Animals. Animal Kingdom. Wildlife. Fauna. Zoology.

A traditional classification to facilitate the study of animals is divided into Invertebrates and Vertebrates, the first without internal skeleton and the second with. However, they can also be classified according to the organizational level.

So we will then have the animal kingdom divided into two sub-regions: the Protozoa, with only cellular organization level, and the Metazoans, which are multicellular organisms.

The animal kingdom from greater to lesser complexity can be classified into the following groups:

            

PLURICELLULAR     or Metazoos
	BILATERALS
		CORDADOS	VERTEBRADOS With spine
			PROCESSED With dorsal cord	I N V E R T E B R A D O S
		CELOMADOS
			EQUINODERMOS With radial symmetry
			ARTROPODES With articulated appendages
			ANELIDOS Ringed worms
			MOLUSCOS Soft body with shell
		PSEUDOCELOMADOS	ASQUELMINTOS Roundworms
		ACCELOMATED	PLATELMINTOS Flat worms
	RADIALES	CELENTEREOS	An unperforated cavity
	PARAZOOS	PORIFEROS	SPONJAS A perforated cavity
UNICELULARES or Protozoa

Unicellular animals

In unicellular animals, their single cell has to perform all organic functions, although in some cases various parts of the cell are specialized.

Animal or vegetable?

Algae	Euglena	Protozoo
Vegetal	Vegetal- Animal	Animal

In unicellular organisms, it is sometimes difficult to differentiate plant or animal characters. Microscopic algae are considered as vegetables, but euglena has chlorophyll and eye spot. The same can be vegetable than animal.

Multicellular animals

In multicellular animals there are different cells that perform different functions.
The life of all metazoans originates from a single cell, which by successive divisions is giving rise to the remaining cells that will make up your body, then differentiating into tissues and forming organic organs and systems.

Porifers (sponges) and censorereos are the simplest animals, with only two cell layers.

The others have three cell layers from which various internal organs are formed.

Bilateral

Bilaterals are the next step among Metazoan animals, since they have a higher level of organization than just organic and have organ systems. A higher level of organization implies the appearance of a general body cavity completely upholstered by the mesoderm called celoma. According to the degree of complexity three groups can be distinguished:

1. Acelomados They lack celoma, like the Platelmintos.
2. Pseudocellomados They have a false celloma, like the Asquelmintos.
3. Celomados They carry celoma.

The procordates are a link between the invertebrates and the vertebrates.

Species extension:
Approximately two million species are known that are distributed very differently, as the arthropods comprise more than 90% of the known species.



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.

Also Aragon enjoys a diverse and varied Nature where passing by plants, animals, Geology, or landscapes we can arrive at a fantastic bestiary that lives in its monuments.

The information will not be complete without a stroll by its three provinces, with shutdown in some of its spectacular landscapes like Ordesa, the Moncayo, Monegros or by opposition the Ebro.

Also you can dedicarte to the intangible ones: from the legend compilation that also does to universal Aragon.