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A fun video all about the three main groups of worms. Be sure to head to ngscience.com for a range of related resources for students and teachers.
Worm is the general name given to animals from three different groups – flatworms, roundworms and segmented worms. Worms are multicellular and typically have a long tube-like body and no limbs. All worms have bilateral symmetry. Organisms with bilateral symmetry have a body with a single plane of symmetry which divides it into two mirror images. Most worms reproduce sexually, although some can reproduce asexually.
Flatworms, also called platyhelminths, are simple worms with a soft, flat body. They can be found in salt water, fresh water, and damp land environments. Many flatworms are parasitic. A parasitic organism lives in or on another organism. Most flatworms have a body cavity with only one opening. Food enters the body opening and waste leaves through the same opening.
Roundworms, also called nematodes, are more advanced than flatworms. They have a tubular digestive systems with openings at both ends. Roundworms live in a range of different environments. Many are parasitic and can cause illnesses and diseases in other organisms.
Segmented worms, also called annelids, are the most advanced of the three worm groups. They get their name from their bodies which are divided into segments. Segmented worms have organ systems including circulatory, digestive and nervous systems.
Segmented worms can be found in most wet environments, including underground and in the ocean. Common segmented worms include earthworms, leeches and bristle worms.
