ch. 33 parazoa Flashcards
invertebrates
animals that lack a backbone
- comprise more than 95% of known animal species
phylum of subkingdom parazoa
phylum porifera (sponges)
phylum porifera characteristics
- sponges
- lack tissues
- multicellular w/ several types of cells
- no symmetry
- adults sessile, larvae free swimming
how do sponges feed
filter feeds - capture food particles suspended in water that passes through their body
process of filter feeding in sponges
water drawn in through pores into cavity called spongocoel and out through opening called osculum
ostium
opening into a vessel or body cavity
osculum
main opening at aboral end of sponge
- Latin origin - mouth
porocytes
cells that create openings in the sponge
different types of cells in sponges
- choanocytes
- amoebocytes
choanocytes in sponges
flagellated collar cells that generate a water current through the sponge to ingest suspended food
layer between cell layers in sponge
gelatinous noncellular mesohyl layer
amoebocytes in sponges
totipotent stem cells found in mesohyl that aid in digestion and manufacture of skeletal fibers
- absorb food from choanocytes, digest it, and carry to other cells
- move by pseudopodia in mesohyl
choano
funnel
spicules
structural support; mesohyle
reproduction of sponges
sexual and asexual
