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The Group F Document Part 1. A Presentation of Invertebrates Ch. 32-35. By: Carl Eden Jimenez & Ryan Bierman, In C ooperation With: Davyn Leon & Roy Ezekeial Mandanas . he parazoa and Eumetazoa split into two about 940 million years ago.
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The Group F Document Part 1 A Presentation ofInvertebrates Ch. 32-35 By: Carl Eden Jimenez & Ryan Bierman, In Cooperation With: Davyn Leon & Roy Ezekeial Mandanas
he parazoa and Eumetazoa split into two about 940 million years ago. • Parazoa (near animals) have no bodily symmetry what so ever, and lack tissues. • Sponges are the only surviving species • Composed of animal kingdom except sponges and Mezozoa • Eumetazoa (true animal) are animals that have a definite shape and symmetry. The Parazoa & Eumetazoa
Pseudocoelomates Acoelomates • A pseudocoelom develops embryologically between mesoderm and endoderm. • Pseudocoelom means “false coelom” but is a true body space. • Characterized as a tube within a tube • Pseudocoelomates lack a circulatory system, and lacks the endothelial lining of a coelom • hydrostatic pressure gives the body a supportive framework • A coelom is a cavity that develops entirely within the mesoderm. • The coelom is surrounded by a layer of epithelial cells derived from the mesoderm and termed the peritoneum. • An acoelomate lacks a coelom & has bilateral symmetry and possess one internal space for the digestive track. Acoelomates & Pseudocoelomates
Sponge larva are free-swimming until they attach to a surface. • Sponges lack a head, appendages, mouth, anus, and organized internal structure. • Made of sever cell type and lack tissues. • Water passes through a flagellated chamber, it travels through channels that meet at a large opening called an osculum, through which water is expelled from the sponge. The Sponge
Radial symmetry- parts are arranged in a way that any longitudinal plane passing through the central axis divides the organism into halves. (pie) • Bilateral symmetry- both left and right sides are mirror images of each other. • Cephalization- a grouping of nerve cells into a brain, and sensory structures at the anterior end of the body. • Ectoderm- outer layer • Mesoderm- middle layer (m=middle) • Endoderm- inner layer • Archenteron- Primitive Gut • Protostomes- “first mouth” both mouth and anus form from the embryonic blastopore, or anus forms later. • Deuterstomes- “second mouth” the mouth does not develop from the blastopore, but in another pore that arises later. Blastopore make anus • Blastopore-The opening of an embryo's central cavity in the early stage of development • Segmentation- underlies the organization of body plans of most morphologically complex animals. Some Vocab