Why fish are the most adapted group of vertebrates to aquatic life

1. Adopt gills instead of lung breathing;

2. The body is streamlined, and it can move freely and rapidly in the water;

3. There are a variety of organs or structures suitable for aquatic life, such as swim bladders (which can regulate their own floating or sinking), fins (to maintain their own balance and rapid movement), transparent touches outside the eyes, scales, etc.

4. Reproduction needs to be carried out entirely in water, and the amount of reproduction is large, so as to maintain the requirements of racial continuity in the water environment.

1. Fish have gills and can breathe in water.

2. The body shape of the fish is streamlined, which can reduce resistance.

3. There is a swim bladder in the body of the fish, which can keep the fish in a water layer suitable for survival.

4. Fish have many differentiated fins that play different roles.

5. Fish have lateral lines, which can balance the osmotic pressure in the body and play a role in sensing the water flow.

6. Most of the back is dark, and the abdomen is light, which is a protective color.

7. Strong reproductive ability.

Fish have the characteristics of being suitable for living in water, and the color of the body of the fish is the protective color of the fish. The body is streamlined, large in the middle and small at the end. The surface of the body is covered with scales to protect the body, and there is a layer of mucus on the surface of the scales that reduces the resistance of the water when swimming.

There are swim bladders in the body.

The number of fish speciesThere are about 32,000 species of fish found in the world, and the fish live in the water, distributed in the ocean and freshwater, with two-thirds of the fish living in the ocean and the rest living in freshwater. There are about 2,500 species in China, and the differences between fish classes are as great as those between terrestrial vertebrates.

1. Respiration: gills are used to ingest oxygen in water; The structure of the swim bladder of some fish resembles a "lung" and can function as a breath respirator.

2. Exercise: The streamlined body reduces the resistance of water; The fins (pelvic, pector, dorsal, anal, caudal fin) help the fish move or balance in the book; In addition to protecting the body of the fish, the shield scales of cartilaginous fishes also serve to reduce the eddies formed by the currents flowing through the surface.

3. Sensation: The lateral line system of the body plays the role of sensing the flow of water and determining the direction; Lorenon can also sense the flow of water and determine the direction, and can sense the faint bioelectricity; The inner ear can sense balance and sound waves, and the Weberian apparatus of the order Cypriniformes is connected to the inner ear and can produce a hearing sensation similar to that of terrestrial vertebrates.

4. Buoyancy: Most bony fish have a swim bladder, which can be controlled by the absorption and discharge of gas in the swim bladder to achieve a certain degree of floating or diving, and sharks mainly rely on the liver that accounts for more than 20% of their body weight to adjust buoyancy.

5. Osmotic pressure regulation: The osmotic pressure in freshwater bony fish is higher than that of the external environment, so the osmotic pressure in the body is regulated by multiple urination and the reabsorption of salt in the filtrate by the renal tubules, so the renal bodies of freshwater fish are developed.

Characteristics of fish suitable for living in water: The body of the fish is fusiformal, and the body surface has a sticky and slippery feeling, which can reduce the resistance of the water; There are scales on the body surface that have a protective effect; The respiratory organs are the gills that absorb dissolved oxygen in the water Swimming with fins, etc. There is a lateral line in the body of the fish that can sense the flow of water, and the direction is determined to be the sensory organ of the fish

Multiple choice questions, one, two, three, four, five are all right, in order to adapt to life in the water, the body structure of fish has evolved into its current state, showing a streamlined body shape, breathing with gills, having a swim bladder, swimming with fins, etc.

The body structure of fish adapted to aquatic life has that scale. Plug also has the kind of streamlined body shape of his body. The use of the separation is thia, which can give him the effect of breathing. Then the scales are the functions such as waterproof pressing, and the streamlining body is what makes him faster.

The body structure of fish adapted to aquatic life is streamlined and suitable for swimming. In addition, there are fins on both sides of the body. Suitable for sliding while swimming.

Fish gills are used for breathing. Fish fat is used to move up and down. Fishtails are used to grasp directions. Therefore, the body structure of fish suitable for swimming in the water is the gills, tails and fat.

In order to adapt to life in the water, fish have gills that are responsible for breathing air, and in order to swim faster in the water, they basically have a body in the form of water droplets.

There are many kinds of body structures of fish adapted to aquatic life, such as fish breathe with gills, and the body shape of fish is streamlined, which is very suitable for swimming in water, so fish are very suitable for water life.

The body structure of fish adapted to aquatic life is characterized by a streamlined body structure, which can reduce resistance. , and the surface of the body is covered with scales. It is more comfortable to swim around, and the fins on the body can play a role in mediation. The role of the direction of velocity.

The body structure similar to amniotic fluid sex is due to its scales and plugs, which allow it to breathe in water. The body has a free curve and can swim freely.

The structure of the fish adapts to water life because the fish can breathe with its gills. Exhale the excess from the body. Nutrients absorb the nutrients needed by the fish in the water. There are also fish bodies covered with a layer of scales that protect the body of the fish.

There are too many body structures suitable for fish to survive in water, and all his structures are for survival in water. First there are fish floats that can float in the water. The gills filter nutrients from the water.

Yu Qi can swing the body in the water, the scales and streamlined body make the fish swim faster in the water.

The body structure of fish adapted to aquatic life includes: the body is streamlined outside, the body surface is covered with scales, the fins are used as locomotor organs, and the movement resistance in the water is small; gas exchange with gills; There is a line to sense the flow of water.

If a fish is able to adapt to aquatic life, the main body structure is due to its plug part that can expel excess water and some useless things, and then absorb some useful things.

Fish adapt to water life mainly they use the lungs. Gill respiration. They have no legs and no feet, so they have to live in the water, and it is an animal that comes down at will.

The body structure of the fish adapted to aquatic life, with its gills and floats, fins and tails, and so on.

The shape of the body of the fish itself is streamlined, suitable for swimming in the water, secondly, it has scales, which reduces the resistance of swimming, and he breathes with a sieve, these are the body structures of the fish suitable for aquatic life, and I hope to adopt them.

Fishes are vertebrates. It belongs to the vertebrate subphylum of the phylum Chordates and is generally divided into two groups, one is cartilaginous fishes and the other is bony fishes. Most of these animals live in water and can breathe with their gills while relying on their fins to swim, which also plays a role in maintaining balance.

Also, there are a few fish that can survive on land, but not for very long. <

Fishes are vertebrates. It belongs to the vertebrate subphylum of the phylum Chordates and is generally divided into two groups, one is cartilaginous fishes and the other is bony fishes. Most of these animals live in water and can breathe with their gills while relying on their fins to swim, which also plays a role in maintaining balance.

Also, there are a few fish that can survive on land, but not for very long.

1. Spindle shape: Spindle shape is the most common shape of fish, also known as the basic type, this body shape is most suitable for swimming, fast in the water, and can migrate long distances. Among the common food fish, carp and crucian carp are of this size, as is the shark, the most ferocious fish in the ocean.

2. Stick type: The stick type is also called the eel type, as the name suggests, it is the same body shape as the eel, and this body shape is mainly yellow eel and moray eel in addition to eels. It looks like a snake overall, and generally lives underwater, and its swimming ability is only spindle-shaped.

3. Side-flat type: The side-flat type looks like a sail, its left and right sides are very narrow, but the length and height are about the same. Fish of this size generally live in the middle and lower layers of the water column and are rarely able to perform long-distance activities. Common species are pomfret, swallowfish, butterflyfish, and many more.

4. Flat type: Flat fish can be regarded as the least good at swimming, and their movements are very slow and inflexible, such as stingrays, rays, etc. They look flat, and can only feed on small animals that live underwater.

Answer]: Fish have upper and lower jaws and paired appendages (even fins) that can or have large bites, and can actively feed. The bones are cartilage or hard bones.

The spine replaces the notochord as the body's main supporting structure. The skull is more complete, and the brain and sensory organs are more developed. Due to its adaptation to aquatic life, the body shape is mostly streamlined, the body is divided into a head, trunk and tail, the body is covered with bony scales or shield scales, and the body surface has a lateral line.

Adjust the specific gravity of the body with bladder or fat to obtain the buoyancy of water; Forward propulsion is obtained by the wave transmission of the segmented sarcomere of the trunk and the swing of the tail. The gills are used as respiratory organs. The blood circulation is single-circulation.

There is a good machine digging system that regulates the osmotic pressure in the body. Therefore, it belongs to the lower jawed vertebrates adapted to aquatic life.

Animals with vertebral columns composed of vertebral bones in the body belong to vertebrates, and animals without vertebral columns belong to invertebrates Vertebrates are divided into five classes according to the evolutionary order of structure from lower to higher, namely fish, amphibians, reptiles, birds, and mammals The largest group of vertebrates is the class of fishes, with about 22,000 species of fish, more than the number of other vertebrates combined; The second largest group of vertebrates is birds, with 9,021 species of birds in nature

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