton - passively floating and benthos - organisms living on the bottom.

Rice. 26. Fishing areas. Explain the reasons for this fishing geography

Spread of life in the ocean. There are two areas of life in the ocean. The first includes the surface of the water and the entire water column, the second - the bottom of the ocean. What influences the distribution of organisms in the boundless waters of the ocean? Light is the first condition for the existence of green algae in the water, which feed on other organisms. There is less light in water than in air, with depth the illumination decreases. Therefore, the upper 50-meter water column is the most populated. However, even here organisms are distributed unevenly. There are more of them closer to the coast than in the open ocean. On the ocean floor, more organisms also live in shallow coastal depths.

In addition to light, other factors influence the distribution of organisms in the ocean: salinity and density, water temperature, the amount of nutrients, currents, vertical mixing of water, as well as the properties of the rocks that make up the seabed. All these conditions are combined in different ways in the vast expanses of the ocean. For example, in areas of rising deep waters, the surface layer is fertilized with nutrients, which creates favorable conditions for life. Storm winds and currents contribute to the rise and mixing of waters. In those parts of the ocean where winds are rare, surface waters sink deeper, they are poor in nutrients. There is little plant and animal plankton, as well as fish.

Rice. 27. Collecting shellfish

In the ocean, as well as on land, there is an alternation of belts with increased and decreased mass of living organisms. The greatest accumulation of life in the ocean is characteristic of subpolar and temperate latitudes.

In the ocean, in contrast to land, where animals coexist with plants, there are no green plants below depths of 200-250 m. Here the ocean is inhabited only by animals and bacteria. The distribution of life in the ocean depends on the rate of supply of nutrients with upward movements of water, i.e., to a large extent depends on the movement of waters.

biological wealth of the ocean. The ocean has long been the breadwinner of man. In it they hunt mammals (seals, walruses), fish, invertebrates, and collect algae. Marine organisms are used not only for food. Medicines and raw materials for the chemical industry are obtained from them.

The world's oceans have a large, but still limited biological wealth, and humanity faces the important task of their rational use, protection and multiplication.

Rice. 28. The ocean is rich in fish

1. What is the peculiarity of the spread of life in the ocean?
2. What determines the distribution of organisms in the surface layer of water?
3. What parts of the ocean are especially rich in life? Explain why.
4. Why does life in the ocean require protection?

Ocean water contains substances necessary for life. Living beings are found in the ocean at any depth. They exist even at the bottom of the Mariana Trench - the deepest point of the World Ocean - at a depth of 11 thousand meters, even where hot magma comes from the depths of the Earth through faults, even where there are high temperatures and enormous pressure. We can safely say that life in the ocean is all-pervasive.

Life in the ocean is extremely diverse - more than 200,000 species of organisms live there, due to the fact that its conditions are very different from the poles to the equator, from the surface of the water masses to the deep ones. In terms of the diversity of plant and animal species, the ocean is comparable to land. The ocean is still full of mysteries even now. When studying the depths of the sea, organisms unknown to science are found.

Inhabitants of the oceans

According to the conditions of their habitat, all inhabitants of the World Ocean can be grouped into 3 groups:

1) Organisms that live on the surface of the ocean and in the water column and do not have active means of movement (plankton).

2) Organisms actively moving in the water column (nekton).

3) Organisms living on the bottom (benthos).

Plankton

An analysis of living organisms and their habitats suggests that the ocean is inhabited by organisms unevenly. Especially densely populated are coastal areas with depths of up to 200 meters, well-lit and warmed by the sun's rays. On the mainland, you can see forests and meadows of algae - pastures for fish and other inhabitants of the ocean.

Away from the coast, large algae are rare, since the sun's rays hardly penetrate the water column. Plankton reigns here (Greek planktos - wandering). These are plants and animals that are not able to withstand currents that carry them over considerable distances. Most of these organisms are very small, many of them only visible under a microscope. There are phytoplankton and zooplankton. Phytoplankton are various algae. Zooplankton inhabits the entire water column: these are small crustaceans, numerous protozoa.

Plankton is the main food of most ocean inhabitants. Naturally, areas rich in it are also rich in fish. Baleen whales can also live here, in the diet of which plankton occupies the main place.

Actively moving organisms live everywhere in the ocean - nekton (Greek nektós - floating, floating) nekton includes most fish, pinnipeds (seals and walruses), cetaceans (whales, sperm whales), cephalopods (squids, octopuses, etc.), sea snakes and turtles. All nektons usually have a well-streamlined body shape that helps them move quickly in the water.

Benthos lives at the bottom of the sea or ocean (Greek benthos - deep). This is a collection of plant and animal organisms that live on the ground or in the soil of the seabed. Benthos include brown and red algae, mollusks, crustaceans and others. Benthos serves as food for many fish and other aquatic animals.

In the distribution of benthos, vertical zonality is observed: mollusks and crustaceans predominate in the upper horizons, mollusks and echinoderms dominate in the middle ones, and crustaceans and echinoderms predominate in deeper ones.

ocean depths

The depths of the ocean are sparsely populated, but they are not lifeless. Of course, there are no plants there anymore, but amazing fish swim in complete darkness, under great pressure, in cold water: they have huge toothy mouths, luminous bodies, and “lanterns” on their heads. Some of them are blind, others can barely see in the dark. They feed on the remains of organisms falling from above, or eat each other.

accommodation life

Life in the ocean is distributed unevenly not only in depth, but also depending on geographic latitude. Polar waters are poor in plankton due to low temperatures and long polar nights. Most of it develops in the waters temperate zone both hemispheres. Here the currents strong winds contribute to the mixing of water masses and the rise of deep waters, enriching them with nutrients and oxygen. Due to the strong development of plankton, various types of fish also develop, therefore temperate latitudes- the most fishy areas of the ocean. In tropical latitudes, the number of living organisms decreases, since these waters are very warm, highly saline and poorly mixed with deep water masses. In equatorial latitudes, the number of organisms increases again. The ocean has long been the breadwinner of man.

The work was prepared by a student of 6 "a" class Khrabrov Nikita