BIOL 111 Lecture 9: Lecture 9 Arthropods I

• School: McGill University
• Department: Biology
• Course: BIOL 111
• Professor: Andrew Hendry

Document Summary

Coelom -fluid filled body cavity lining developed from mesoderm (arthropods) A place for nutrient and oxygen exchange. A place where internal organs can move independently from each other. Pseudocoelom - fluid filled body cavity not developed from mesoderm (nematodes) Acoelomate - no body cavity, solid except digestive space. Organisms that grow by molting, shedding their exoskeleton, growing a new exoskeleton/ cuticle. Can live in sediment without oxygen, 1st organism found in this. Do not infect humans, only invertebrates, arthropods (thank god) Used by mcgill prof to study aging. Common all over world (mountain, marianas trench, arctic) Super tough indestructible , can survive in vacuum of space. Onychophorans (velvet worms) (looks like a caterpillar) Shoots 2 streams of paralyzing venom at prey. Caterpillars did not evolve from hybridogenesis with onychophorans. Place for muscle attachment (muscle can pull against) Opportunity for morphology not immediately exposed to environment. Requires a lot of energy to shed and make new shell.