Metazoans. Invertebrates. Animal Kingdom. Fauna.

This suborder includes all multicellular animals. The set of cells can be organized into more or less complex tissues. The life of all individuals originates from a single cell, which by successive divisions gives rise to the remaining ones that will form the organism, then differentiating into the various tissues and forming the corresponding organs.

It is difficult to establish the origin of the Metazoans. It is admitted that the first animal organisms evolved to form the Protozoa, separating these into several branches, mainly that of the Flagellates and the Poriferos. From the common line, forms with added cells emerged that ended up constituting multicellular organisms. However, they did not form tissues so they remained at the level of Mesozoans. The next step was the organization of these cells in real tissues, appearing the Coelenterates. These animals are called diblastic because their body is made up of two unique cell layers, an outer (ectoderm) and an inner (endoderm). With the appearance of a third intermediate cell layer (mesoderm), the rest of the Metazoa appear, which are called triblastics.

In the embryonic development of triblastics, a simple digestive tube is first formed with two openings: a mouth and an anus. Later, to give the adult individual, in some this disposition is maintained, while in others the mouth appears in a different place. In this way, two main lines of Metazoans are distinguished: the Prostostomes (where the embryonic mouth, the blastópore, is still preserved in the adult) and Deuterostomes (the blastopore closes and the adult mouth appears in a different place).

Protostomes comprise, among others, three large groups: Annelids, Mollusks and Arthropods, while Other important groups are included in the Deuterostomes: Echinoderms and Chordates .



Other information about fauna in Aragón:

A small list of species in Aragon would be the following:

Vertebrates	Invertebrates
Mammals Red squirrel. Bear. Fox. Artiodactyl Ungulates Deer. Wild pig. Birds Classification of Birds Storks. Capercaillies. Reptiles Amphibians Urodelos.    Marbled Triton.    Webbed Triton.    Pyrenean triton. Anurans. Fishes	Metazoans Arthropods Myriapods Insects Arachnids Spiders Crustaceans Annelids Worm Molluscs Asquelmintos Platelmintos Celentereos Porifera Protozoa
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.