BIO153H5 Chapter Notes -Radula, Cell Potency, Mesoglea
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32. 2) (i) cnidaria and ctenophora are traditionally considered diploblasts, but recent data indicate that some cnidarians have mesoderm. (fig. 32. 4a) (1) these animals are equally likely to encounter prey and other environmental stimuli from any direction: all other animals (i. e. , the triploblasts) have bilateral symmetry, a head region, and a central nervous system (cns) with ganglia. (fig. Freeman, biological science, 4e, chapter 32 (1) the few triploblasts that do not have a coelom are called acoelomates. (fig. 32. 5a) (2) those that do have a coelom are called coelomates. (fig. 32. 5b: the coelom serves as a hydrostatic skeleton that facilitates movement in animals that don"t have limbs. 32. 7a) (2) the coelom forms via splitting of blocks of mesoderm: deuterostome development (1) the anus forms first during gastrulation. (2) the coelom forms via mesoderm pinching off from the gut. (fig. 32. 8a: worms are a variety of different lineages that all have a simple tube-within-a-tube design. (fig.
