Zoology Chapter 4, Classification and Phylogeny of Animals

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ZoologyChapter 4, Classification and Phylogeny
of Animals

• BIOL 1413
• Saturday, September 4, 2004

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KPCOFGS

• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

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Branch A Mesozoa

• Characteristics of Mesozoa- 1)Bilaterally
  symmetrical. 2)Has no organs or tissues. 3)Body
  contains no internal cavity. 4)Body possesses no
  digestive tract (gut). 5)Body only two cell
  layers in most places. 6)Has no nervous system.
  7)Has some cells develop inside other cells.
  8)Reproduction quite complex involving both
  sexual and asexual aspects. 9)All are
  endoparasites on other marine invertebrates.

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Branch B Parazoa

• The Parazoa are an ancestral subkingdom of the
  animals, literally translated as 'beside the
  animals.' Parazoans differ from their
  choanoflagellate ancestors in that they are
  macroscopic and have differentiated cells, but
  unlike "true animals" (Metazoa), they do not have
  tissues. There are two phylum of parazoa
  porifera and placazoa.
• Porifera are the sponges.
• Parazoans are characterized by the lack of well
  defined tissues. There is only one species of
  placozoa and it is microscopic.