The diversity of invertebrates (e.g. sponges, jellyfish, flatworms, molluscs, segmented worms, round worms, arthropods, echinoderms and several smaller phyla) is explored, focusing on taxonomic characters that define each group and their placement in the evolutionary tree of life, ecological function, biological requirements, and geographical distribution. Labs emphasize identification and recognition of major groups, including dissection when appropriate. (Lab Materials Fee: $26)