Anusha De 4/9/14 Vu-PAP Bio- P3
- Kingdom: Animalia - eukaryotic, multicellular
- Phylum: Annelida - body made up of segments separated by a septum
- Class: Clitellata - clitellum (secretes clitella or cocoon during reproduction)
- Subclass: Oligochaeta - setae, no lateral appendages
- Order: Opisthopora - terrestrial worms, paired testes
- Family: Lumbricidae - largest earthworm family, contains 33 species of earthworms
- Genus: Lumbricus
- Species: Terrestris
Earthworm at a Glance
Lumbricus terrestris, otherwise known as earthworms, are reddish-brown organisms with cylinder-shaped bodies that can range from 7 to 35 centimeters in length. An earthworm’s body is divided into ring-like segments called annuli. An earthworm can be made up of anywhere from 100 to 150 annuli. Annuli are covered in setae, or small bristles that allow the earthworm to move and burrow through in the soil in which it lives. The earthworm’s streamlined body shape with no limbs also enables it to move through soil. Other adaptations of the earthworm include a bioluminescent mucus, sensitivity to vibrations and light, and circular and longitudinal muscles. Subsequently, earthworms can be found in a variety of habitats, but they are rare in cold or dry places. Although they are native to Europe, earthworms are abundant in North America and western Asia. Earthworms, are also called night crawlers because they are mostly nocturnal animals. During the day, they burrow into the soil, sometimes digging as deep as 6.5 feet. They emerge above ground at night to feed on nutrients from the decomposing organic matter in the soil. Predators of the earthworm include birds, rats, snakes, beetles, and toads. Earthworms are important because they are constantly moving and burrowing through the soil, which mixes it, and fertilizing it through their waste. Humans use earthworms as compost and as bait.
Anatomy and Dissection
Delving Into Digestion: The Digestive System
- mouth - takes in food (soil)
- pharynx - lubricates food and pumps it into esophagus
- esophagus - calcifies food and transport it to crop
- crop - stores food
- gizzard - breaks down food and churns it to a thick paste
- intestine - transports food and absorbs nutrients
- anus - ejects undigested material
- Earthworms are both male and female because they produce sperm and eggs.
- Earthworms breathe through their skin; they do not have any respiratory organs.
- The largest earthworm ever found was 22 feet long, and located in South Africa.
- Earthworm secretions contain nitrogen.
- Charles Darwin spent over 39 years studying earthworms.
- Earthworms can eat up to a third of their body weight each day.
- There can be up to 1 million earthworms in a single acre of land.
- When a worm is cut in half, the head end will regenerate into a new worm, but the tail will now.
- Tiny stones in an earthworm's gizzard allow it to grind food.
- Earthworms have existed for 120 million years.