Earthworm Lab Preview

April 16, 2012

General Terms for an Animal’s Structure:

Dorsal – top side

Ventral – bottom side

Anterior – front of the earthworm; where the mouth is located.

Posterior – back end; where the anus is located. Anterio

r

Ventral

Dorsal

Anterior

Dorsal

Ventral

Posterior

Posterior

Earthworm External Features:

Segments – sections of the body

Clitellum – smooth band around the earthworm

that forms a cocoon for fertilized eggs during

reproduction.

Setae – bristles found along the ventral side of the earthworm that help it move.

Mouth – takes in food; closer to clitellum; anterior end of worm.

Anus – releases wastes; posterior end of worm.

Segment

Clitellum

Mouth

Anus

Setae

Earthworm Body Systems

Circulatory System – How the blood circulates through the body.

Aortic Arches (hearts) – pumps blood.

Blood Vessels – both dorsal and ventral sides of worm.

Circulatory System in RED

Earthworm Body Systems

Nervous System – How the worm senses and feels things.

Brain – very difficult to see; near segment 2.

Nerve Cord – only on ventral side of worm.

Nervous System in

YELLOW

Earthworm Body Systems

Reproductive System – Making more earthworms.

Clitellum – holds fertilized eggs.

Seminal Vessicles – sperm is made here.

Seminal receptacles – sperm is stored here.

Earthworms are hermaphrodites meaning they

have both male and female structures.

Clitellum

Seminal Vesicles and receptacles

Earthworm Body Systems

Digestive System – Taking in food and breaking it down.

Mouth – takes in food; anterior end. Pharynx – muscular tube leading to the esophagus. Esophagus – tube going from the pharynx to the crop. Crop – stores food. Gizzard – grinds food. Intestine – main organ

in digestion. Anus – releases wastes.

Digestive System in GREEN

Earthworm Body Systems

Excretory System – Gets rid of wastes.

Nephridia – little coiled tubes that get ride of wastes throughout the worm.

Anus – releases wastes.

Anus