What is the meaning of Fish? Concept and Definition of Fish

Definition of fish

1. Concept of fish

«Do you call fish?»

He is called fish all vertebrate animals that are not members of the Group of tetrapods (land vertebrates with four legs type quiridio). The specialty of Zoology which deals specifically with fish called Ichthyology.

As it is typical of the first vertebrates, they are aquatic, and in contrast to what we observe in tetrapods, breathing occurs mainly by gills located in recesses of the pharynx. Locomotion is based on a hydrodynamic shape, with lateral body movements aided by limbs that are fins. The group is heterogeneous and includes forms as diverse as Lampreys, sharks and tunas, totaling about 30,000 species.
Evolution
The fish originated from other chordates towards the beginning of the Cambrian. Is not known for certain exactly where to set their origin; the most primitive group of fish, the agnates - which do not have JAWS - includes the Lampreys and Hagfish, (although it is not clear whether the latter should be considered vertebrates).

Classification

The fish group is paraphyletic, defined by the exclusion of a taxon (tetrapods) another major (vertebrates), and not by the possession of common derived characteristics. The vast majority of the species existing today belong to two groups (sometimes considered classes, sometimes superclasses): Chondrichthyes or cartilaginous fish, including sharks, rays and chimaeras, characterized by own externally visible Gill slits and a skeleton consisting only of cartilage; and the agnatha, with bony skeleton and gills protected by an operculum. Many morphological, anatomical and physiological differences distinguish both groups. Chondrichthyes are a group of vertebrate very primitive, but very successful evolutionarily, since sharks are ancient animals that have not changed much since its inception.


Terrestrial vertebrates (tetrapods) differed from Lungfish fish related to the Coelacanth or the dipnoos, and some of the earliest forms are halfway between our concept of fish and amphibian.

Fish and other aquatic organisms can be classified environmentally by its tolerance to different salinities in euryhaline or stenohaline, as well as other aspects of its adaptation.They are one of the most numerous of vertebrates.

2. Meaning of fish

1. Aquatic vertebrate, of Gill respiration, usually with fin-shaped limbs, suitable for locomotion and lift in the water. The skin, with rare exceptions, is protected by scales. Reproduction is oviparous in the majority of these animals.
2 Substance resinous, strong, lustrous, brittle and yellowish brown color, which is obtained by casting in water cold residue that leaves the turpentine to finish out the turpentine.
3. Slang expression (be fish) to refer undertake those blind some of doubtful success.

From the latin piscis.
However, the second definition is really interesting. This is the meaning to which we will refer today...

...The fish--a dark and viscous product-, which was formerly obtained by cooking of resinous wood, today is produced by distillation of resins

Used to protect ships and waterproof objects. At the dawn of the twenty-first century used for carbon fiber or graphite, to manufacture gaskets, washers, bearings etc.

So now come, ladies and gentlemen, we have the fish and have the fish, and as they have seen the article it is not exactly related to the sex of the friendly aquatic vertebrate...

3. What is fish

Fish is a term that comes from PISCES, a Latin word. Fish are aquatic animals that, thanks to gills, can breathe under water. It is usually oviparous beings (which lay eggs).
For example: "In the Caribbean had the opportunity to dive among fish of all colors", "in my childhood I had a fish as a pet: had the tank beside my bed", "Marcelo was all afternoon in the spring, but it failed to capture even a single fish".
Although there are multiple species of fish, it is possible to enumerate certain characteristics that are common to most of them. A fish, in this way, often have fins to move easily from way underwater, as well as have the body covered by scales that serve as protection to your skin.
It is possible to find fish in freshwater (as in rivers or lakes) and salt water (seas). There are fish that live in a natural environment, while others are bred in aquariums or ponds for various purposes (for display, marketing, etc.).
When the fish is taken out of the water and die, he named it as a fish. The fish is a very important for human food, since it gives a lot of nutrients. Fishing (the activity consisting in the wild fish), in fact, allows the livelihood of many people being held in coastal regions.
Note that there is the modality of sport fishing with return, which involves removing fish from the water, but only on a temporary basis, to then return them to their environment.