Invertebrate Notes
Sponges- Porifera “Pore Bearer”
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• 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.
• Asexual reproduction 1. Extensive regeneration
2. Fragmentation or budding