Triploblastique

At the métazoaires, the triploblastic are animals whose embryo organizes into three embryonic layers during the Gastrulation. These three layers are the Ectoderme, the Endoderme and, characteristic of triploblastic, the Mésoderme. The triploblastiques ones gather the animals of which here the S most known:

Plathelminthes : towards dishes, like the “towards recluses” (example: Fasciola hepatica , the Liver fluke);

Némathelminthe S: towards rounds (example: Ascaris );

Mollusc S: animals with soft body (example: Snail, Oyster);

echinodermatous S: animals having a calcareous Exosquelette roughcast Pedicel S (example: sea urchin, Astérie, Sea cucumber);

Arthropod S: animals with Cuticule containing Chitin (example: Insect S, Arachnida S, Crustacean S, Myriapode S, Trilobitomorphe S);

Vertebrate S: animals with Endosquelette (example: Poisson S, Amphibian S, Reptile S, Bird X, Mammalian S).

Synapomorphies

Presence of Mésoderme.

bilateral Symmetry plane (at least at the embryonic state - of or name Bilateria -).

the synapses all are one-way.

Presence of a central nervous system.

the genes of the development of the homeotic family are organized in complexes.

Note: The character homologous or not with the Cœlome (mesodermic cavity) at the Deutérostomien S and the Protostomien S is not established. We will retain simply that the cœlome is not set up in the same way at the two groups, and that there exist phyla, mainly at the protostomiens, which are deprived by it: this does not plead in favor of the assumption of a single evolutionary origin of the cœlome between these two groups.

See too

Diploblastique

Random links: