Unearthing The Earthworm

Earthworm Dissection Pre Ap Biology April 8 2014


The objective of this lab is to learn about the internal and external structures of the earthworm.

Background Information


The scientific name of the earthworm is Lumbricus terrestris and it belongs to the phylum Annelida.


Earthworms have many predators including snakes, birds, and rodents. Earthworms are primary consumers. Earthworms live in humid or slightly cold environments with moist soil; mostly in the the United States, Canada, Europe, and Russia.

Evolutionary Adaptations

In order to get food, earthworms suck dirt into their mouths. As the dirt moves through their digestive system, nutrients and food are separated . They let out coelomic fluid to help them move through the soil more easily. They exchange gases between the environment and it's circulatory system through their skin.

Human impact

Humans have some negative impacts on earth worms. Pesticides and chemical fertilizers that are used during farming often kill the worms.


System Of Focus: Digestive System

The digestive system of an earthworm consists of a mouth, pharynx, esophagus, crop, gizzard, intestine, and an anus. Food enters the mouth first. It it then passed to the pharynx, where it is coated with mucus so it can easily pass through the esophagus. The esophagus takes out acids and harmful things from the food. After that, the food is moved to the crop where it is stored. When it is passed to the gizzard, it is grinded up and mixed. The gizzard also releases enzymes that break down organic material further. The food is then passed to the intestine where it is broken down even more and nutrients is taking out of it. The waste is then excreted out of the anus. The digestive organs are shown below.

Cooperation between organ systems

The digestive system and the circulatory system work together because when the digestive system gets nutrients from food, the circulatory system sends it throughout the body.


The Earthworm