Questions and Answers
What does Calasea primarily consist of?
What are the defining features of Hexactinellida?
Spicules have 6 rays, spicules of silica, arranged as lattuce.
What type of spicules do Demospongiae have?
Spicules of silica or spongin.
Dascon is the simplest body form of sponge, characterized by the presence of ______ holes.
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What is the function of choanocytes in the Sycon class?
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What characterizes the Leucon body form?
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Study Notes
Classes of Phylum Porifera
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Calasea: Characterized by spicules made of calcium carbonate; exhibits asymmetrical or radial symmetry; spicules typically have 3 or 4 rays; can exhibit ascon, leucon, or sycon body forms.
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Hexactinellida: Known as "glass sponges", these spicules contain silica and have six rays; often found in deep sea environments; includes notable species like the Venus flower basket; arrange rays in a lattice structure; can form sycon or leucon body types.
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Demospongiae: Comprises brightly colored sponges with spicules made of silica or spongin; mostly represented in leucon body form; includes familiar species like bath sponges and freshwater spongilla.
Body Forms of Sponges
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Dascon: Represents the simplest and least common sponge body type; features astia holes for water entry; has a central cavity known as spongacoeli; water exits through osculum; lined with choanocytes on the inner surface of the spongacoeli.
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Sycon: Includes radial canals that are covered by an additional wall, enhancing surface area for filtration; contains more choanocytes for efficient water processing; maintains dermal pores analogous to astia; water flows into the spongacil and exits via the osculum.
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Leucon: Exhibits extensive branching, resulting in an increased number of choanocytes; water is drawn into chambers for filtration; water exits through osula; this form represents the majority of existing sponge species today.
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Test your knowledge on the various classes of Phylum Porifera with these flashcards. Each card provides definitions and characteristics of different classes such as Calasea, Hexactinellida, and Demospongiae. Perfect for biology students looking to reinforce their learning.
