HOW TO: Dissect and Earthworm

Earthworm (Oligochaeta)

Background

Earthworms can be found all over the world, the ones that live under the ground get their nutrients from the dirt. The reason that earthworms come to the surface of the Earth when it rains is because the earthworm breathes through its skin and its skin has to stay moist, so when the earthworm is placed in a position with water it thrives. Earthworms eat dirt, they eat things such as dead leaves and roots found in the soil. They also eat small living bacteria that is found in the soil. Earthworms do not have ears or eyes, they have one side of their body that is more sensitive to light than the other. 

External Anatomy 

Clitellum— synthesizes a reproductive sac of mucus

Septum— the structure within segments that connects the skin and internal organs

Anterior end— end where the mouth is located

Posterior end— end where the anus is located

Male Genital Pore— opening where sperm from worm is ejected during mating

Internal Anatomy 

Pharynx— sucks the food into the worm

Seminal Vesicle— stores the sperm of the worm

Gizzard— grinds the food for the worm

Dorsal blood vessel— carries the blood to the anterior end

Ventral blood vessel— carries the blood to the posterior end 

Crop— temporarily stores the food

Aortic arches— pump the blood

Incision Guide

Dissection Procedure