Unformatted text preview: In examining zooplankton during an expedition to the Marshall Islands, you discover a new invertebrate species. This tiny creature has a lophophore, a crown of ciliated tentacles that helps it feed. This organism probably _____. has a spiral cleavage pattern during early development lacks mesodermal tissue has a blastopore during development that ultimately becomes an anus is a chromalveolate protist possesses cnidocytes on its tentacles Being sessile filter feeders, sponges have an asymmetric body plan characterized by numerous pores for water to enter. These pores are _____. regulated by Hox genes during development called ‘blastopores’, and are a crucial step in development created by cells termed ‘choanocytes’, cells that resemble the common ancestor of all animals lined with endodermal cells termed ‘oscula’, from the Latin for ‘mouth’ The extremely successful arthropod body plan is characterized by heterogeneous specialized segments; the arthropods were hypothesized to have acquired this adaptive body plan by shared derivation of two...
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This note was uploaded on 12/12/2010 for the course BISC 120 taught by Professor Webb,wetzer,? during the Fall '07 term at USC.
- Fall '07