Bio Lab Wksht & HW Questions 36

Bio Lab Wksht & HW Questions 36 - 31 BILATERIA. Animals...

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31 BILATERIA. Animals show primary bilateral symmetry . Organs are well developed and "organized" into systems . A body cavity ( coelom ) between the gut and body wall may be absent ( acoelomate ), partly lined with mesoderm ( pseudocoelomate ), or completely lined with mesoderm ( eucoelomate ). The type of coelom was previously thought to be important to understanding the phylogeny of the Bilateria (see Fig. 32.10 p. 634, Campbell and Reece 2005), but recent evidence suggests a different relationship among the phyla in the Bilateria (see Fig. 32.11, p. 635, Campbell and Reece 2005). Under current thinking, there are two main subgroups in the Bilateria, the Protostomia and the Deuterostomia . PROTOSTOMIA: The animals in this branch display a characteristic embryology with spiral, determinate cleavage, mesoderm arising from cells near the lip of the blastopore, coelom arising as a split in an originally solid mass of mesoderm, and mouth arising from the embryonic blastopore. (See Fig. 32.9, p. 632, Campbell
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This note was uploaded on 12/27/2011 for the course BSC 1020 taught by Professor Danmoon during the Fall '11 term at UNF.

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