BI256 Lecture Notes - Lecture 11: Auxotrophy, Nacre, Nephridium
Document Summary
Mollusks part i chapter 16 bi256 animals jan. 27th. 90,000 living species most marine, some are terrestrial or freshwater aquatic. Soft body and belong to the lophotrochozoan protostomes. Size range: 1mm to 18m, but 80% are less than 10cm in size. Habitat range: 7000m above sea level to abyssal depths. Diet: herbivores, detritivores, filter feeders and predatory carnivores. Phylum includes: oyster, octopus, land snail, squid, scallops, sea slugs, cuttlefish. Simplest body plan consists of: foot or head-foot portion, visceral mass portion, shell. Mollusc body plan: head-foot and visceral mass portions. Head foot region contains feeding, cephalic sensory, and locomotor organs. Visceral mass contains digestive, circulatory, respiratory, and reproductive organs. Mantle cavity: two folds of skin form protective mantle or pallium, space between mantle and body wall is the mantle cavity. Mantle cavity houses the gills ( ) or lung in most molluscs: mantle secretes a shell over the visceral mass. Well-developed head bearing mouth and some sensory organs.
