Key Characteristics
*Roundworms have no segmentation but do have bilateral symmetry
*They are triploblastic pseudocoelom with a digestive system with two openings (mouth and anus)
*Have a complete digestive tract where nutrients are transported through the body in the pseudocoelomic fluid
*The body plan is often called a tube-within-a-tube
*Roundworms have longitudinal muscles that produce a thrashing motion
*Reproduce sexually only, with internal fertilization
*There are 15,000 known species of roundworms
Habitat
Round worms inhabit virtually every habitat in the seas, freshwater, and on land, although some species have very specific habitats. Nematodes generally live in the spaces between aquatic sediments or on the sediment surface. Non-parasitic nematodes are adapted to 'swimming' along the bottoms of streams and lakes.
Interesting facts
1. Roundworms can reach up to 20 inches long
2. They can cause blindness
3. You would be most likely to encounter them in warm regions
4. Each animal has a roundworm that is specific to that species
5. If you get an infection the symptoms appear about 1 year later
Five examples
1. Ascaris
*Roundworms have no segmentation but do have bilateral symmetry
*They are triploblastic pseudocoelom with a digestive system with two openings (mouth and anus)
*Have a complete digestive tract where nutrients are transported through the body in the pseudocoelomic fluid
*The body plan is often called a tube-within-a-tube
*Roundworms have longitudinal muscles that produce a thrashing motion
*Reproduce sexually only, with internal fertilization
*There are 15,000 known species of roundworms
Habitat
Round worms inhabit virtually every habitat in the seas, freshwater, and on land, although some species have very specific habitats. Nematodes generally live in the spaces between aquatic sediments or on the sediment surface. Non-parasitic nematodes are adapted to 'swimming' along the bottoms of streams and lakes.
Interesting facts
1. Roundworms can reach up to 20 inches long
2. They can cause blindness
3. You would be most likely to encounter them in warm regions
4. Each animal has a roundworm that is specific to that species
5. If you get an infection the symptoms appear about 1 year later
Five examples
1. Ascaris
2. Hookworms
3. Trichinella
4. Pinworms
5. Filarial worms
This video is a brief overview on the basics about nematoda like where they live, what they do, and what they are. One strength about this video is that the information is very easy to understand and is accurate. One weakness is the visual content is a little graphic.