tapeworm is triploblastic,what does it mean?how is hydra different from tapeworm in the aspect?Name the phylum to which hydra and tapeworm belongs?
The animals in which cells are arranged in two embryonic layers—an external ectoderm and an internal endoderm—are calleddiploblastic animals. In these animals, an undifferentiated mass of tissue called mesoglea fills the space between the ectoderm and the endoderm. Coelenterates are diploblastic animals.
The animals in which the developing embryo has three germinal layers, viz. the ectoderm, the mesoderm and the endoderm, are calledtriploblastic animals. Platyhelminths and all chordates are triploblastic animals.
The body of a coelenterate (or hydra) consists of two cell layers—the ectoderm (the outer layer) and the endoderm (the inner layer). Hence, it is a diploblastic animal. Whereas, the body of a platyhelminth ( or tapeworm) consists of not only the ectoderm and the endoderm but also the mesoderm (the layer of cells found between the outer and inner layers). Therefore, it is a triploblastic animal.
Hydra belongs to the phylum Coelentarata. Tapeworm belongs to the Phylum Platyhelminthes.
