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Division of organisms: Symmetry- Radial Symmetry, this clade contains diploblastic organisms, those with only 2 germ layers, ( ecotoderm and endoderm). These organisms lack a true body cavity, and are called aceolomate.
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Division of organisms: Symmetry- Radial Symmetry, this clade contains diploblastic organisms, those with only 2 germ layers, (ecotoderm and endoderm). These organisms lack a true body cavity, and are called aceolomate. Bilaterial Organisms. This clade contains triploblastic organisms, those with 3 germ layers (ectoderm, mesoderm, and endoderm). Some bilaterial organisms are aceolomate, some pseudoceolomate, but most ceolomate with a true body cavity. Bilateral organisms demonstrate cephalization-development of a head. Most bilateral phyla are protostomes=mouth develops first.
Diploblastic Triploblastic
Body Plan A key transition in the evolution of the animal body plan was the evolution of the body cavity. The presence of a body cavity allows the expansion and lengthening of the digestive tract. An internal body cavity also provides space within which the gonads can expand. The evolution of efficient organ systems within the animal body depended upon the body cavity for supporting organs, distributing materials and fostering complex interactions. Three basic kinds of body plans are found in bilaterally symmetrical animals. Acoelomates: No body cavity (example: Platyhelminthes). Pseudocoelomates: Have a body cavity called the pseudocoel located between the mesoderm and endoderm (example: Nematoda). Coelomates: Fluid filled body cavity develops entirely within the mesoderm. This cavity is called a coelom. In coelomates the gut is suspended within the coelom which is surrounded by a layer of epithelial cells. This epithelial lining is called a peritoneum (ex: Annelida)
Class: Turbellaria Class: Trematoda Class: Cestoda http://www.youtube.com/user/torvaanser Phylum: Platyhelminthes Tapeworms in a bowl Land Planarian of Borneo Blue flatworm
Lance Nematodes – responsible for some corn disease Phylum: Nematoda
Filarial worms Ascaroid
http://www.youtube.com/watch?v=NNq6dKguwNU&feature=related monsters inside me http://www.cabrillo.edu/~jcarothers/lab/notes/parasites/index.html web site http://www.liveleak.com/view?i=807_1207540048 cat round worms Nematode in the Weep Video