PYLUM ANNELIDA PYLUM ANNELIDA – segmented worms– segmented worms

AnnelidsAnnelids

• Representative species – common Representative species – common earthwormearthworm

• Have a coelom – fluid filled body cavity Have a coelom – fluid filled body cavity surrounded by a mesoderm (room for surrounded by a mesoderm (room for organs)organs)

• Have a peritoneum (membrane in the Have a peritoneum (membrane in the coelom in which all organs are attached)coelom in which all organs are attached)

• Have 2 sets of muscle tissue. 1. body wall Have 2 sets of muscle tissue. 1. body wall muscles – to move the worm and 2. muscles – to move the worm and 2. digestive system muscles to move food digestive system muscles to move food through the systemthrough the system

Class Oligochaeta: Class Oligochaeta: EarthwormsEarthworms

``It may be doubted whether there are any other ``It may be doubted whether there are any other animals which have played so important a part animals which have played so important a part in the history of the world as the earthworm.``in the history of the world as the earthworm.``

-Charles Darwin, 1881-Charles Darwin, 1881

http://mypeoplepc.com/members/arbra/bbb/id19.html

Class Oligochaeta: Class Oligochaeta: EarthwormsEarthworms

• 2500 species2500 species• Many more cell layers than flat and Many more cell layers than flat and

round wormsround worms• Have blood to carry gases to and Have blood to carry gases to and

from body tissues (circulation)from body tissues (circulation)• Blood in earthworms contains a red Blood in earthworms contains a red

protein hemoglobin (just like in us!)protein hemoglobin (just like in us!)• Have 5 hearts near the anterior end Have 5 hearts near the anterior end

Earthworms cont…Earthworms cont…

• More complex digestive system than More complex digestive system than other worm phylaother worm phyla

• They consume dirt (food and sand They consume dirt (food and sand particles) via mouth, esophogus, particles) via mouth, esophogus, pharynx, and then stores it in the crop.pharynx, and then stores it in the crop.

• After storage, food moves to the After storage, food moves to the gizzard to be ground down, then to the gizzard to be ground down, then to the intestine for digestion and absorption intestine for digestion and absorption into the blood stream.into the blood stream.

• Undigested food moves out the anusUndigested food moves out the anus

Earthworms cont…Earthworms cont…

• Setae are bristles that aid in mvmt.; Setae are bristles that aid in mvmt.; each segment has 4 setae (except each segment has 4 setae (except first and last ones)first and last ones)

• Complex NSComplex NS• Reproduce sexuallyReproduce sexually• HermaphroditesHermaphrodites

Other ANNELIDSOther ANNELIDS

• Class Hirudinea – leeches (blood Class Hirudinea – leeches (blood sucking parasites)sucking parasites)

Class Polychaeta – Class Polychaeta – marine wormsmarine worms

Worm Worm Grunting/CharmingGrunting/Charming

http://www.youtube.com/watch?v=VjRxUVLxdYI

http://www.youtube.com/watch?v=IGviTYCFksE