The Life of an Earthworm

Virtual Dissection Lab

Lumbricus terrestris

The earthworm aka Lumbricus terrestris is a common species that has an important niche/role in its environment. It is crucial to the fertilization of soil. The earthworm's body is relatively round, but it has a flat tail. The bodice is clearly segmented with rings, and small hairs project from the body which aid the worm in movement. Earthworms are hermaphrodites, organisms that posseses both female and male reproductive organs. However, self-fertilizations doesn't occur.

Objectives!

Students will be learning about the external and internal anatomy of an earthworm. By disecting the earthworm , the students will learn more about the organs specific to the digestive system and their functions. Students will also learn about how an earthworm contributes to its ecosystem.

Background Info!

Earthworm Dissection

Earthworm Anatomy

Digestive System

Earthworms’s digestive systems are very important to their survival. It is made up of the mouth, pharynx, esophagus, crop, gizzard and intestine. The function of the digestive system is to intake, digest, and absorb food and nutrients from the soil into the earthworm's body. The soil travels through the organs and down the intestine. The digestive system interacts with the circulatory system to get the nutrients absorbed from the soil and dead matter spread throughout the body (using the bloodstream). The circulatory system also sends signals to the endocrine system to release enzymes that speed up digestion. The digestive system also works very much with the excretory system. When the digestive system is filtering the nutrients, the excretory system is secreting the unwanted materials through the anus.

Symbiotic Relationships

Earthworm's Symbiotic Relationship with Rockdust. Enjoy!

TRophic level

The earthworm belongs to the "decomposers" trophic level. This is the last (5th) trophic level.

Population dynamics

The population of earthworms fluctuates along with the seasons. In wetter, more humid seasons, more earthworms are prone to survive. Also, seasons of growth like spring are favorable because there is more dead plant matter to decompose. Earthworms do much better in soils with organic fertilizer than soils receiving inorganic, processed fertilizers. Below is an article relating to this that you might find interesting!

Humans Impacts on Earthworms

evolution

Read this interesting article about the earthworm's response to environmental changes!

Facts about Earthworms you Probably did Not Know!

  • Earthworms do not have eyes but they do possess light and touch sensitive organs
  • earthworms breathe through their skin
  • in one day, earth worms eat up to a third of their weight
  • earthworms may live up to 6 years!
  • the longest Lumbricus terrestris ever recorded was 30 cm long and weighed 11.2 g!

Map of most Common Earthworm Locations

My Experience

Dissecting an earthworm was both fun and a great learning experience. Hands-on dissection allowed me to clearly see the external and internal anatomy. It was very exciting and I learned much about the earthworm's organs and their functions.

Below are some pictures from the earthworm dissection we did in class:

Feel like you know more now? Quiz yourself!