1. Annelids Phylum Annelida: 15,000 species of Segmented Worms

2. Class Oligochaeta “Few bristles” Earthworms = Lumbricus terrestris

3. Class Polychaeta “Many bristles” Marine worms, sandworms

4. Class Hirudinea Leeches

5. Classification Common Name: Earthworm Scientific Name: Lumbricus terrestris Phylum: Annelida Class: Oligochaeta Other: Segmented Worms

6. Characteristics Body Plan: Tube within a tube; Segmentation = repeated units Body Cavity: Psuedocoelom “False Cavity” Symmetry: Radial Cell Specialization: Organs and tissues exist; repeated body segments past a certain point; insurance against injury

7. Life Support Processes Absorption: Intestine runs the entire length of the body Feeding: Soil enters Mouth > Pharynx (esophagus) > Crop (storage) > Gizzard (grinds food) > Intestine Digestion: Intestine = Chemical; Gizzard = mechanical

10. Life Support Processes Respiration: Through the skin, must be kept moist Circulation: Closed System - Dorsal Blood Vessel carries blood to head; Ventral Blood Vessel carries blood to back; Ring Vessel = heart (5 Aortic Arches) Excretion: Anus = solids; Nephridia = liquids

12. Life Support Processes Secretion: Intestine = digestive enzymes; Clitellum = mucus ring to make egg sac Response: Dorsal Ganglia = Brain; no sense organs other than touch receptors in skin Movement: Longitudinal and Circular Muscles, Setae

13. Life Support Processes Reproduction: Sexual; hermaphrodites that exchange sperm; Seminal Vesicle = produce sperm, Seminal Receptacle = receive sperm Support: Muscle tissues

14. Ecological Relationships Condition Soil; release nutrients Detritus Feeders; decompose leaves etc.

15. Body Systems Compared With Humans Nephridia = Kidney Intestine = Small Intestine Pharynx = Esophagus

16. Advancements Over Previous Phylum Closed Circulation Digestive Tract Muscles - greater degree of motion Segmentation = enables different parts of the body to function independently

17. Earthworm Diagram

19. The largest of the Segmented worms is the African Giant Earthworm (Microchaetus rappi). This huge worm can reach a length of as much as 22 ft and can weigh over 3.1 lb!