BIO 182 Exam 4 NAU QUESTIONS & ANSWERS RATED 100% CORRECT!!

1. Phylum Porifera - Answer-- sponges - loosely organized and lack tissues - multicellular with several types of cells - 8,000 species, mostly marine - no apparent symmetry - adults sessile, larvae free-swimming - water drawn through pores into spongocoel - flows out through osculum - choanocytes line spongocoel - mesohyl between choanocytes and epithelial cells - reproduce sexually and asexually 10. Phylum Nematoda - Answer-- roundwomrs - in nearly all habitats - over 20,000 species - tough collagen cuticle covers body - longitudinal but not circular muscles - pseudocoelom acts as hydrostatic skeleton and circulatory system - complete digestive tract, mouth with stylets - reproduction usually sexual with separate males and females - internal fertilization - large number are parasitic 11. Phylum Arthropoda - Answer-- perhaps most successful phylum - 3/4 of all decribed living species - success related to body plan that permits them to love in all major biomes- exoskeleton made of chitin and protein - segmented with appendages for locomotion, food handling, or reproduction - tagmata: fused body segments - extensive cephalization - sophisticated brain - open circulatory system - gas exchange - complete digestive system - excretion - subphylum chelicerata: spiders, scorpions, ticks and mites - subphylum myriapoda: millapedes and centipedes - subphylum hexapoda: wings and 35 orders, metamorphosis - subphylum crustacea: crabs, lobsters, barnacles and shrimp 12. Phylum Echinodermata - Answer--modified radial symmetry (5 parts) - cephalization absent - no brain - endoskeleton covered with spines -water vascular system - no excretory system (diffusion) - autotomy -reproduce sexually