Every self-respecting fisherman knows for sure that there is a huge variety in the fish world. By their structure, these living creatures are chordates, but the types of fish range from small to large, from marine to river and so on. In this article we will talk about what kind of fish are, where they live and what is characteristic of different species. We hope you find this information useful!
A bit about fish
Fish are aquatic vertebral maxillary animals that breathe through gills. They can live in almost any body of water: in salty and fresh, starting with streams and ending with oceans. As mentioned above, fish are of the chordate type, since they have an internal skeleton along the axis, the so-called chord.
Species of waterfowl all over the world several years ago amounted to more than 34 million. There is a special section in science dedicated to the study of fish. It is called ichthyology.
Species of fish
As you know, fish types are a huge section in ichthyology. Yes, of course, scientists spend a lot of time studying these animals. Fish are of the chordate type, as mentioned above, but each fish has its own characteristics.
Physiology and Anatomy of Fish
All creatures belonging to the type of chordate fish are covered with skin and scales (not counting the rarest cases). The skin consists of two generators: the epidermis and dermis. The epidermis produces a secret that allows the skin to be protected. The dermis, the inner skin layer, plays an important role in the formation of scales.
Bony fishes, unlike others, have various types of scales. Types of fish, more precisely, the belonging of a fish to one or another type, determine the features of a scaly coating. So, in sturgeons, ganoid scales. It is formed from bone plates coated with ganoin. The scales of bony fish living in our time are called elasmoid and are divided into round and serrated. The scales have a location that allows the front plates to overlap on the rear. Not so long ago, scientists found that due to the comb surface of the toothed scales in waterfowl, the properties of hydrodynamics increase.
Coloring fish has a huge range of colors, moreover, some colors are “warning”, which allows the body to be safe, being next to a predator. Also, the colors can be pale, sandy, sand. It all depends on the habitat, the characteristics of water bodies. What types of fish, their environment, such and color.
The musculoskeletal system of fish is its system of tissues and bones. It turns out that earlier they had a third pair of gills, but then the organs evolved in the jaw. Fish swim directly with the help of paired and unpaired fins. Moreover, thanks to the fins, they perform complex maneuvers.
The fins of bony aquatic animals have bone rays, while the primitive ones have cartilaginous rays. Most fish use the caudal fin as the main “engine”. The spine in fish is formed due to individual ungrown vertebrae. The swimming process of fish occurs due to the contraction of the muscles that are attached to the spine by the tendons.
The muscles of the fish have “slow” and “fast” muscles. They have a very developed sense of touch and smell, which helps them to navigate perfectly in the environment where they are and to avoid adverse places. Most chordate fish have a 2-chamber heart, a circle of blood circulation, a closed circulatory system. Blood circulates through the gills and body tissues from the heart.
The nourishment of these living things is as follows: fish capture food by holding it with their teeth. Food from the mouth follows the throat, then into the stomach, where it is processed by enzymes from the gastric juice. Fish have a large selection of food. They can eat plankton, crumbs, worms, other fry, and some even large representatives of the class. But in general, fish are herbivorous, predators and deritophages. What is most interesting, many are able to change their type of food, for example, at the beginning of life there are earthworms and plankton, and in adulthood eat small or large representatives of the aquatic environment.
Fish have problems with pressure, for example, their pressure may be lower than the pressure of the environment, but due to the fact that these living creatures have an increased urea content, this pressure is regulated.
