Earthworm Dissection

Photo Credit: All photos taken from http://www.flushing.k12.mi.us/srhigh/mignerey/web%20dissections/earthworm%20web/Frameset.htmSome content from: http://www.scienceclass.com/dissect/teacher_materials/glossary/earthworm_glossary.htmlVarious videos from both www.YouTube.com and www.arkive.com

External Anatomy

• Cuticle – keeps the worm from drying out

• Dorsal – top part

• Ventral – bottom part

• Clitellum- makes mucus that dries up to form a cocoon

• Prostomium – covers the mouth of the worm

• Mouth- opening at the end allowing the intake of food consisting of particles of both living and dead substances

• Setae – bristle like structures that help the worm move

• Sperm Duct – openings in which sperm can pass through

• Sperm groove – sperm moves along here from sperm duct to another worm

• Oviduct- tube through which eggs pass

• Anus – where excrement (poop) comes out

Internal Anatomy

Circulatory System

Go To Nervous System

Nervous System

• Ganglion- group of nerves. In the earthworm, there is a pair of ganglia in each segment and a cerebral ganglia acts like a brain

Excretory System

• Nephridium- filters wastes. Almost each segment of the worm has a pair of nephridia.

Digestive System• Food goes from the:

Mouth Pharynx Esophagus Crop Gizzard Intestine Anus

• Anus – where excrement (poop) comes out

Reproductive System

• Seminal vesicles- store sperm produced by the earthworm

• Seminal receptacles- paired organs that store sperm received from another worm during copulation

How do Earthworms Mate?

• Earthworms are hermaphrodites which means they have both mail and female body parts

• Worms line up head to tail

• Slime coats the clitellum

• As they do this the tube passes over the sperm ducts and picks up sperm

• Down the sperm groove

• And mixes with eggs that come out of the oviduct

•When free of the slime tube, the cocoon closes up and the sperm and eggs mix.

•This sac is carried by a worm until baby worms have developed, at which point the sac breaks open and they squirm free.