PHYLUM PORIFERA Yes! . . . These are animals!!

Phylum Porifera 8000 species Mainly marine . . . but about 100 freshwater species 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 Inner 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

This gets the point across!

Sponge Babies!! Asexual reproduction Sexual 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

It doesn’t look much like a sponge . . . YET!! 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!!”