Fish are a group of Vertebrate animals that have conquered almost all aquatic ecosystems on the planet. Thanks to their incredible diversity, they are found in sweet waters y salads, since the Deepest oceans until the mountain streams. Its classification is essential to understand its behavior, its characteristics anatomical and its adaptation to the environment.
General classification of fish
Fish are classified into several main groups based on their anatomy and evolution. The most widely accepted classification divides them into the following: three large groups:
- Bony fishes (Osteichthyes): They are the most numerous and have a bone skeleton.
- Cartilaginous fishes (Chondrichthyes): include Sharks, stripes y chimeras, with a cartilage skeleton.
- Cyclostome fishes (Agnatha): They are jawless fish that include the lampreys y hagfish.
Bony fishes (Osteichthyes)
The bony fish They constitute the most diverse group within the animal kingdom, representing more than 95% of all species de peces existing. They are characterized by:
- Un skeleton composed of bone instead of cartilage.
- Gills protected by a bony operculum.
- An swim bladder which allows them to control their buoyancy in the water.
- Fins supported by bone spines and membranous skin.
Within bony fish We find two main subgroups:
Actinopterygians
They are the fish with ray fins, the most common in aquariums and oceans. Examples include the and clownfish’s most emblematic landmarks, the goldfish and trout.
Sarcopterygian
Its lobe-finned fishand coelacanth and lungfish, which were key in the evolution of terrestrial vertebrates.
Cartilaginous fishes (Chondrichthyes)
This group is composed of species with a skeleton composed entirely of cartilage, which gives them a lighter and more flexible structure. Its features include:
- Lack of bony operculum, instead they have open gill slits.
- Skin covered with placoid scales, which gives them a rough texture.
- Replaceable teeth during all his life.
- Internal fertilization and, in some cases, viviparity.
Examples de peces cartilaginous
- White shark (Carcharodon carcharias): Predator of the oceans, essential for ecological balance.
- Manta ray (Manta birostris): Known for their large size and filter-feeding habits.
- Chimaera (Chimaera monstrosa): Deep-water cartilaginous fish with a primitive appearance.
Cyclostome fishes (Agnatha)
Are the most primitive fish and lack jaws. They are characterized by:
- Un elongated body resembling an eel.
- mouth with suction cup equipped with horny teeth.
- Lack of scales and real bones.
Examples de peces cyclostomes
- Sea lamprey (Petromyzon marinus): It feeds on the blood of other fish.
- Hagfish (Myxini): It secretes a viscous mucus as a defense.
Importance of fish classification
Understanding fish classification is crucial for biology and conservation, as it allows us to analyze their ecological functions, their relationship with ecosystems and their impact on food chains. marinas y fluvial.
As we progress in the study of fish, we discover that each species has unique adaptations to survive in the most varied aquatic environments, which demonstrates the impressive evolution of these vertebrates over millions of years.
