An Earthworm Dissection Lab By: Mariam Moini, Mitcham P2
Background information on Earthworms
The scientific name of the earthworm is the Lumbricina.
Earthworms get their nutrition from many forms of organic matter in soil, such as decaying roots and leaves, and living organisms such as nematodes, protozoans, rotifers, bacteria, and fungi. They will also feed on the decomposing remains of other animals. Snakes, birds, moles, toads and even foxes are known to eat earthworms. Beetles, centipedes, leeches, slugs and flatworms also feed on earthworms.
Earthworms are found all over the world.Most live in muck and mud around freshwater, but some live under the sea, and many live in the soil on land.Moist soil conditions are needed in order for survival.Earthworms are usually found in places where there is moist soil and dead plant material. Earthworms are most abundant in rainy forest areas, but can be found in many habitats on land and in freshwater.
- Some earthworm species can live up 8 years, but it is very rare for them to survive that long. Most are eaten or killed in some other way before they live for one year.
- Earthworms only communicate with each other by touch and taste, but they can feel vibrations, and often avoid predators by sensing their footsteps. They can also sense light and moisture in the air.
- Earthworms' main defense is hiding in their burrows in the soil. They will quickly crawl down into the ground if they detect a predator.
There are approximately 2,700 different kinds of earthworms.
Even though worms don’t have eyes, they can sense light, especially at their anterior (front end). They move away from light and will become paralyzed if exposed to light for too long (approximately one hour)
Digestive system of an earthworm
- Mouth – First part of the digestive system that takes in food
- Pharynx –Food is lubricated after leaving the mouth for easier passage
- Esophagus (5th to 7th segment) - Tube-like structure that leads food out to the crop
- Crop – Stores food as it moves through the system. The food is mixed together in the crop and then passed to the gizzard for the actual process of digestion to begin.
- Gizzard – Grinds and breaks apart food. There are enzymes secreted from the walls of the gizzard that help in the digestion, that is, chemical breakdown of the organic matter ingested. The thick paste so formed is then pushed into the intestine.
- Intestine (15th to 120th segment) – Transports nutrients and soil through the digestive system. It contains bacteria that help in further breakdown of the food. The bacteria act on the food releasing vitamins, proteins, carbohydrates and minerals in the worm body to help it survive.
- Anus – Opening where waste from digestion exits the body
Earthworms Relationship to the Surrounding World