This earthworm lab is a revised version of the observation lab that I have used for years. I wanted to make the lab more open-ended and include terminology within the lab instead of expecting them to know it from their notes or textbooks. Taxonomy chapters on annelids and other invertebrates are being phased out, and I would rather students explore these terms within the context of the investigation.
In the first section, students are introduced to the idea of bilateral symmetry as the observe how the worm moves and how it responds to gravity (geotaxis).
Students then compare their earthworm to other earthworms in the room to learn and discover that there are no male or female earthworms. The term morphotype is introduced here though only to describe how different animals within the same species can have different appearances.
Finally, students perform a few experiments to determine what senses an earthworm has, focusing on how animals that are heterotrophs use those senses to find food and avoid danger.
A CER (claim, evidence, reasoning) section asks students to justify their claims with evidence about which senses the earthworms have.
Grade Level: 9-12
Time Required: 45-55 minutes