Features, brief description and groups of aquatic animals. Breathing of aquatic animals How aquatic organisms breathe

An animal that lives in water for a certain amount of time or its entire life. Many insects, such as mosquitoes, mayflies, dragonflies and caddisflies, begin their life cycle, as aquatic larvae before developing into winged adults. Aquatic animals can breathe air or obtain oxygen dissolved in water with the help of specialized bodies called gills, or directly through the skin. natural conditions and that live in them can be divided into two main categories: water or.

Aquatic Animal Groups

Most people only think of fish when asked about aquatic animals. However, there are other groups of animals living in the water:

• mammals such as (whales), sirens (dugongs, manatees) and pinnipeds (true seals, eared seals and walruses). The concept of "aquatic mammal" is also applied to animals with, such as river otter or beavers, leading a semi-aquatic lifestyle;
• shellfish (eg sea snails, oysters);
• (for example, corals);
• (e.g. crabs, shrimp).

The term "aquatic" can be applied to animals that live as in fresh water(freshwater animals) and in salt water (marine animals). However, the concept marine organisms most commonly used for animals living in sea ​​water i.e. in the oceans and seas.

Aquatic life (especially freshwater animals) is often of particular concern to conservationists due to their fragility. They are exposed to overfishing, poaching, and pollution.

frog tadpoles

Most are characterized by an aquatic larval stage, for example, tadpoles in frogs, but adults lead a terrestrial lifestyle near water bodies. Some fish, such as arapaima and walking catfish, also need to breathe air to survive in oxygen-poor water.

Do you know why the hero of the famous cartoon "SpongeBob Square Pants"(or" Spongebob Square Pants"), depicted as a sponge? Because there are aquatic animals called marine. However, sea sponges do not look like a square kitchen sponge, like a cartoon character, but have a more rounded body shape.

Fish and Mammals

School of fish near the coral reef

Did you know that there are more species of fish than there are amphibians, birds, mammals and reptiles combined? Fish are aquatic animals because they spend their entire life in water. Fish are cold-blooded and have gills that take oxygen from the water to breathe. In addition, fish are vertebrates. Most fish species can live in either fresh water or sea water, but some fish, such as salmon, live in both environments.

Dugong - an aquatic mammal from the order of sirens

While fish live only in water, mammals can be found on land and in water. All mammals are vertebrates; have lungs; they are warm-blooded and give birth to live young instead of laying eggs. However aquatic mammals depend on water to survive. Some mammals, such as whales and dolphins, only live in water. Others, such as beavers, are semi-aquatic. Aquatic mammals have lungs but no gills and are unable to breathe underwater. They need to float to the surface at regular intervals to breathe air. If you've ever seen what a fountain of water looks like coming out of a whale's blowhole, you should know that it's an exhalation followed by an inhalation before the animal plunges back under the water.

Mollusks, cnidarians, crustaceans

Giant tridacna - the largest representative of bivalve molluscs

Mollusks are invertebrates that have soft muscular bodies without legs. For this reason, many clams have a hard shell to protect their vulnerable body from predators. Sea snails and oysters are examples of shellfish. Squids are also mollusks, but they do not have shells.

swarm of jellyfish

What do jellyfish, sea anemones and corals have in common? All of them belong to cnidarians - a group of aquatic, which are invertebrates, have a special mouth and stinging cells. The stinging cells around the mouth are used to catch food. Jellyfish can move around to catch their prey, but sea anemones and corals are attached to rocks and wait for food to come close to them.

red crab

Crustaceans are aquatic invertebrates with a hard, chitinous outer shell (exoskeleton). Some examples include crabs, lobsters, shrimp and crayfish. Crustaceans have two pairs of antennae (antennae) that help them receive information about their environment. Most crustaceans feed on the floating remains of dead plants and animals.

Conclusion

Aquatic animals live in water and depend on it for survival. There are various groups of aquatic animals, including fish, mammals, molluscs, cnidarians, and crustaceans. They live either in freshwater bodies of water (streams, rivers, lakes and ponds) or in salt water (seas, oceans, etc.), and can be both vertebrates and invertebrates.

Aquatic organisms breathe oxygen dissolved in water, with the exception of secondary aquatic animals, which in most cases have retained the air way of breathing.

Some organisms breathe with the entire surface of the body (skin respiration), others with the help of special outgrowths called blood and tracheal gills.

Cutaneous respiration occurs in a large number aquatic animals, which include protozoa, coelenterates, sponges, some worms (ciliary and oligochaete worms), some crustaceans (copepods), some mollusks (part of nudibranch mollusks, pteropods) and some representatives of other groups. In some branched crayfish (Rolyphmidae and Leptodora), the so-called head shield serves for breathing, which differs in structure from the rest of the integument and stains well when applied in vivo coloring.

Blood gills look like thin-walled outgrowths, inside which there is a highly branched capillary network of blood vessels or blood plasma. The blood gills of aquatic organisms, in contrast to the respiratory organs of terrestrial animals, are external outgrowths adapted to receive oxygen from the surrounding water; they can be located on different parts of the body. Polychaete worms, most crustaceans and mollusks, aquatic larvae of some insects, echinoderms, ascidians and fish have blood gills.

Tracheal gills, characteristic of aquatic larvae of a large number of insects from the orders of mayflies, dragonflies, stoneflies, large-winged, caddis flies and Diptera, have the form of thin-walled simple or branching outgrowths located on various parts of the body and containing thin tracheal trunks or a highly branching network of tracheal capillaries. Inside the tracheal gills is gaseous oxygen diffusing from the surrounding water through the thin covers of the gills.

Almost everything is secondary aquatic organisms they breathe atmospheric air, with the exception of insect larvae that have fucking gills or have switched to skin respiration. Mammals periodically rise to the surface of the water to ventilate their respiratory organs, as do aquatic insects—beetles and bugs, as well as aquatic larvae of many dipterous insects.

More interesting articles

Breathing of aquatic animals

Respiration is the process of absorbing oxygen (O 2) from the environment and releasing carbon dioxide (CO 2). There are the following types of water breathing:

- gas exchange through the entire surface of the body - sponges, bryozoans, leeches, roundworms;

- gill (gills - organs with a protruding respiratory surface and a dense network of blood vessels, oxygen from the water enters the blood through thin integuments and walls of blood vessels) - frog tadpoles, newt larvae, gill mollusks, crayfish;

- tracheal (trachea - a system of air tubes penetrating all tissues of insects; oxygen from the water penetrates through a thin cuticle, then into the trachea and is delivered through them to all tissues of the body) - larvae of dragonflies, mayflies, caddisflies, folded flies.

Scheme of gas exchange in the gills (left) and trachea.

Internal gills (1) in the barley and external gills (2) in the crustacean branchipus, tadpole and newt larvae.

Various types of water tracheal respiration: 1) closed, without spiracles and additional protrusions, the tracheal system - many small insects: 2) with external additional gill sheets - mayfly larvae; 3) tracheal gills in the cavity of the rectum, gas exchange occurs when water is taken in and pushed out for jet propulsion - dragonfly larvae.

Air breathing:

- pulmonary (lungs - a cavity formed by a deepening of the respiratory surface, penetrated by capillaries). In pulmonary mollusks (pond, coil) - in the form of a simple sac-shaped depression, in adult frogs, newts - a more complex branched structure;

- tracheal - the trachea is filled with air when the surface film of water breaks through the spiracular tube at the posterior end of the body (mosquito larvae, water scorpion, silt fly larvae); in swimming beetles, the spiracles open into a closed space under the wings, where a supply of air is drawn in;

Varieties of air breathing: a swimming beetle gaining air; a pond snail crawling along the underside of the surface film of water with an open entrance to the respiratory cavity; a larva of a swimming beetle and a water scorpion, which exposed spiracular tubes; lion fly and mosquito fly larvae suspended from the surface film of water during respiration.

- diffusion gill - an air bubble on the abdomen, into which spiracles are open, as oxygen is consumed, additional oxygen from the water enters the bubble for some time due to the difference in gas pressures (smooth);

- plastron - part of the body surface covered with water-repellent hairs that hold air; hairs prevent air from contacting water, so the air layer does not decrease, and oxygen from the water penetrates into it unlimitedly for a long time(water bug, water lovers); plastron - part of the body surface covered with water-repellent hairs that hold air; hairs prevent air from contacting water, so the air layer does not decrease, and oxygen from the water penetrates into it for an unlimited time (water bug, water lovers);

- internal supply of oxygen - some water bugs have large cells with hemoglobin in the abdomen, which create a long-term supply of oxygen consumed under water.

author Taras Anatoly Efimovich

From the book Crossword Guide author Kolosova Svetlana

Aquatic champions 3 Web, Matthew - captain, England, swim across the English Channel. Xue, Han - China, 50 m, breaststroke, Germany, Gelsenkirchen. 4 Otto, Christine - GDR, swimmer: 6 Olympic awards. Spitz, Mark - USA, swimmer: 11 Olympic medals. 5 Popov, Alexander - Russia, swimming: 50,

From the book Oddities of Our Body - 2 by Juan Steven

The Water Monkey Theory This highly controversial theory states that humans came from aquatic environment and lost their hair for the same reason that whales, dolphins and manatees. It is the layer of subcutaneous fat that helps to keep warm in the water, and not the hair9. Needless to say, each of

From the book Fundamentals of Security traffic author Konoplyanko Vladimir

Overcoming water obstacles Fording a river begins first of all with a survey of the bottom, determining the depth, hardness of the soil, identifying holes and large stones. Signs of a ford can be: roads and paths approaching the river from both sides; local expansion of the river on its

From the book Inhabitants of the Reservoirs author Lasukov Roman Yurievich

Movements of aquatic animals Swimming: - with the help of fins at the rear end of the body - newts, larvae of dragonflies, mayflies, beetles; - with the help of wave-like movements of the body - worms; - with the help of limbs - water beetles and bugs, frogs; - with the help of a water shot - larvae

From the book Military Intelligence Survival Textbook [Combat Experience] author Ardashev Alexey Nikolaevich

Reproduction of aquatic animals - sexual reproduction, whose products are caviar in a gelatinous shell (newts, frogs, mollusks, caddisflies, mosquitoes-twitchers) or eggs of various shapes laid on various items and parts of plants both in water and out

From the book Basic Special Forces Training [Extreme Survival] author Ardashev Alexey Nikolaevich

Communities of aquatic animals Each species of animals chooses a suitable habitat (biotope, microstation) for life, to the conditions of which it is most adapted. It is possible to identify characteristic biotopes that are homogeneous in terms of factors, in which stable species are formed.

From the book Autonomous Survival in extreme conditions and autonomous medicine the author Molodan Igor From the author's book

From the author's book

3.7. Overcoming water barriers 3.7.1. Fording The main condition for crossing a river is the choice of a ford site. For a ford crossing, a place is chosen where the river is divided into several branches. You need to cross it in the widest place below the turn of the river or

From the author's book

Overcoming water barriers Wade crossing For the ford crossing, a place is chosen where the river is divided into several branches. You need to cross it in the widest place below the turn of the river or downstream with an island between the branches. The maximum fording depth in

The average human lung volume is 2500 milliliters. With a calm breath, 500 milliliters of air is absorbed, of which 140 remains in the so-called "harmful space", and 360 enters the lungs. This means that the alveolar air is ventilated by only one seventh (360/2500).

Aquatic mammals whales renew the contents of the lungs by 90 percent in one breath! Movable rib cage, powerful respiratory muscles, developed muscles in the lung tissue - all this is adapted to take a deep breath - push out the useless air that has given up oxygen and replace it as quickly as possible with a new portion of clean atmospheric air. With each respiratory movement, 4-5 times more oxygen enters the lungs of a whale than in the lungs of a person.

The sperm whale takes 60-70 breaths before a long dive; you can imagine how thoroughly he "charges" his body with oxygen.

In aquatic mammals, the so-called oxygen capacity of the blood is increased. It is known that oxygen is carried throughout the body by a special pigment contained in red blood cells (erythrocytes) - hemoglobin. Passing through the lungs, hemoglobin attaches oxygen and in the form of oxyhemoglobin rushes through the arteries to all corners of the body.

One gram of hemoglobin in human blood binds 1.23 cubic centimeters of oxygen, and seals - 1.78. To this it must be added that the process of oxygen binding by hemoglobin proceeds very rapidly in diving mammals.

Aquatic mammals are distinguished by the economical consumption of oxygen during diving. Thus, in a common seal, the oxygen consumption during one minute after immersion decreased by 15 times! This savings comes from different ways. The metabolism in the animal's body slows down, the amount of heat generated decreases, there are sharp changes in blood circulation and the nature of the blood supply to various tissues.

In a sea lion, for example, already 10 seconds after the start of diving, the number of heartbeats drops from 130-140 to 30-40 per minute, and in a gray whale - from 100 to 10 beats. But nutria is especially different in this respect. Her heart rate drops from 216 to 4 when submerged in water! The difference is colossal. In the northern elephant seal, the heart rate at the end of a 40-minute dive also dropped to 4, but the initial level in this species is much lower than in the coypu: 60 beats per minute.

Special measurements have shown that when diving, the blood pressure in the main vessels remains normal. But in small arteries, it decreases to the level of a venous one, and sometimes it completely disappears, that is, the pulse ceases to be felt.

The redistribution of blood flow has great importance for the beast. In any conditions, his brain is normally washed with blood, supplied with oxygen in abundance. The brain reacts painfully to a lack of oxygen: 4-5 minutes - and irreversible changes occur in delicate cells. "Revival" of the body becomes impossible. Other organs can also be on a starvation diet, they are much more enduring and unpretentious.

The nerve cells of the respiratory center of animals are located in the anterior third of the medulla oblongata. Aquatic mammals are very sensitive to the concentration of carbon dioxide in the blood. Slightly its content exceeds the norm - the respiratory center gives a "command" to increase the ventilation of the lungs, increase the flow of oxygen, improve the removal of carbon dioxide from the blood. And healthy body performs these commands, breathing becomes deep, the normal composition of blood gases is restored. But what is surprising is that the respiratory center of the brain of aquatic mammals is extremely resistant to an increase in the concentration of carbon dioxide in the blood.

On reflection, the scientists understood what the essence of the matter was: the preservation of these animals characteristic of land mammals sensitivity to carbon dioxide could allow the respiratory center to play bad joke with his master - to force him to increase the "ventilation" of the lungs at the most inopportune moment, while diving. Of course, a breath under water would be the last for the beast ...

Redistribution of the blood flow, increased nutrition of the brain when the animal is under water - these mechanisms are found not only in aquatic mammals - they are in the beaver, muskrat and some other animals.

Hemoglobin is not only in the blood, but also in the form of myoglobin is present in the muscle tissue of animals. Myoglobin stores oxygen and releases it as needed. Aquatic mammals have a lot of this pigment; dolphins, for example, have as much of it as hemoglobin. In the muscles of the heart and head of dolphins, myoglobin is 4-5 times more than in a rabbit or guinea pig, and in the dorsal and abdominal muscles - 15 times!

Scientists have found that the supply of oxygen in the human body averages 2640 milliliters, of which 900 in the lungs, 1160 in the blood, 245 in the tissue fluid, 335 milliliters in myoglobin - one seventh of general stock. In a seal, out of 5400 milliliters of oxygen, myoglobin retains over 2500, that is, almost half!

So, to get more fresh air, to make fuller use of the oxygen contained in it, to deliver it to tissues faster, it is better to “unload” it, to create reserves of air and oxygen when diving, to use precious gas more economically in a submerged state, to provide them primarily with vital centers - that’s what, in essence, all the most complex morphological and physiological adaptations developed in aquatic mammals in the process of the great return journey from land to water boil down to.

Some aquatic mammals have reached high degree perfection, while others have less bright and complete adaptations, but the principle is common to all. And this is the main thing for us.

Primitive gills are in. In most higher animals, these are located on the lateral walls of the body and the upper parts of the pectoral legs. Aquatic insect larvae have tracheal gills, which are thin-walled outgrowths on different parts bodies in which there is a network of tracheae.

Echinoderms have gills sea ​​stars and sea ​​urchins. All primary aquatic chordates (fish) have rows of paired openings (gill slits) located in the pharynx. In enteric-breathing (mobile bottom animals), tunicates (small marine animals with a sac-like body covered with a shell) and non-cranial (a special group of invertebrate animals), gas exchange occurs during the passage of water through the gill slits.

How animals breathe with gills

The gills consist of leaflets (threads), inside them there is a network of blood vessels. The blood in them is separated from the external environment by a very thin skin, while creating the necessary conditions for the exchange between gases dissolved in water and blood. Gill slits in fish, they are separated by arcs, from which gill septa extend. In some bony and cartilaginous species, the petals of the gills are located on the outer side of the arches in two rows. Actively swimming fish have gills with a much larger surface area than sedentary aquatic animals.

In many invertebrates, young tadpoles, these respiratory organs are located on the outside of the body. In fish and higher crustaceans, they are hidden under protective devices. Often the gills are located in special body cavities, they can be covered with special folds of skin or leathery covers (opercula) to protect against damage.

The gills also perform the function of the circulatory system.

The movement of the operculum during breathing is carried out simultaneously with the movement (opening and closing) of the mouth. When breathing, the fish opens its mouth, draws in water and closes its mouth. Water acts on the respiratory organs, passes through them and goes out. Oxygen is absorbed by the capillaries of blood vessels located in the gills, and the used carbon dioxide escapes through them into the water.