Continuing with the study of animals, in this publication we will learn about fish.
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Fish are animals that live alone in water and cannot live without it.
All fish have head, trunk, tail and fins.
The body of most fish is covered with thin plates, scales. Fish scales grow all their life. A ring is added every year. By the amount of rings in the scales, you can determine the age of the fish.
The fins and tail help the fish to swim in the water. His body is covered with scales. And they have an aerodynamic shape of the body.
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Like all animals, fish breathe oxygen. But they inhale it not from the air, but from the water. For this, fish have special organs: gills. The fish collect water in their mouths, pass it through the gills and extract oxygen from it.
Ichthyology1 is a branch of zoology dedicated to the study of fish.
The fish are freshwater and marine.
Freshwater fish live in rivers, lakes and ponds. This is Crucian carp, perch, pike, tench, catfish.
Marine fish live in the seas and oceans. This is herring, shark, flounder, mackerel.
The largest marine fish are sharks, capable of reaching 10 meters and weighing 20 tons.
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All fish are cold-blooded or poikilothermic animals. Their body temperature is equal (or almost equal) to the temperature of the water in which they swim.
As a result of natural selection, a wide variety of adaptations to the living conditions in fish has emerged. This manifests itself in the shape of the body, the color, the characteristics of the internal structure.
The fish's body can have a variety of shapes: flat, spindle-shaped, swept. It depends on the conditions of its habitat.
Reproduction:
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Reproduction is variable depending on the type of fish, there are three classes: viviparous, oviparous and ovoviviparous.
Small fish emerge from the eggs that large fish throw into the water.
Activites:
1.How is the age of a fish determined?
2.What are the fins and tail of the fish for?
3.What are the largest marine fish?
4.How and where do the fish breathe?