BISC 121Lg Lecture Notes - Lecture 16: Trichinella Spiralis, Hirudin, Hox Gene
Document Summary
Annelids are aquatic, terrestrial, and parasitic: bodies are a series of fused rings, oligochaete- earthworms and their relatives. Reduced head: polychaeta- have many chaetae, hirdunae- leaches. Worms copulate and make cocoons that hatch worms. Polychaetes have paddle-like parapodia that help with movement and act as gills: (cid:862)christ(cid:373)as tree(cid:863) (cid:449)or(cid:373)s filter feeders, sessile (attached to a substrate) Leeches are blood sucking parasites: excrete hirudin which is an anticoagulant, appro(cid:448)ed for use (cid:271)y fda for (cid:862)lee(cid:272)h therapy(cid:863) for s(cid:449)elli(cid:374)g redu(cid:272)tio(cid:374) Nematodes are roundworms in most aquatic habitats: have a cuticle (tough exoskeleton, usually small, complete digestive tract, no circulatory system, decomposer, sexual reproduction and internal fertilization, thrashing motion caused by longitudinal muscles, caenorhabditis elegans- important biodevelopmental model. Has determinate structure, research is done on these: trichinella spiralis- human parasite that causes trichinosis. Arthropods have been very successful: trilobites (extinct, uniramia- centipedes, millipedes, insects, chelicerate- horseshoe crabs and arachnids, crustacea- crabs, crayfish, pillbugs, water fleas, copepods.
