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Unformatted text preview: spets favoring segmentation arising from convergent evolution. However, the genes controlling segmentation in each of these groups are the same, leading to a rethinking of the taxonomic value of segmentation. Sponges: The Phylum Porifera The phylum Porifera ("pore-bearing") consists of approximately 5,000 species of sponges. These asymmetrical animals have sac-like bodies that lack tissues, and are usually interpreted as representing the cellular level of evolution. Cells from fragmented sponges can reorganize/regenerate the sponge organism, something not possible with animals that have tissues. Most zoologists consider sponges as offshoots that represent an evolutionary dead-end., although others consider some groups of sponges as being related to other animal groups. Sponges are aquatic, largely marine, animals with a great diversity in size, shape, and color....
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This note was uploaded on 11/29/2011 for the course BIO BSC1010 taught by Professor Gwenhauner during the Fall '10 term at Broward College.
- Fall '10