EEB266H1 Lecture Notes - Lecture 6: Parapodium, Pentastomida, Filter Feeder
28 Apr 2016
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Document Summary
Chaetoblast produces chaetes: bristle-like structure similar to setae. Metamerism or metameric growth serial repetition (multiplication) of body parts into segments (units) called metameres". Segmentation vs. strobilation: transverse septa completely isolate the coelomic fluid from adjacent unit. While only the terminal-most unit is completely isolated in stobilation prior to transverse fission. Telomeric segmentation: growth from the terminal (posterior) end. Polychaeta: parapodia with many chaetae, mouth arts, anterior sensory appendages, dioecious, some septa lost, many segments. Used for locomotion: power and recovery stroke (alternating on each side). Anterior sensory appendages: antenna, eye spots, mouth spots. Senitary: lose bilateral sysment a, increase in number of anten with function as tencticale, and reduction in size and number of parapodia: except chaetopterus: suspension feeder inside u-shaped burrow. Use adapted large parapodia to hold mucus to capture food and bring down to mouth. Reproduction: no permanent gonads, temporary swelling of tissues, gametes are dumping into coelomic cavity and moved ouside the body for external fertilization.
