How To Learn About Earthworms

Not How To Eat Fried Worms

Objectives

You will be learning about the external and internal anatomy of a earthworm. You will focus on the organs, structures, and functions of the circulatory system. You will also understand the ecological role, human interactions, taxonomy, evolution, and body systems.

Background Info

It's scientific name is Lumbricus terrestris. Their habitat is in soil of meadows, woods, stream banks, and lawns. Earthworm's predatorsare ants, mites, centipedes, birds, rats, mice, and snakes. They prey on dead plant material, some living plants, manure, and dead animals. Their niche is to break down dead matter and act as decomposers. For ecological advantages they formed a stream line body with setae that help the worm move though the soil. The earthworm ejects its pharynx from its mouth in order to obtain food.

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Taxonomy

Taxonomy of the earthworm is kingdom Animalia,phylum Annelid, class Clitellata, order Haplotaxida, family Lambricicdae, genus Lumbricus, and species Terrestris.

Human Interaction

Earthworms help increase soil fertility by breaking down the soil.

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Evolution

  • An earthworm has a streamlined body with no antennae or fins or arms or legs! This streamlined shape is an adaptation to living in narrow burrows underground and the need to move easily through the soil.
  • Many earthworms secrete a mucus (coelomic fluid) that helps them to move more easily through the soil.

Circulatory System

The earthworm like many more complex organisms has a closed circulatory system, meaning that its blood is confined to blood vessels and its blood is recirculated so it gets maximum use. An earthworm has neither lungs nor gills but uses its body's great surface area to absorb oxygen from the soil. The oxygen is taken in by the dorsal blood vessel and travels to the five aortic arches (hearts) by the esophogus where it is pumped to the lower, ventral blood vessel. The ventral blood vessel pumps the blood to all segments and organs in need of oxygen. In each segment, there is a small blood vessel that sends the blood from the ventral blood vessel back to the dorsal blood vessel, thus completing the loop (Musurca).

Facts

  • Charles Darwin spent 39 years studying earthworms more than 100 years ago.

  • Worms are cold-blooded animals.

  • Worms can eat their weight each day