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Explore the fascinating Phylum Porifera, home to around 8000 species of marine and freshwater animals with unique shapes and sizes. Learn about their physical characteristics, body shapes, feeding mechanisms, reproduction methods, and more!
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PHYLUM PORIFERA Yes! . . . These are animals!!
Phylum Porifera • 8000 species • Mainly marine . . . but about 100 freshwaterspecies • Sessile adult forms, sometimes benthic • Many different shapes and sizes
Physical Characteristics • Body resembles a sac perforated with many holes PORIFERA = “pore bearer” • Asymmetrical • Sometimes showing irregular shapes • No organs or true tissues present! • Cells show specialization .... different jobs for different kinds! • Cells form layers
Body Shape • Simple sponge • Hollow • Upright • Cylindrical
Body Shape • Complex sponges • many shapes • Complex body wall … • Inner foldings • Complex systems of canals and chambers
So, what are they made of?? • Outer layer • Thin, flat epidermal cells • Pierced with pores • Inner layer • Specialized cells called collar cells or choanocytes
Between the inner and outer cell layers • Jellylike material containing: • Amebocytes – digest food and transport nutrients, as well as secrete skeletal structures • Spicules – the skeletal fibers made from calcium carbonate or silica
NO MOUTH!! … how can they eat?!? • Each pore allows water to enter the spogocoel • Sponges can filter food from the water pumped through their pores • (this is why we call them filter-feeders … DUH!!!) • The water then passes out of the osculum, or the opening at the top
Water in . . . Water out • Water enters through incurrent pores • Collar cells create an inflowing current using their flagella • Water flows through the spongocoel and then the oscula
Little Fingers • Food particles are captured and ingested by collar cells lining the spongocoel • Amebocytes in the middle layer pick up partly digested food
Sponge Babies!! • Asexual reproduction • “budding” • Groups of cells divide (“buds”) and break off • Unfavorable conditions lead “buds” to become “gemmules” – buds enclosed by tough outer covering • Sexual reproduction • Collar cells turn into gametes • Sponges are HERMAPHRODITES!! • Sperm leave through osculum and are drawn in through pores in neighboring sponges • Zygote becomes a free-swimming larva and leaves the mother sponge through the osculum
Gemmules It doesn’t look much like a sponge . . . YET!!
But, what should I know about Poriferans … • They are the lest complex animals Simple, simple, simple!!! • They do not show a tissue / organ level of organization • They are filter – feeders • They are BOTH asexual and sexual reproducers
THE END!!! You know that I couldn’t leave out this guy . . . “Everyone’s favorite poriferan!!”