BIOL 121 Lecture Notes - Lecture 21: Cuticle, Saprotrophic Nutrition, Motility
12 Apr 2015
School
Department
Course
Professor
Document Summary
Marine sandworm burrows into sand along shoreline. Leech local freshwater predator, modified mouth for sucking blood (suction cup to hold on, knife like structure to make a small cut, anticoagulant to keep blood flowing) Terrestrial in soil, sometimes down to a few meters. Chemoheterotrophic saprobe feeds on dead and decaying matter in soil. Cuticle protective covering, helps keep earthworm moist so earthworm can respire through skin. Setae bristles on ventral surface provide traction while moving. Segmentation allows effective use of circular and longitudinal muscles against coelom = powerful forward motion regions of the body. Hydrostatic skeleton fluid within coelom acts as a hydrostatic skeleton. & long. muscles contract in alternating waves and act against each other and the coelom, again segmentation helps this motion, setae anchor into soil (provide traction/grip) Hermaphroditic, sperm is swapped between two worms and stored until needed.
