Digging through the Facts of Worms

By: Audrey Kent- Mitcham Period 2

Background Information

Lumbricus terrestris

The Lumbricus terrestris (common earthworm) has a body that is round with a flat tail. It's body is segmented with rings containing setae that help with movment. Earthworms play a vital role in fertilizing soil to help plants grow. Earthworms are hermaphrodites, meaning they contain both male and female reproductive organs but they cannot self-fertilize.

Habitat

Earthworms are located all over the world except the driest and coldest regions. They mostly live in the forest and are commonly found in moist soil with a slightly acidic Ph level that can vary in location.

Predators

Worms are the base of many food chains and are prayed on by countless species of birds, snakes, mammals, invertebrates and and many other organisms. They are also prone to parasites such as the protozoa that can be located in their blood.

Prey

Earthworms consume decomposed vegetation and dung but manly consume soil.

Ecological Niche

Earthworms are divided into three main groups; Epigeic earthworms located on the surface of the soil, Endogeic earthworms located in the top soil at 10-30 cm, and Anecicare earthworms that can be located up to 300 cm deep in the soil. Epigeic earthworms feed on decomposing vegetation and dung to produce fertile soil for the environment. Endogeic earthworms consume organic matter and soil to help fertilize soil. Anecicare earthworms take in organic matter and go to the surface of the soil to feed. All three groups of worms are eaten by specific predators that fit their niche.
The Amazing World Of Earthworms In The UK - Springwatch - BBC Two

Ecological Adaptation

Epidic earthworms have adapted to better survive being so close to the surface. These earthworms tend to be smaller with darker skin that helps protect from UV rays and provides camouflage in the soil. They also are quicker to escape because they are easier targets to predators. Endogeic earthworms have some pigmentation and can be as long as 2.5-30 cm, They have less muscles than Epidic earthworms because they don't require a quick escape from predators. Anecic earthworms burrow deap into the soil and only go to the surface for food. They are usually pale worms that move very slowly because they live deep in the soil and have little to no muscle. These earthworms can be from 3 to 140 cm long.

Evolutionary Relationships

Objectives

Students will be identifying various parts of an earthworm and studying the external and internal anatomy of it. While dissecting the earthworm, they will study the digestive system and examine how food travels through the worm. Students will also be able to explain the importance of many of the worms physical adaptation.

Earthworm Dissection

Earthworm Anatomy

Digestive System

The digestive system of an earthworm consist of many vital organs that work together to intake, digest, and absorb nutrients from the soil. Food that the worm consumes first enters its mouth, then travels to the pharynx, through the esophagus, crop, and gizzard, and down its intestine. The digestive system also works with the circulatory, endocrine and excretory system. The circulatory system receives nutrients absorbed from the digestive system and then send a signal to the endocrine system to increase digestion. While the digestive system absorbs the remaining nutrients the excretory system removes unwanted material through the worm's anus.

Dissecting earthworms in person

Dissecting the earthworm ended up being really fun and a great hands on experience. I learned a lot about how the worm's internal organ systems work together to form a functioning body. It was interesting seeing the worm cut open in real life and I think it was a better learning experience.

Cross Unit Content

Ecology

The article in the link below is very helpful and allows you to truly understand earthworm ecology.

Evolution

The evolution article in the link below has great information on why earthworms are like they are now.

Taxonomy

Kingdom: Animalia

Phylum: Anndelida

Class: Clitellata

Order: Haplotaxida

Family: Lumbricidae

Genus: Lumbricus

Species: terrestris

Human Impact/Influences

Humans have had a great impact and influence on earthworms. Learn more in the article in the link below.

Fun Facts!!!

Did you know...

  • There about 6,000 species of earthworm found all around the world.
  • Earthworms can live up to 8 years..
  • Earthworms breath through their skin.
  • An Australian species of worm can shoot its lubricating fluid up to 12 inches through its pores.
  • It takes a year for an earthworm to grow to full size.
  • There are blue worms found in Australia that can grow to 2 meters long,

do you know earthworms? quiz yourself!

Citations


  • "Earthworm Adaptations." Science Learning Hub RSS. N.p., n.d. Web. 08 Apr. 2014
  • "The Amazing World Of Earthworms In The UK - Springwatch - BBC Two." YouTube. YouTube, 06 June 2012. Web. 09 Apr. 2014.
  • "Earthworm (Lumbricus Terrestris)." Earthworm Videos, Photos and Facts. N.p., n.d. Web. 08 Apr. 2014.
  • "Earthworm." Wikipedia. Wikimedia Foundation, 04 May 2014. Web. 08 Apr. 2014.
  • "Niches within Earthworms' Habitat." Science Learning Hub RSS. N.p., n.d. Web. 07 Apr. 2014.
  • "WormWatch: Ecology." WormWatch: Ecology. N.p., n.d. Web. 08 Apr. 2014.
  • "Earthworm · University of Puget Sound." Earthworm · University of Puget Sound. N.p., n.d. Web. 09 Apr. 2014.
  • "Wood Turtle (Glyptemys Insculpta)." Wood Turtle Photo. N.p., n.d. Web. 09 Apr. 2014.
  • "Alex Wild." Alex Wild TrapJaw Ants Gallery RSS. N.p., n.d. Web. 09 Apr. 2014.