Phylum Porifera Flashcards

Phylum Porifera

• Considered simplest metazoans, characterized by loose cell aggregation and minimal tissue organization.
• Exhibit cellular level of organization, with a division of labor among cells.
• Lack organs and organ systems, as well as structures like a mouth or digestive tract.
• Not classified as diploblastic or triploblastic; feature rudimentary nervous integration.

Chief Characteristics of Sponges

• Defined by pores and canal systems facilitating water flow.
• Choanocytes, flagellated feeding cells, line cavities to create water currents.
• Possess an internal cavity known as the spongocoel, which opens to the outside via the osculum.
• Internal skeletons made of spicules or organic fibers like spongin.

Spongocoel

• Central cavity of the sponge that operates as a chamber for water circulation.

Osculum

• The opening at the terminal end of the sponge, functioning similarly to a mouth, allowing water to exit.

Spicules

• Microscopic skeletal elements made of calcium carbonate or silica, contributing to sponge structure and protection.

Choanocytes

• Specialized cells that line the interior cavities and are responsible for creating water currents, which aids in feeding and respiration.

Grantia

• A genus of calcareous marine sponges within the phylum Porifera.
• Colonial, benthic, and sessile filter feeders, typically asymmetrical in shape.
• Sometimes referred to as Scypha in older literature.

Structure of Grantia (Sycon)

• Specific structural adaptations that include a syconoid body plan, allowing for greater surface area and efficiency in water filtration.

Radial Canal

• Canals lined with flagellated cells, closed at one end and opening into the central cavity.
• Does not have direct connection to the external environment, serving as a passageway for water.

Incurrent Canals

• External spaces between enclosed canals, leading into the sponge while ending blindly at the inner end.

Dermal Ostium

• Minute openings on the sponge surface that provide access to the incurrent canals, facilitating water intake.

Spongin Fiber

• Type of collagen protein forming the fibrous skeleton of many sponges, secreted by spongioblasts.
• Provides flexibility and is characteristic of members in the class Demospongiae.

Glass Sponge

• Specialized sponges known for their silica spicules, distinguishing them from other sponge types.

Test your knowledge on Phylum Porifera with these flashcards. This quiz covers key characteristics of sponges including their cellular organization, division of labor, and lack of complex structures. Ideal for biology students looking to enhance their understanding of this fascinating phylum.