Fish are vertebrate animals of aquatic life of which there are about 20,000 known species.
Aragon has no sea, therefore the number of species, exclusively freshwater is much smaller.
fish swimming
They almost always have elongated shapes that allow them to easily move in the water.
The most common forms are: Fusiform (spindle form), flattened and cylindrical.
Your skeleton can be bony or cartilaginous.
General Characters
The common characters are:
- Variable temperature.
- Limbs transformed into fins.
- Skin covered with scales or dermal denticles.
- Gill breathing, whereby they absorb the dissolved oxygen in the water.
- Simple and complete circulation.
Reproduction is usually through external fertilization, although some species have a copulatory organ.
The senses of taste, smell, etc., usually have them on the skin.
Circulation
The circulation in fish is closed, simple (from the heart to the gills) and complete (without a mixture of venous and arterial blood).
Breathing
Breathing in fish is gill.
Water enters the oral cavity and passes through the gills, where it takes the dissolved oxygen in the water.
Large groups of fish
| Cyclostoms or Agnatos |
They are not true fish. They have no lower jaw. They have no vertebrae or bones of any kind. They only have a dorsal cord. |
|---|---|
| Elasmobranchs | Fish with cartilaginous skeleton. Skin covered by dermal denticles. They have no swim bladder. |
| Teleost | Fish with partial or fully ossified skeleton. With scales and swim bladder. This group includes most of the fish. |
The evolution of fish
The primitive Ostracoderms evolved from the Amphibian and developed until they reached the primitive Ichtyostega, the first vertebrate that came out of the water.
The other vertebrate groups evolved from these primitive amphibians.
From the first placoderm fish, vertebrates evolved in various branches that have given rise to current vertebrates.
Other information about fauna in Aragón:
A small list of species in Aragon would be the following:
| Vertebrates | Invertebrates |
|---|---|
MammalsBirdsReptilesAmphibiansFishes |
MetazoansProtozoa |
|
images about the fauna in Aragon. photographs on invertebrates. beneficial animals for agriculture. | |
Auch Aragon genießt eine vielfältige und abwechslungsreiche Natur, in der Pflanzen vorbeigehen, Tiere, Geologie oder Landschaften erreichen wir ein fantastisches Bestiarium, das in seinen Denkmälern lebt.
Die Informationen werden ohne einen Spaziergang durch die drei Provinzen nicht vollständig sein, mit Abschaltungen in einigen seiner spektakulären Landschaften wie Ordesa, der Moncayo, Monegros oder durch Widerspruch den Ebro.
Sie können sich auch den immateriellen widmen: von der Legendenzusammenstellung das gilt auch für das universelle Aragon.