1. PHYLUM ANNELIDA Segmented Worms

3. CHARACTERISTICS A.Have many segments separated by internal walls called septa. Most segments are identical. Some segments are modified to perform specific functions such as carry eyes, antennae, or other sense organs in different kinds of worms.

4. B.Have a true coelom and a circulatory system with closed blood vessels, some vessels having muscles that pump blood (called “false hearts”).

5. C. The gut or digestive tract begins with a mouth and ends with an anus. Feeding varies from detritus feeders, filter feeders, to parasites and some carnivores.

6. D. Terrestrial annelids breathe through their skin. Aquatic annelids breathe with gills.

7. E. Excretion in annelids is by removal of solid wastes out of the anus. Nitrogenous wastes are removed by means of nephridia, simple tube-shaped excretory organs that function like primitive kidneys.

9. F. Response in annelids is by a well- developed nervous system beginning with a brain at the anterior end of the body above the gut. Two large nerves pass around the gut and connect the brain to ganglia below. A ventral nerve cord runs the entire length of the body. Nerve cells carry messages from sense organs to the brain and help coordinate movements of muscles.

11. G. Annelids have two major groups of muscles in their body walls. Longitudinal muscles from front to rear of the worm. They contract to make the worm shorter. Circular muscles run in circles around the worm body which contract to make the worm skinnier. Marine worms swim using these muscles to wriggle through water. Burrowing annelids use their muscles to force their way through heavy sediment.

12. H. Reproduction is mostly sexual. Some species have separate sexes with external fertilization. Earthworms and leeches are hermaphroditic and undergo internal fertilization.

13. I.The three classes of Annelids are: 1. CLASS POLYCHAETA – Marine worms (Polychaetes) a. Have paddle-like appendages (parapodia) on their body segments tipped with bristles (setae). Filter feeders. b. Live in cracks and crevices in coral reefs, in sand, mud, and piles of rocks, and sometimes in open water.

14. c. May be dull or brightly colored, some iridescent or luminescent. d. Examples: Sea Mouse, Clamworm, Sandworm, Bloodworm, Fanworm, Fireworm.

26. 2.CLASS OLIGOCHAETA – Long slender worms (Oligochaetes) a. Have fewer bristles (setae) than polychaetes, located on ventral surface to help anchor the worm in its burrow. Lack (parapodia). Have hydrostatic skeleton to provide the body with support. Have nephridia, tubules in each segment to excrete wates. b. Feeds on detritus in soil which it sucks in with a pharynx as it moves through soil. Worm wastes, called castings, produce very fertile soil.

27. c. Most live in soil or fresh water, but some are marine. d. Examples: the earthworm (night crawlers, manure worms, red worms, Tubifex worms.

32. 3.CLASS HIRUDINEA - Leeches a. Most live in moist tropical countries but some species extend throughout North America. b. Typically 6 centimeters long up to 30 centimeters long. Have powerful suckers at both ends of body used to attach to host and anchor to rocks, leaves, etc. Lack (parapodia)

33. c. Mostly freshwater parasites but ¼ are carnivores on snails, worms, and insect larva. Swallow their prey whole or suck out the soft parts of the prey from its body.