Every self-respecting fisherman knows for sure that there is a huge variety in the world of fish. In their structure, these living creatures belong to the chordates, but the types of fish range from small to large, from sea to river, and so on. In this article we will talk about what fish are, where they live and what is characteristic of different species. We hope you find this information useful!
A little about fish
Fish are aquatic vertebrate jawed animals that breathe with gills. They can live in almost any body of water: in s alty and freshwater, starting with streams and ending with the oceans. As mentioned above, fish are of the chordate type, as they have an internal skeleton along the axis, the so-called chord.
Waterfowl species worldwide numbered over 34 million a few years ago. In science there is a special section devoted to the study of fish. It's called ichthyology.
Fish varieties
As you know, types of fish 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 of the chordate fish type are covered in skin and scales (except in the rarest cases). The skin is made up of two parts: the epidermis and the 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.
In bony fish, unlike others, there are various types of scales. The types of fish, more precisely, the belonging of the fish to one or another type, determine the features of the scaly coating. So, sturgeons have 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 rounded and serrated. The scales are arranged in such a way that the anterior plates overlap the posterior ones. Not so long ago, scientists found that due to the comb surface of the dentate scales, hydrodynamic properties increase in waterfowl.
Fish coloration has a huge range of colors, moreover, some colors are "warning", which allows the body to be safe when near a predator. Also, the colors can be pale, sandy, sandy. It all depends on the habitat, the characteristics of water bodies. What types of fish, their environment, such and coloration.
The musculoskeletal system of fish is its system of tissues and bones. It turns out that they previously had a third pair of gills, but then the organs evolved into jaws. Fish swim directly with the help of paired and unpaired fins. Moreover, thanks to their fins, they perform complexmaneuvers.
The fins of bony aquatic animals have bony rays, while those of primitive aquatic animals have cartilaginous rays. Most fish use their tail fin as their main engine. The spine in fish is formed due to individual unfused vertebrae. The process of swimming fish occurs due to the contraction of the muscles that are attached to the spine by tendons.
The musculature of fish has "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 avoid unfavorable places. Most chordate fish have a 2-chambered heart, a circle of blood circulation, and a closed circulatory system. Blood circulates through the gills and body tissues away from the heart.
Feeding in these living creatures is as follows: fish capture food by holding it with their teeth. Food from the mouth goes to the pharynx, then to the stomach, where it is processed by enzymes from gastric juice. Fish have a large selection of food. They can eat plankton, crumbs, worms, other fry, and some even large members of the class. But in general, fish are herbivores, predators and deritophages. What is most interesting, many are able to change their type of food, for example, at the beginning of life they eat earthworms and plankton, and in adulthood they 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 a high urea content, this pressure is regulated.
Conclusion
Thus, we can conclude that the types of fish are very diverse, and each of them is characterized by a different structure, size, nutrition, behavior. They are all different, and fishermen need to know everything about them before catching fish!
