Which crustaceans are of commercial importance. Diversity of crustaceans, their role in nature and human life

Subject: Diversity of Crustaceans, their role in nature and human life.

Target: consider the diversity of crustaceans, their role in nature and human life.
Exercise:
Get acquainted with different types of crustaceans, their structural features, and habitat.
Consider the classification of crustaceans..
Determine the importance of crustaceans in nature and human life.
Have a creative and interesting time

Basic concepts: orders Decapods, Isopods, Cladocera, Copepods, Leafpods, Carpoeds.
Equipment and materials: posters with images of crustaceans, handouts for student work, a biology textbook for grade 8, diagrams, drawings, tables, multimedia board, videos, presentation
Form of organization of educational activities: cool lesson.
Lesson type: mastering new knowledge.
During the classes

I .Organizing time . Greetings to the participants. Announcing the topic and purpose of the lesson. Good day everyone! I'm glad to see everyone in our lesson
II Updating the basic knowledge and skills of students.
1) Brainstorming method
1. What parts does the cancer body have? (cephalothorax and abdomen).
2. How many pairs of walking legs does a crayfish have? (five)
3. What shape is the cancer heart? (Shapes of a five-pointed pouch)
4. In what part of the cancer body are the excretory ducts located?
glands? (On the head)
5. How do crayfish reproduce? (Calf throwing)
6. Where do crayfish spend the winter? (In the hole)
7. How long do crayfish live? (20-30 years)
8. How many times a year does a crayfish molt? (1-2 times)
9. Respiratory organs of cancer. (Gills)
10. Olfactory organs of cancer. (Long mustache)
11. Cancer circulatory system. (Unclosed)
12. Digestive system of cancer. (Food is digested in the stomach, which consists of two sections)

2) Make a logical chain “Digestive system of crayfish”

Oral opening→ pharynx→ esophagus→ stomach → intestines → anal hole

III . Motivation of educational and cognitive activities of students

... Such a number of legs, such means of transportation - and all this in order to move backwards! F.Krivin

People say he backs away like a cancer. How can this be explained? The peculiar appearance of our new acquaintance, the crayfish, has led to the well-known misunderstanding about where his eyes are and why, when moving, he does not crawl forward, but backs away. This misunderstanding contributed to the emergence of an original legend about why cancer’s eyes were in the wrong place.

Cancer kept asking God to give him such huge eyes as those of an ox. The Lord gave him small eyes. “They can only be attached from behind,” said the offended cancer. The Lord left the crayfish with small eyes, but made it move forward with its tail, and it turned out as if the crayfish had eyes behind it.

Problematic issues: Do you think cancer has relatives? Are they similar to the crayfish we know? Where can you find them? What they are and who they are, today we will find out in class. So, the topic of our lesson...
Slide 1
Topic: Diversity of crustaceans, their role in nature and human life.
Purpose: to consider the diversity of crustaceans, their role in nature and human life.
Slide 2,3,4 Assignment: Get acquainted with various types of crustaceans, their structural features, and habitat. Consider the classification of crustaceans. Determine the importance of crustaceans in nature and human life. Have a creative and interesting time.

IV. Students' perception and assimilation of new material.
Slide No. 5,6,7

There are more than 50 thousand crustaceans in the world, which can be found where you wouldn’t even expect them. So, we are going on a virtual journey into the world of crustaceans. The class was divided into four groups in advance. Consultants were selected from each group. Each group received a task. Prepare a presentation. Determine the structural features and vital functions of representatives of a certain order. Their importance in ecosystems. 4 groups: 1) detachment Decapods; 2) order Cladocera; 3) orders Phytopods, Copepods; 4) orders Isopods, Carpoeds
Today we, a group of researchers, decided to find out everything about the representatives of the class Crustaceans: how many there are, where they live and what they are. To do this, we will take a short trip, during which we will study representatives of crustaceans.

Slides No. 8-12Order Decapods.
The most famous order is Decapods. The body (length 0.3-80 cm) is of various shapes, divided into a cephalothorax and abdomen, on the head there are 2 pairs of antennae and eyes, and they have 5 pairs of walking legs. Several species of hermit crabs live in the Black Sea. Young crustaceans that have just hatched from eggs find gastropods with shells of appropriate sizes, kill and eat the host, and hide their abdomen in an empty shell.
Now look at this amazing specimen - the invisible crab. Invisible - because it is almost impossible to see it among the algae. This lean, long-legged crab is a master of camouflage. He carefully places small bushes of algae on his shell. So it wanders unnoticed in its “camouflage.” Shrimp, widespread in all seas and oceans, are found in some fresh water bodies. The greatest species diversity is in tropical seas. Found in the Black and Azov Seas.
Paleontologists have discovered the fossilized remains of a shrimp that lived on the planet about 360 million years ago. Thus, this find became the oldest among the fossil species of decapods.

Slidey No. 13-14Order Cladocera
A group of ancient and primitive crustaceans, there are about 1,500 species. The body (length 0.1-10 mm) is divided into a head and a trunk, partially or completely, covered with a bicuspid chitinous shield. The antenules are small, the antennae (antennae) are well developed, bibranched with setae, and are used for swimming. Distributed mainly in fresh water bodies. Representatives of this series are daphnia. Their sizes are very small: the body (1-3mm) of daphnia is enclosed in a translucent bivalve shell. Daphnia swim with the help of a second pair of antennae, jumping (for this they are also called “water fleas”). On their head there are two complex and one simple eye. Filtration feeding. Daphnia play an important role in the biocenoses of fresh water bodies, because they are the main food base of many
aquatic organisms, this is food for aquarium fish, this is an object of study.

Slide No. 15 Order Phytopods The body of these large crayfish (up to 5 cm long) is covered with a large shield.
Shrews usually live in small temporary bodies of water, swimming almost all the time with their ventral side down. However, a lack of oxygen can cause them to float on their backs near the surface of the water, since scale insects breathe using gills on their legs. They are omnivores. They consume not only plankton, but also large prey, including worms, midge larvae, and even weak tadpoles.
Shchitni live in temporary reservoirs. When ponds dry up during certain times of the year, in the absence of rain, the adults die during this drought and the eggs remain dormant (up to 9 years) until rains refill the ponds, allowing them to hatch. Dried shield eggs are easily dispersed by the wind, which ensures the spread of the species.

Slide No. 19-21
Importance in crustacean ecosystems
Almost all fish, both marine and freshwater, rely heavily on crustaceans for their existence. For the giants of the sea - toothless whales - crustaceans serve as the main food.
Crustaceans play a very important role in the economy of nature. Organic substances in water bodies are created mainly due to the activity of microscopic algae. Crustaceans eat these algae and are, in turn, eaten by fish. . On the other hand, they use huge masses of dead aquatic animals for food, thus ensuring the purification of the reservoir.
Many crustaceans are directly used by humans as valuable food products. In many countries, fishing for shrimp, crabs, lobsters, lobsters and other edible species is developed. Recently, successful experiments have been carried out using marine planktonic crustaceans to obtain vitamins, fats and other important substances. Some types of crustaceans necessary for feeding young fish are bred at fishing factories.

Slide No. 24-28.
This is interesting!
The largest of all crustaceans (but not the heaviest in weight) is considered the “giant sea spider,” which is called the “crab on stilts.” It is found in deep sea areas on the southeast coast of Japan. Adults of this species typically measure 254mm by 305mm, and their claws range in size from 2.43 to 2.74m.

A rather interesting event occurred in Australia: the world’s largest crab, weighing 6.8 kg, was caught off the coast of this continent. The width of this unique specimen at the moment reaches 38 cm.
Unusual in appearance, but at the same time, a beautiful crustacean monster, due to its huge size, received the name Tasmanian king crab And immediately there were societies that wanted to get this specimen of the crab - the British Sea Life Aquarium in the city of Weymouth bought it for $5,000, and now the largest crab in the world is a valuable exhibit in the aquarium.
The largest among lobsters and the heaviest among crustaceans is the American lobster (Homarus amerikanus). On February 11, 1977, a lobster weighing 20.14 kg and 1.06 m long was caught in the New Stockade area, Canada. The lobster was later sold to a restaurant owner in New York.
A British expedition discovered the largest shrimp in the world in the waters of the Pacific Ocean, off the coast of New Zealand.
The length of this largest representative of crustaceans in its type was as much as 28 centimeters, while ordinary shrimp do not reach a length of more than 2-3 centimeters.

The smallest crustacean is the water flea (from the genus Alonella), measuring less than 0.25 mm in length. She lives in UK waters.
The smallest known lobster is Homarus capensis, living in southern Africa. Its total length is only 10-12cm.
the smallest crabs in the world - the so-called "pea crabs". Some species of these crabs have a shell size of 6.3 mm.
The longest-living crustacean is the American lobster (Homarus amerukanus). The largest representatives of this species live up to 50 years.

Slides No. 29-31
Folk wisdom

Whom does grief paint?
Not a blacksmith, but with tongs.
To avoid getting into trouble, he holds scissors in water.
Who has a mustache longer than his legs?
Not an egg, but in a shell, not a cat, but a mustachioed one.
Sitting aground, wiggling his mustache,

And he will go for a walk - backwards.

Crawling backwards, backwards

Everything under water is enough for claws
Proverbs and sayings
Only the crayfish move back.
Grief paints one cancer.
Cancer is especially scary because it is behind the eye.
It’s a miracle, not crayfish: they climb into the bag themselves.
Then it will be like a crayfish whistling in a pond.
Without fish and cancer, fish.
I went to the bottom to catch crayfish.
It doesn't matter what pot it is cooked in.
God had mercy on the cancer and gave him eyes in the back.
The cancer took pity on the frog and tore out its eyes.

While members of one team report on a particular order of crustaceans, others write down in a table all the species they hear or see.

Why are representatives of the class Crustaceans combined into one class?
2. Game "Field of Miracles"
This copepod received its name in honor of the mythical one-eyed giant.
What is it called?

(Cyclops)
On the desk:
3.Find the “extra” animal among those named:
crayfish, crab, daphnia, lobster, shrimp, lobsters.
4.Decipher which crustaceans are hiding behind the mixed up letters:
tsykrimo; winds; Tiguslan
(Woodlice) (shrimp) (lobster)

5. “Find out the name”, take a set of letters and make an anagram in a group, others guess

POIDROKO
MORA
TYGUSLAN
NIIDAF
KBAR
KRIMOTSY
WINDCRACKS
TISHCHIN

7. The basis of arthropod integument is organic matter
a) chitin; b) murein; c) starch; d) cellulose.

8. Body cavity of arthropods:
a) mixed; b) parenchyma; c) secondary; d) primary.

9. Nervous system of arthropods:
a) nodal; b) diffuse; c) stem; d) looks like a tube.

10. Excretory organs of crustaceans:
a) kidneys b) metanephridia; c) green glands; d) Malpilgian vessels.

11. Respiratory organs of crustaceans:
a) gills; b) trachea; c) pulmonary sacs; d) gills and lung sacs.

12. Note the number of pairs of limbs located on the head of the crayfish:
a) three; b) five; at seven o'clock; d) nine.

VII. Lesson summary.
- What are your impressions of the lesson?
- What did you like most?
- What interesting things did you learn?
- What methods would you like to use in the next lesson?
VIII. Student assessment.
At the beginning of the lesson, students are given tokens for each group; With correct answers, the commander gives tokens to a specific student.
At the end of the lesson, grades are given based on the number of tokens the students received.

IX. Homework .
Work through paragraph 20
Write a miniature essay on the topic “The fate of crustaceans in the future”

Objectives: - ensure the assimilation of knowledge about the basics of their classification (main classes of type), features of adaptation to the environment; - continue to develop the skills to observe, recognize arthropods in nature, in tables, drawings, in collections, and compare them with each other; - develop skills in working with textbooks and additional literature.

Type Arthropods Subtype Gill-breathing Class Crustaceans (Primary aquatic arthropods) Subclass Lower CrustaceansSubclass Higher Crustaceans Order Branchiopods (branchopods) Order Stomatopods (crayfish - mantises) Order Phytopods (shields) Order Isopods (woodlice, water burro) Order Cladocera (daphnia) Order Miscellaneous legs (amphipods) Order Copepods (Cyclops) Order Euphausiae Order Caproeds (carpoeds) Order Decapods (crayfish, lobster, shrimp, crab) Order Cirripedes (sea acorns, barnacle) Order Shelly crustaceans.

Lower crustaceans Order phyllopods Shchitni have 70 pairs of legs. Biologists consider shields to be living fossils (relics), since their appearance has remained virtually unchanged for 200 million years. Moreover, the average “lifetime” of an individual species is no more than several million years. Swimming organs - pectoral legs

Lower crayfish Order Cladocera Daphnia "water flea" Swimming organs - the second branched pair of antennae In ponds and puddles of central Russia, the following crustaceans of the genus Daphnia are often found (and most popular among aquarists): Daphnia magna (D.magna), female up to 6 mm, male up to 2 mm, newborns 0.7 mm. They ripen within 24 hours. Litters every other day. There are up to 80 eggs in a clutch (usually 20-30). Life expectancy is up to 3 months. Daphnia pullex (D.pulex), female up to 3-4 mm, male 1-2 mm. Litters in 3-5 days. There are up to 25 eggs in a clutch (usually 10-12). They live for days.

Lower crayfish Order Copepods Cyclops Swimming organs - the first unbranched pair of antennae Different types of Cyclops can be from 0.6 to 5.5 mm in length. In females, the egg sacs are located on the abdomen. They live among the plants of the coastal strip of standing reservoirs. They feed on plankton. Development goes through several larval stages. They play an important role in fish nutrition.

Sea acorns (balanus) Lower crayfish Order Barnacles The diameter of the shell-house of different species is 1-11 cm. The house is formed by calcareous plates surrounding the body of the crustacean. Motionlessly sessile (on a hard substrate) marine animals. Filter food particles from the water using the pectorals. Hermaphrodites. The main culprits of fouling on the bottoms and sides of sea vessels.

Sea ducks, also known as sea truffles. They look like shellfish. But in fact, these are crayfish, and the tentacles are their legs. With the help of legs extended from a shell that resembles a shell, the sea duck sticks to the rocks. Or to the bottoms of ships. In a particular case, ducks settled on a sunken pillar. Which for some reason floated up and washed up on the coast of Wales. Monsters that are so scary in appearance are actually a delicacy. They are eaten with pleasure in Portugal and Spain. Where they catch it on purpose. And they sell for $300 per kilogram. Sea ducks have juicy pinkish-white meat. Steamed, they taste like both an oyster and a lobster. These crayfish can also be eaten raw, whoever does not disdain them. Lower crayfish. Order barnacles. Sea duck.

Lower crayfish Order Shelly crayfish Modern representatives of this order are small: no more than 1-2 mm, a few up to 6 mm. All inhabitants of water, some fresh, some sea. They feed primarily on animal matter, especially the carcasses of aquatic animals. Their significance for humans is the same as that of other lower crustaceans, that is, they serve as food for fish.

Mantis crab Higher crustaceans Order Stomatopods Named for some similarity with insect mantises. mantises Length up to 20 cm. Lives in the Mediterranean Sea. Lives at the bottom in burrows. Predator; grabs prey (crustaceans, mollusks) with its highly developed second pair of thoracic legs. It has commercial significance.

Higher crayfish Order isopods. Water burro (similar to land woodlouse) woodlice Typically 1 - 1.2 cm in length. Found in stagnant or slowly flowing freshwater bodies, as well as in brackish waters; among plants or at the bottom of reservoirs. Feeds on dead plants (detritivores). Up to 1.8 cm in length. Found on land in damp places. It feeds on dead leaves and rotting wood - a detritivore. Plays an important role as a destroyer of dead organic matter and in soil formation.

Amphipod Higher crayfish Order Multipeds About 1.3 – 1.7 cm in length. Amphipods include benthic and planktonic life forms. Quite demanding in terms of oxygen and lime content. It feeds mainly on plants, as well as carrion. Amphipods are filter feeders and use antennae. During its almost 10-month life, it bears offspring 6-9 times. The main food of fish. “Lying on its side”, they glide at the bottom of the reservoir using the last pair of pectoral and first three abdominal legs for swimming.

Whales feed on small crustaceans - krill. The composition of krill includes euphausian crustaceans measuring 10-65 mm. A specimen can reach a length of 6 cm and a weight of 2 g, cmg life expectancy is up to 6 years. Life-flight Feeds Antarctic krill feeds on plankton. plankton At the same time, krill itself is food for fish , penguins and penguins and other species of marine fauna. fauna Higher crayfish Order Euphausiaceae

Kamchatka "crab". One of the largest Far Eastern crabs, it is a commercial object. Not a true crab, it belongs to the family of crab-shaped hermit crabs, related to hermit crabs. The main difference from real crabs is the fifth pair of walking legs hidden under the carapace, that is, not 4, but 3 pairs of limbs are used for movement. carapace It inhabits the Sea of ​​Japan, Okhotsk and Bering Sea. The male carapace is on average 16 cm wide, and in the Gulf of Alaska 28 cm. The distance between the ends of the average walking legs of large individuals is 1.5 m, and the total body weight is up to 7 kg. GIANT CANCER

A 140-year-old, 20-pound giant lobster named George left the aquarium of a posh seafood restaurant on Park Avenue in Manhattan at the request of the animal rights group People for the Ethical Treatment of Animals (PETA). GIANT CANCER

Lobster Some decapods live a long time: American lobster up to 50 years, broad-toed crayfish up to 20 years, Kamchatka crab up to 23 years, lobster over 15 years, mitered crab up to 6, sometimes up to 10 years, palm thief more than 10 cm long has no birth less than 5 years, shrimp usually do not exceed 4 years, and small species do not live up to a year. Higher crustaceans Order decapods

GIANT CRAWLISH Lobsters are common in warm seas. Body length up to 60 cm. Similar to lobsters, but lacking claws. Lobsters body and thick antennae are equipped with powerful spines. In the first year of life, it molts about ten times. The new shell hardens with spikes within 2-3 weeks. Lobster meat is considered a delicacy.delicacy

Crayfish are an inhabitant of clean water bodies. Usually about 12 – 16 cm in length. Coloring is variable. The lifestyle is crepuscular: in shelters during the day, crawling along the bottom at night in search of food - small animals, plants and carrion. In case of danger, it makes sharp strokes with its belly and quickly swims away with its rear end forward. Mating in autumn. The female takes care of the offspring by attaching fertilized eggs to her abdominal legs. The larvae hatch in May of the following year and quickly develop into crustaceans about 1 cm in length.

What fable is simply unthinkable without it? Why, despite the insignificant size of the Calanus crustaceans, do huge whales feast on them? The stomach of a blue whale can hold up to 1.5 tons of planktonic “porridge.” One clutch of a female daphnia contains approximately 60 eggs. After 15–20 days, young daphnia hatch, which are soon able to lay eggs themselves. How many daphnia can approximately appear from one young female in three summer months? It crawls backwards, backwards, everything is under water, it grabs with its claw. There is a huge crayfish in the sea. Guess what it's called? He lives at the bottom of the sea. Moves forward sideways. The claws cut like a knife, similar to a large spider. Looks like a big spider. What animal wears a tailcoat? Cancer - tailcoat Who looks at cancer through a telescope? Constellation Cancer - astronomer Emblem on the uniform cap of sailors Good luck!!! plankton

The importance of crustaceans in nature

Crustaceans play an important role in the biological cycle in aquatic ecosystems.

Planktonic crustaceans are a necessary link in the food chains of marine animals. They feed, as a rule, on single-celled algae and organic particles suspended in the water. In turn, fish feed on planktonic crustaceans. In all reservoirs, the basis of fish nutrition is crustaceans, as well as the animals that feed on them.

Example 1

Toothless whales eat large quantities of small crustaceans, straining them out of the water. Some fish, such as sprat, herring, sprat, etc. feed on planktonic crustaceans throughout their lives. Bottom-dwelling fish use mysids and amphipods as food.

Diaptomus, cyclops, daphnia, and amphipods are the main food of freshwater fish.

Isopods feed mainly on detritus and plant debris and contribute to the destruction of organic residues. Therefore, they play a significant role as saprophages in biocenoses.

Crustaceans take part in the biological purification of water, being the largest group of biofilters and detritivores. Crustaceans purify water by straining it with their thoracic limbs. Thus, calanus crustaceans, as filter feeders, feed on very small organisms or single-celled algae.

Woodlice are able to process plant residues, while fertilizing the soil with organic compounds and improving the soil structure. Among the crustaceans there are species:

Example 2

The importance of crustaceans in human life

Crustaceans are an important fishery object. They are used by humans for food. The most important fisheries are crabs, shrimps, and lobsters. In the Far East, mantis crayfish are eaten as food. Marine crustaceans are used to prepare protein paste. Fishing for large stomatopods is carried out in the Indian and Pacific Oceans. The harvest of decapod crustaceans in the world reaches 700 thousand tons per year. Most of the production is carried out in Japan, China, India, and the USA. In Russia they harvest shrimp, Kamchatka crayfish, and river crayfish. Crustaceans consumed by humans are a source of vitamins A and D, iron, calcium, and zinc. The nervous system is strengthened, vision improves, and the risk of tumors is reduced.

At fish hatcheries, small crustaceans are bred in large quantities as food for juveniles and fish (order Lamp-Armored).

Example 3

Artemia crustaceans are bred as food for aquarium fish, and are currently widely used for fattening young sturgeon fish in fish hatcheries. Cladocerans are also a food source for many species of fish. Daphnia is bred to feed young fish.

Amphipods provide valuable food for fish. In Russia, work is being carried out to acclimatize amphipods to water bodies where they have not previously lived.

During the molting process, crustaceans shed their calcareous exoskeleton, which is gradually deposited on the bottom and participates in the formation of chalk and limestone deposits.

Some species of crustaceans are used as biomonitors and bioindicators. For bioindication, planktonic forms and crayfish are most often used. In this case, the physical parameters, ionic composition of water, and its suitability in fresh ecosystems are determined.

Cyclops, on the one hand, play an important role, being a valuable food for fish and their young, and, on the other hand, they are intermediate hosts of the helminths Guinea worm and tapeworm.

Some types of woodlice cause significant damage, destroying wooden buildings.

Note 1

Species of crustaceans that lead an attached lifestyle (for example, sea acorns) cause damage to ships by growing on the bottom and destroying structures. Wood-boring crustaceans contribute to the destruction of wooden structures in the sea.

The importance of crustaceans in nature

Crustaceans play an important role in the biological cycle in aquatic ecosystems.

Planktonic crustaceans are a necessary link in the food chains of marine animals. They feed, as a rule, on single-celled algae and organic particles suspended in the water. In turn, fish feed on planktonic crustaceans. In all reservoirs, the basis of fish nutrition is crustaceans, as well as the animals that feed on them.

Example 1

Toothless whales eat large quantities of small crustaceans, straining them out of the water. Some fish, such as sprat, herring, sprat, etc. feed on planktonic crustaceans throughout their lives. Bottom-dwelling fish use mysids and amphipods as food.

Diaptomus, cyclops, daphnia, and amphipods are the main food of freshwater fish.

Isopods feed mainly on detritus and plant debris and contribute to the destruction of organic residues. Therefore, they play a significant role as saprophages in biocenoses.

Crustaceans take part in the biological purification of water, being the largest group of biofilters and detritivores. Crustaceans purify water by straining it with their thoracic limbs. Thus, calanus crustaceans, as filter feeders, feed on very small organisms or single-celled algae.

Woodlice are able to process plant residues, while fertilizing the soil with organic compounds and improving the soil structure. Among the crustaceans there are species:

Example 2

The importance of crustaceans in human life

Crustaceans are an important fishery object. They are used by humans for food. The most important fisheries are crabs, shrimps, and lobsters. In the Far East, mantis crayfish are eaten as food. Marine crustaceans are used to prepare protein paste. Fishing for large stomatopods is carried out in the Indian and Pacific Oceans. The harvest of decapod crustaceans in the world reaches 700 thousand tons per year. Most of the production is carried out in Japan, China, India, and the USA. In Russia they harvest shrimp, Kamchatka crayfish, and river crayfish. Crustaceans consumed by humans are a source of vitamins A and D, iron, calcium, and zinc. The nervous system is strengthened, vision improves, and the risk of tumors is reduced.

At fish hatcheries, small crustaceans are bred in large quantities as food for juveniles and fish (order Lamp-Armored).

Example 3

Artemia crustaceans are bred as food for aquarium fish, and are currently widely used for fattening young sturgeon fish in fish hatcheries. Cladocerans are also a food source for many species of fish. Daphnia is bred to feed young fish.

Amphipods provide valuable food for fish. In Russia, work is being carried out to acclimatize amphipods to water bodies where they have not previously lived.

During the molting process, crustaceans shed their calcareous exoskeleton, which is gradually deposited on the bottom and participates in the formation of chalk and limestone deposits.

Some species of crustaceans are used as biomonitors and bioindicators. For bioindication, planktonic forms and crayfish are most often used. In this case, the physical parameters, ionic composition of water, and its suitability in fresh ecosystems are determined.

Cyclops, on the one hand, play an important role, being a valuable food for fish and their young, and, on the other hand, they are intermediate hosts of the helminths Guinea worm and tapeworm.

Some types of woodlice cause significant damage, destroying wooden buildings.

Note 1

Species of crustaceans that lead an attached lifestyle (for example, sea acorns) cause damage to ships by growing on the bottom and destroying structures. Wood-boring crustaceans contribute to the destruction of wooden structures in the sea.