Fishes

Fishes

Definition:

Fish (Pisces, from the Latin piscis = fish) are aquatic vertebrates with gill respiration. The class of fish does not describe a self-contained class, such as mammals, birds, amphibians or reptiles, but summarizes a group of morphologically similar animals.

Historically, the first fish appeared in the Ordovician about 480 million years ago. Today, biologists distinguish between 33,000 species of fish, and this number is constantly being revised upwards, as new species of fish are still being discovered.

In principle, two types of fish can be distinguished:

 Cartilaginous fish: skeleton of cartilage, e.g. Shark and rays

Bony fish: bone skeleton, e.g. Salmon and catfish

Note: Although the shape or habitat suggests, whale, penguin and dolphin are not fish.

Characteristics of the fish:

The class of fish combines some characteristic features, including e.g. the gill breathing, fins for locomotion and dandruff as protective armor. However, it may happen that isolated fish species do not have all the characteristics listed here. The reason for this is the long phylogenetic development, in the course of which z.T. developed very different manifestations.

* Fins: To move, fish use their fins.

* Reproduction: Most species of fish do not undergo copulation. Fertilization of the eggs takes place in the water.

* Smell: By far the best developed sense of fish is the sense of smell. Visually, fish only badly perceive their environment.

* Gill respiration: Fish absorb the oxygen released in the water via the gills.

* Spawning: Fish hatch from eggs, the so-called spawn. There are also live-bearing fish, but even with them the fish develop from eggs, but in the body of the fish.

* Poikilothermie: All fish are warm. Your body temperature is essentially determined by the outside temperature.

* Mucous glands: Below the scales are mucous glands. The secreted secretion protects against bacteria and reduces the frictional resistance in the water, so that fish can swim faster.

* Dandruff: The scale armor protects the fish from external mechanical effects.

* Swim bladder: All bony fish are in possession of a swim bladder. This allows fish to regulate the buoyancy in the water.

* Lateral Organ: The lateral line organ is a special sensory organ to sense movement. The corresponding sensory cells are located on the left and right side of the body.

* Vertebrates: As a vertebrate fish have a spine.

List of fish:

Eel, frogfish, brown trout, barbel, barracuda, blobfish, clownfish, cod, flounder, perch, trout, goldfish, guppy, shark, hammerhead, pike, cod, carp, dogfish, koi carp, puffer fish, salmon, mackerel, moderlieschen, Sunfish, Moray Eel, Piranha, Burbot, Coelacanth, Rainbow Trout, Ray, Redfish, Anchovy, Tench, Plaice, Swordfish, Seahorses, Turbot, Sturgeon, Tiger Shark, Tuna, Catfish, Pikeperch, Eel

Summary

Fish are aquatic vertebrates. Oxygen absorbs fish via the gills.

480 million years ago, the first fish appeared in the oceans.

About 33,000 known species of fish inhabit the seas and oceans. The actual number of species is likely to be much higher.