Earthworm Dissection
Joseph Buks PAPBio 4/7/10
Lumbricus terrestris
Earthworms are a classified in the phylum Annelida. Annelida means "little rings" in Latin. Earthworms can have anywhere from 100 to 150 of these "little rings" better known as segments. An earthworm eats the organic materials in the soil that it lives in creating little burrows which allow the soil to aerate, and lets water and nutrients get deep into the soil helping provide nutrients for plants.
Objectives
Students will learn about the internal anatomy of an earthworm. Students will also learn about the functions of earthworms in the environment and the organs and functions of the organs.
Adaptations
To get to where they are, earthworms have evolved to have segmented bodies, tissues that work together to form organs, and ceolem.
Predators
Predators of earthworms include birds, moles, and humans. Humans use the earthworms as fishing bait or earthworms are accidentally killed when clearing plots of land in industrial farming.
Circulatory System
An important system in earthworms is their circulatory system. Instead of one heart, they possess five aortic arches near the mouth of the annelid. The earthworm has a dorsal vessel (on the dorsal side of the worm) and a ventral dorsal (on the ventral side of the worm). Below is an enlarged picture of the circulatory system.
Interesting Facts
- Earthworms conduct respiration through their skin
- Earthworms are hermaphrodites
- Earthworms can regenerate lost segments on their bodies