Nematode

Nematodes are a phylum of roundworms, scientifically known as Nematoda.

Nematodes are a phylum of roundworms, scientifically known as Nematoda. They are among the most abundant animals on Earth and occur in marine, freshwater, soil, and host-associated environments. Most species are free-living, but many are parasitic on plants, animals, and humans.

Classification and anatomy

Nematodes are unsegmented worms in the phylum Nematoda. They are typically slender and cylindrical, and many species possess a flexible cuticle and a complete digestive system.

Distribution and habitat

Nematodes occur in soils, freshwater, marine environments, and within plants and animals as parasites. They have been reported from every continent and can live in a wide range of conditions.

Ecology and abundance

Free-living nematodes are common in soil and aquatic ecosystems, where they help process microorganisms and contribute to nutrient cycling. They are widely regarded as one of the most abundant groups of animals.

Parasitism and disease

A smaller number of nematode species are parasitic on humans, livestock, and crops. These include species responsible for intestinal infections, filariasis, and major agricultural losses.

Research importance

Nematodes are important model organisms in biology, especially Caenorhabditis elegans. They are used in studies of development, genetics, and neurobiology.