Fish are animals or not: arguments for lessons in elementary school. What kind of animals are fish belong to?

Saying the word "animal", we first imagine an animal with a soft fluffy wool. But the world of animals is much more diverse, and is not limited to four -haired representatives.

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All living things that surround a person are animals: everything that crawls on the ground soars in the air and swims in a pond. Thus, fish, from huge 10 meter sharks to small aquarium guppies, are representatives of animals.

General characteristic of fish

The habitat of fish is water. Nature created their bodies streamlined, provided with a tail and fins, and all this in order to freely move in water. In the same place, in the water, the process of breathing, in which the gills are involved. The gills, like light ground animals, help hold oxygen and respiration.
If the body of the animals that we call animals is covered with wool, then the fish cover is a overflowing sparkling scales that continues to grow throughout life.
For some fish, a natural habitat is fresh rivers or lakes. Among them we are best known karas and pikes, catfish and bream. In the salt water of the seas and oceans, whales and sharks, pink salmon and flounders live.

What kind of animals are fish belong to?

We have already found out that fish are animals. In total, there are six groups of animals, one of which is called “fish”. In addition to fish, animals are also considered birds, reptiles, amphibians, invertebrates and, of course, mammals.
Fish relate to vertebratessince in the body of each of them there is a chord, which acts as a spine. Among the fish there are bone (for example, salmon or tuna) and cartilage (bright representatives are called slopes or sharks).

On what signs do they determine that the fish is an animal?

The common features for animals that distinguish them from plants are the following:

The cellular structure, the presence of several interconnected systems in the body: nervous, digestive, respiratory, etc.
Independent nutrition - ready -made organic substances are used in food.
The process of breathing and, unlike plants, the impossibility of photosynthesis.
Development and growth, for which the ability to move and move in space are characteristic.
The ability to reproduce. Moreover, the fish reproduction has precisely the reproduction.

Since the fish has absolutely all of the above signs, it is attributed to animals.

What is the difference between fish and other animals?

For all the similarity of the characteristic features of fish, there are significant differences that distinguish them in a separate group.
The unique differences in fish are the presence of fins and gills with which these animals can only be in water. It is the combination of these three differences (gills, fins, life in water) is characteristic only for fish.

An important difference is the presence of fins and gills

Are all water inhabitants fish?

Not all the inhabitants of the water depths are a group of fish. So, for example, kit, although he cannot live on land, but only in water, is a beast, since he feeds his children with milk, like mammals. In addition, he does not throw caviar, like fish, but produces living cubs. The same applies to dolphins.
But the shark is a fish that has gills and spineLike the same catfish or slopes. Or, for example, an octopus constantly living in the depths of the waters, karakatitsa or squid is not fish, but mollusks, because they have a leg or tentacle, as well as a rainbow (the so -called organ, which mollusks scrap and chopped food).
As you can see, not everyone who lives in the ocean, sea, river or pond are fish, although they are all animals.

Interesting facts about fish

Fish, like any animal, has a brain and therefore, contrary to common opinion, is able to experience pain.
Neurons in the brain of fish are actively responding to pressure changes and water temperature, to pollution.
The body of fish is able to meet the development of natural opioids (or simply - painkillers) to the resulting stimulus or injury.
If any of the stimuli manifests itself quite often, the fish is able to remember it and change its behavior, avoiding a repetition of unpleasant sensations.