Sponges- Porifera “Pore Bearer” Show examples Evolutionary sideline - alone. Simple multicellular animals lacking true tissues or organs. Sponges evolve from colonial flagellated protists Benthic and sessile as adults. Height ranges from 1cm. - 2m. Water drawn in through pores in body and expelled out osculum. Flagella create current.
Filter feeders, they can filter 100 liters of seawater an hour. Choanocytes (collar cell) phagocytize food on inside (flagellated cell) Amoebocytes digest and carry nutrients from choanocytes to epidermal cells. Amoebocytes also form skeletal fibers - spicules (CaCO3 or silica) or spongin (protein). Sexual Reproduction - hermaphrodites with cross fertilization. Flagellated larvas swim and find hard substrate. Planktonic in early stages.