EntranceA message on the topic of the diversity and importance of crustaceans. Lesson summary "diversity of crustaceans and their significance"
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
Municipal state educational institution Lizinovskaya secondary school
Development of an open lesson on the topic:
“The diversity of crustaceans, their significance in nature and human life”
Class – 7
Lesson developed by teacher
biology-chemistry
Kurochkina Tatyana Andreevna,
2014
Theme: “The diversity of crustaceans, their significance in nature and human life.”
Lesson type: combined
Target:
to form theoretical knowledge about the structural features and vital functions of crustaceans in connection with their habitat;
reveal the significance of crustaceans in nature and human life.
Tasks:
Educational
– consider the structural features of arthropods using crustaceans as an example;
Reveal the characteristic features of the structure and life processes of crustaceans;
To introduce the diversity of crustaceans and their significance in nature and human life;
Developmental
Develop logical thinking;
Ability to establish cause-and-effect relationships; ability to compare and generalize.
Independent work skills;
Develop students' communication abilities (communication skills).
Educational
Foster a work culture;
Ecological culture, a culture of respect for nature.
Methods:
Verbal – mini-lecture (students’ messages, teacher’s explanation)
Visual – photographs, pictures, drawings from presentation work
Method of independent work in groups
Method of collective solution of creative problems
Equipment:
Microscope, micropreparations (daphnia, cyclops), “living drop” culture
Laptop, projector, presentation; task packages.
Main stages of the lesson
Stage name
Main content
time
1.Organizational moment
The teacher’s word, the psychological attitude of students for success
2 minutes
2. Survey on the material covered
Work in small groups with an individual task (package), results on the board for verification, grading of the group by the “leader”
(method of independent work in groups, method of solving creative tasks)
min
3.Main material (new)
Student message (mini-lecture) with students writing in their notebooks on the issue"The diversity and significance of crustaceans." (Use of images of animals, examination of micropreparations with crustaceans)
General characteristics of crustaceans
physical minute
min
4. Fastening
Control of acquired knowledge - testing with verification using a key.
5 minutes
5. Homework assignment
analyze issues that caused difficulties for discussion in the next lesson
3 min
During the classes:
Organizing time - welcome speech from the teacher
knowledge updating survey
To repeat questions from the material covered, we will split into groups of 4-3 people and choose a leader who will be trusted to evaluate our knowledge.
Group 1 task – “general characteristics of arthropods” the result should be displayed on the board in the form of a crossword puzzle.
Questions for the crossword:
symmetry of cancer body...
Cancer has a body cavity...
The body of animals is……..e.
The body cover consists of...
Group 2 task – “external structure of crayfish”, the result is displayed on the board in the form of a table (filling out the table).
Cancer body parts
Structural features
Veils
chitin
Two, cephalothorax and abdomen
Number of walking legs
5 pairs
Number of abdominal legs
4-5 pairs
Group 3 task – “internal structure of a crayfish”, card “revive the crayfish”: put the internal organs of the crayfish in a certain order.
Group 4 task – justify the correctness or incorrectness of expressions involving crayfish (“you will find out where crayfish spend the winter”; “wait for the crayfish to whistle on the mountain”; “the swan rushes into the clouds, the crayfish moves back, and the pike pulls into the water”).
When ready, students come to the board and show their results (! The results are discussed together).
The “leader” gives grades to the members of his group.
Main material
You need to understand 3 questions: 1) crustaceans are a large group (about 30 thousand species) leading different lifestyles. 2) the importance of crustaceans. 3) general characteristics of crustaceans.
Students make a message, and listeners make notes in their notebooks according to the following scheme:
The name of the crustacean - lifestyle - meaning.
Example:
Daphnia is a free-living, freshwater form - food for fish.
Cyclops is a free-living, freshwater form and an intermediate host of the broad tapeworm.
Cancer is a water orderly.
Shrimp are food for humans.
Sea acorn - damage to the bottom of ships.
Working with a microscope (Daphnia, Cyclops - freshwater forms)
General characteristics - animals with mixed cavity, bilateral symmetry. Body parts: cephalothorax and abdomen. The body is segmented.The limbs are jointed and bibranched. Two pairs of antennae. Gills. The circulatory system is not closed. The nervous system is similar to that of annelids (peripharyngeal ring and ventral nerve cord). Organ for secreting steam from green glands.
There are about 20-30 thousand species in total.
Physical exercise in class
4. Fastening: testing will show how we have mastered the material - the “crustaceans” test
1. Crustaceans are...
b) terrestrial animals
a) daphnia, shrimp, woodlice
b) large pond snail
c) Cyclops
A) digest food
B) both answers are correct
B) move away from danger
A) breathe using gills
C) both answers are correct
9. As a result of gas exchange...
B) all answers are correct
14. The heart of arthropods...
A) two-chamber
B) tubular
B) three-chamber
Reply to test "crustaceans"
the work is completed more than 90% - “5”
80% - “4”
by 70% - “3”
Home task: those questions that caused difficulty in understanding at home, we will return to their discussion in the next lesson.
Thanks everyone for your work!
Lesson appendix
1. Consolidation of the material covered
Test "crustaceans"
To get a “5” you must answer at least 90% of the questions correctly, “4” - no less than 80% of the questions, “3” - no less than 70% of the questions.
1. Crustaceans are...
a) animals capable of flight
b) terrestrial animals
c) mostly aquatic animals
2. Representatives of crustaceans include...
a) daphnia, shrimp, woodlice
b) large pond snail
c) Cyclops
3. Cancer is characterized by molting, which is a process...
A) changes in the outer integument of an animal
B) moving backwards
B)removal of undigested food debris
4. Sense organs help crustaceans...
A) digest food
B) both answers are correct
B) move away from danger
5. Crustaceans are adapted to life in water, since...
A) breathe using gills
B) the abdomen ends with a caudal fin
C) both answers are correct
6. The defense organ of crayfish is...
a) eyes b) long antennae c) claws
7. In fresh water bodies, fish fry eat...
A) daphnia, cyclops b) woodlice c) shrimp
8. The organs for excreting cancer are...
A) green glands b) kidneys c) intestines
9. As a result of gas exchange...
A) carbon dioxide is removed from the body
B) the cancer body only receives atmospheric oxygen
C) oxygen comes from the environment and carbon dioxide is released into the environment
10. The sense organs of crayfish include...
A) organs of vision, hearing, touch b) respiratory organs
B) all answers are correct
11. Arthropods originated from...
A) annelids b) flatworms c) roundworms
12. In crayfish, there are different types in the body...
A) three departments b) two departments c) four departments
13. The high precision of movements of most arthropods is associated with...
A) with the advent of body segmentation
B) with the appearance of chitinous cover
B) with the appearance of muscle bundles
14. The heart of arthropods...
A) two-chamber
B) tubular
B) three-chamber
15. Of the listed crustaceans, the ones that live on land…
A) woodlice B) daphnia C) cyclops
Reply to test "crustaceans"
2. Tasks for questioning and updating knowledge on the topic “General characteristics of arthropods. Peculiarities of the structure and vital processes of crustaceans using the example of crayfish.”
Task No. 1.(creative tasks for collective solution)
There is an expression
1) “You will find out where crayfish spend the winter!”
Where do crayfish spend the winter?
2) “The swan rushes into the clouds, the crayfish moves back, and the pike pulls into the water.”
Is cancer moving backwards?
3) “Wait for the cancer to whistle on the mountain!”
Can cancer climb a mountain?
Can cancer whistle?
(
When the cancer whistles on the mountain” - this is what they say, meaning: “it is unknown when”; "in an indefinite future tense", "never". The saying means the impossibility of doing something. The creators of this Russian proverb were sure that crayfish living on the river bottom would not leave their habitat, would not come to land, and certainly would not whistle. Do crustaceans whistle? Among crustaceans, there are about forty thousand different species and not all of them are strictly associated with the aquatic environment. Some are even capable of making sounds. Fiddler crabs (or fiddler crabs) live in the intertidal zone of tropical seas. They can stay on land for a long time. They have nothing to whistle with (they need lungs to whistle), and crabs, although they crawl onto land, breathe not with their lungs, but with their gills. But they learned to communicate using sound. Hitting the ground with their claws, they knock, thereby notifying their fellows of approaching danger. Click crayfish live in shallow sea waters. They can make clicking sounds with their claws. But it's not just a knock. When a crayfish hits a “moving” finger of its claw against a stationary one, an effect called cavitation occurs: a sharp drop in pressure in the liquid causes gas bubbles to form, which is accompanied by an explosive sound. Many species of lobsters (these are large sea crayfish without claws) are capable of producing crackling and grinding noises. But they produce sounds differently - as if they were playing a string instrument. On the antennae of lobsters, at the very base, there is a comb used as a bow, which the crayfish moves with great frequency across the outgrowth on the head - the “file”. The pitch and volume of the sound can vary depending on how hard you press the bow. It is not known exactly who all this “music” is intended for. Most likely, lobsters scare away predators in this way, because most often they make sounds at the moment of fright. It has not been proven, but it is not excluded that this is how they communicate with their relatives.When the saying about whistling cancer appeared, the last word was written with a capital letter. Cancer is the nickname of the famous Odessa marviher (as touring thieves were once called) Rakachinsky, given to him not so much because of his surname as because of a special feature - his strongly bulging eyes. Once Cancer lost a bet, according to which he was obliged to whistle three times on a bypass road (Škodova Gora) during its intensive use. Since rains flooded Peresyp extremely rarely, this circumstance gave rise to the famous phrase).
Answer the questions posed after the group discussion.
Task No. 2 (“General characteristics of arthropods”)
Give answers to the questions asked. Write the answer in the form of a crossword puzzle according to the diagram (on the board). Answers (words) can also be in adjective form; there can be several answers to one question
Questions for the crossword:
A fly, a crayfish, a spider belong to the type…. (keyword write from top to bottom)
symmetry of cancer body...
Cancer has a body cavity...
name of classes of the type being studied...
animals of this type originated from ..... worms.
The body of animals is……..e.
limbs of this type..., hence the name of the type itself.
The body cover consists of...
Task No. 3 “The internal structure of a crayfish” Card “revive the crayfish”
Collect the organs and organ systems of crayfish in the correct order and the crayfish will “come to life”!
Organs in the form of separate parts.
Task No. 4 “External structure of crayfish” draw up a table prepared in advance on the board
Cancer body parts
Structural features
Meaning(optional question)
Veils
chitin
Body parts (number and name)
Two, cephalothorax and abdomen
Eyes (number of simple or complex, location)
1 pair of complex ones, on the front of the cephalothorax
Antennae (number and location)
2 pairs, short (olfaction), long (touch), on the cephalothorax
Number of walking legs
5 pairs
Number of abdominal legs
4-5 pairs
Draw a conclusion about the adaptability of crayfish to its habitat.
Physical exercise in class
To warm up the cervical vertebrae “Turtle” - without lifting the body from the chair, “press” the shoulder girdle towards the floor, and try to reach the ceiling with your head (movement of the turtle’s head).
An exercise for developing correct posture (used without fail by cadets of the Kremlin troops) is “throwing your jacket on the floor,” i.e. we must imagine that our shoulder girdle is a jacket and it must be thrown off in one movement to the floor.
Exercise for hands - drawing a figure eight in the air with one hand, then with the other, and then simultaneously, with both hands, drawing a figure eight in the air.
Additional material
The meaning of crustaceans
Daphnia, cyclops and other small crustaceans consume large amounts of organic remains of dead small animals, bacteria and algae, thereby purifying the water. In turn, they represent an important source of food for larger invertebrate animals and juvenile fish, as well as for some valuable planktivorous fish (for example, whitefish). In pond fish farms and fish hatcheries, crustaceans are specially bred in large pools, where favorable conditions are created for their continuous reproduction. Daphnia and other crustaceans are fed to juvenile sturgeon, stellate sturgeon and other fish.
Many crustaceans are of commercial importance. About 70% of the world's crustacean fishery consists of shrimp, and they are also bred in ponds created in the coastal lowlands and connected to the sea by a canal. Shrimp in ponds are fed with rice bran. There is a fishery for krill - planktonic marine crustaceans that form large aggregations and serve as food for whales, pinnipeds and fish. Food pastes, fat, and feed meal are obtained from krill. The fishing for lobsters and crabs is of less importance. In our country, Kamchatka crab is harvested in the waters of the Bering, Okhotsk and Japan seas. Commercial fishing for crayfish is carried out in fresh water bodies, mainly in Ukraine.
Bionics and crustaceans
Chitin is a building material of insects and crustaceans
Insects, spiders and crayfish create their shells from chitin. This natural substance may also be useful for humans. Lots of features. Chitin is a multifunctional material that can be used for various purposes by modifying it accordingly. The framework of chitin molecules, for example, may contain other substances that make chitin harder. This is exactly what can be observed in the stings of bees and wasps, which, without bending or breaking, must penetrate into tissues, or in the thin but hard parts of the joints of the wings of flies and bees, which can withstand heavy loads. Used in other sequences, chitin can be very soft. This is used, for example, by arthropods - in the articular skin between the plates or tubes of the chitin shell. Only thanks to this, the plates can move, while harmful substances do not penetrate into the insect’s body between the individual plates. And finally, calcareous material can be mixed into the chitin, thereby imparting rigidity to the shell. Crustaceans use this opportunity to protect themselves from enemies. Material of the future. Chitin is a growing material. It can be obtained, among other things, from the shells of North Sea crabs and then refined using various chemical processes. Chitin could be an important material of the future, with many applications. This material is especially important in medicine and pharmaceuticals, since the human body does not perceive chitin as a foreign body and therefore does not reject it. By applying chitin, for example, the treatment of burns can be significantly improved.
What is the importance of crayfish in nature and human life you will learn from this article.
What are crustaceans?
Crustaceans are a diverse and numerous group of primarily arthropods that live in aquatic environments. These include about 40,000 modern species of crustaceans. Some of them are bottom-living, while others are an integral part of freshwater and marine plankton. These are, as a rule, mainly active crawling or swimming animals. But among such crustaceans you can also find immobile attached forms - such as sea acorns and ducks. Some of the crustaceans have adapted to life on earth. For example, woodlice can live in the soil of various latitudes, even in the desert, but at the same time they lead a rather hidden lifestyle and live in burrows
The importance of crustaceans in nature and human life
The importance of crustaceans in human life cannot be exaggerated - freshwater and marine species of crustaceans provide food for most species of fish and other animals. Daphnia and other crustaceans serve as food for various freshwater fish and their larvae.
Some types of crustaceans are able to strain water with their thoracic limbs during feeding. As a result, water quality improves. They eat dead organisms and this prevents the decomposition of organic matter in the water and its blooming.
People use crabs or lobsters as food, fried or boiled. They have a beneficial effect on the body. The beneficial substances contained in crustaceans improve vision and normalize the functioning of the nervous system. Their use reduces the risk of malignant tumors. Crustaceans are a source of vitamins, iron, calcium and zinc.
Woodlice, living on land, are capable of processing plant material, thereby enriching the soil and increasing its fertility.
We hope that from this article you learned what role crustaceans play in human life.
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.