Triploblasts [ unknown term ] (three-layer animals, lat. Triploblastica ) - multicellular organisms that in their embryonic development after the blastula stage go through the stage of three germ layers : the outer - ectoderm , the inner - endoderm and the middle - mesoderm . Germ layers arise during gastrulation .
Animals that are characterized by embryogenesis of this type (all higher animals , starting with flatworms ) develop into bilateral (bilaterally symmetrical) organisms. More simply arranged organisms, such as strewing ( jellyfish , coral polyps , hydras ), belong to two-layer ones . Even more primitive - sponges (Porifera), generally do not have tissue organization .
See also
- Diploblasts
Literature
- Sverdlov E. D. A look at life through the window of the genome: in 3 volumes. - T. 1: Essays on structural molecular genetics. - M .: Nauka, 2009 .-- 525 p. - ISBN 978-5-02-034331-3 .