BIOL 1002 : Exam Three Bio
Document Summary
3 main types: no coelem, pseudocoelem (cavities aren"t fully-lined with tissue from mesoderm, true coelem- fully-lined cavity. Segmentation: allows for more complex movement, body components controlled by separate muscles. Advanced excretory system with kidney-like nephridia; also filters blood. Detritivores- eat dirt and pass it, aerating soil. Hydroskeleton- consisting of a fluid-filled cavity, coelem surrounded by muscles. Two types: polychaetes ocean; feathery gills exchange gases and filter for food, leeches carnivorous/parasitic, can be used as a medical device for reconstructive surgery. Reproduce sexually and asexually: most are hermaphroditic. Have clusters of nerve cells called ganglia and nerve chords. Ganglia concentrated in head (nerves: gives them ability to learn. Open circulatory system- includes vessels and a hemocoel (open cavity) [not cephalopods] Increase in ganglia lead to increase in senses (taste and sight: eyes rival ours in complexity. Largest animal phylum: 1 million species described, 9 million total. Exoskeleton- protection and agility, rigidity, and flexibility: earliest terrestrial animals, includes chitin.
