Exciting Earthworm Experience

Earthworm Lab by Gabby Trudo, Mitcham, period 6

Objectives

To explore the external and internal parts of an earthworm, and to understand the functions of their organs.

Background Information

Earthworms are the largest worms in the class Oligochaeta. There are many different kinds of earthworms, such as Amynthas Siam, an Asian earthworm; Eisenia fetida, a worm that lives in decaying plant matter and manure; and Lumbricus terrestris, the earthworm that was dissected in class. Lumbricus terrestris burrows into the ground and lives in their burrow temporarily until they are ready to feed. These earthworms feed off leaves and occasionally dead insects and feces. They originated in Europe but soon found their way all around the world and can now be found on every continent. Lumbricus terrestris are considered an invasive species in central North America. Lumbricus terrestris is endangered in Europe where it originates due to the invasive Australian and New Zealand flatworms. Earthworms help create more fertile soils by converting large pieces of organic matter into rich humus. The holes that earthworms create while burrowing in the ground help maintain soil structure and moisture while also improving drainage. European soils are now suffering due to the scarcity of the once common worm.

Phenomenal Pictures of Enticing Earthworms

The Circulatory System

The earthworm's circulatory system keeps blood, nutrients, and water flowing throughout the body. It is a closed system that consists of aortic arches, dorsal blood vessels, and ventral blood vessels that all pump blood to organs. There are five pairs of aortic arches that pump blood into the dorsal and ventral vessels. Dorsal vessels pump blood into the front or dorsal side of the earthworm's body, while the ventral vessels pump blood to the back or ventral side of the earthworm's body.

Fun Facts

Earthworms are hermaphrodites, meaning that they carry both male and female sex organs. Several earthworms are parthenogenetic, meaning that they can reproduce asexually. An earthworm can burrow six feet deep and its entire body is covered in taste receptors called chemoreceptors. Lumbricus terrestris are assumed to have a life span of approximately four to eight years in the wild. Some of these earthworms can grow over a foot in length. These earthworms are known to regenerate or grow back parts of their body that have been damaged or completely severed, depending on the severity of the injury.
Earthworm Anatomy

Bibliography

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