1. Characteristics

2.  Where do they live?  Oceans  Fresh water  Terrestrial  What kinds of symmetry do they have?  Bilateral

3.  Give examples of the three classes: 1. Class Polychaeta (many bristles)  EX: Chris Tree 2. Class Oligochaeta (few bristles)  EX: Earthworm 3. Class Hirudinea (no bristles)  EX: Leeches

4.  Bilateral  Coelomate: true coelom lined with mesoderm  Body is divided into segments  All organ systems present (digestive, circulatory, respiratory, excretory, nervous, muscular, reproductive)  Bristles or setae (on most)

5.  Most annelids reproduce sexually  Some have separate sexes – male/female  Earthworms and leeches are hermaphrodites: Each worm produces sperm and eggs Rarely fertilize their own eggs Two worms exchange sperm Fertilization occurs in the clitellum

6.  Filter feeders to predators  Get their food using a pharynx  In earthworms: Food travels down the esophagus towards the crop (can be stored), and through the gizzard where it is ground into smaller pieces Food is absorbed in the intestine

7. Coelomate – fluid-filled body cavity lined with mesoderm Setae – bristles attached to segments crop – stores food in digestive system gizzard – grounds food into smaller pieces closed circulatory system – blood contained within a network of blood vessels nephridium – excretory organ; filters fluid clitellum – reproductive organ which secretes a mucus ring into which eggs and sperm are released.