Roundworms

• Phylulm Nematoda (Thread-Worm)

Other Names

• Nematodes

Appearance

• No body segments or legs
• Body is tapered at both ends
• Young resemble adults
• No blood vessels or lungs

Behavior

• Shed an outer skin or cuticle about four times to reach adulthood
• Muscles run tip-to-tip under the skin, so roundworms can only bend side-to-side
• Cannot crawl or lift themselves
• Swimming looks like aimless thrashing
• Uses suspended animation to survive dry periods and cold

Aquatic Habitat

• Live in still or quiet water
• Found in mats of decomposing vegetation

Reproduction

• Most species have separate sexes
• Lay tremendous numbers of eggs

Feeding Type

• Muscular throat (pharynx) pulls food in
• Simple digestive system consists of a mouth, throat, gut and anus
• Decomposers that feed on decaying plant material

Pollution Tolerance

• Pollution tolerant
• Large numbers may indicate poor water quality, nutrients and organic pollution
• Thrives on vegetation growing in nutrient enriched water