Author:
Qjure
Book:
Qjurious
Type:
Info
Chapter:
4-100.00.00
Parazoa
English: Parazoa means “near to animals”.
Zoology
Parazoa have symmetry in all directions. Their tissues are amorph. Their cells are unspecialized, and thus they have no organs.
Animal theory
Parazoa are identical to the sponges. In the Animal theory the protozoa, unicellular animals, are added to this phylum. They have in common with the sponges the lack of specialisation. They just exist.
Taxonomy
They are basal Metazoa, animals. Metazoa can be split in Porifera and Eumetazoa, the main of the animal kingdom. Euemetazoa asre also called Diploblasts, Epitheliozoa, or Histozoa.
Sponges were first to branch off the evolutionary tree from the common ancestor of all animals, making them the sister group of all other animals.
Classes
Calcarea
Hexactinellida
Demospongiae
Homoscleromorpha