How do flatworms differ from roundworms in terms of body structure and...
Body Structure
Flatworms and roundworms are both members of the phylum Nematoda, but they differ in their body structure and organization.
1. Flatworms:
- Flatworms, also known as Platyhelminthes, have a flattened body shape.
- They exhibit bilateral symmetry, meaning their body can be divided into two equal halves along a central axis.
- They have a distinct head region that contains sensory organs like eyespots and chemoreceptors.
- The body is dorsoventrally flattened, which allows them to live in aquatic environments or damp terrestrial habitats.
- They have a simple body plan without a body cavity (acoelomate) and a blind gut (a single opening serving both as a mouth and anus).
2. Roundworms:
- Roundworms or Nematodes have a cylindrical, elongated body shape.
- They also exhibit bilateral symmetry.
- They have a pseudocoelom, a body cavity that is not completely lined with mesodermal tissue.
- They possess an alimentary canal, a complete digestive system with separate openings for the mouth and anus.
- They lack specialized respiratory and circulatory systems, relying on diffusion for gas exchange and nutrient distribution.
Organ Systems
Flatworms and roundworms differ in their organ systems as well.
1. Flatworms:
- Digestive System: Flatworms have a simple digestive system with a mouth and a branched gastrovascular cavity that facilitates both digestion and circulation.
- Excretory System: They possess a network of tubules called protonephridia, which help in osmoregulation and excretion of metabolic wastes.
- Nervous System: Flatworms have a ladder-like nervous system with a pair of ganglia (nerve clusters) in the head region and longitudinal nerve cords extending the length of the body.
- Reproductive System: They exhibit a wide range of reproductive strategies, including both sexual and asexual reproduction.
2. Roundworms:
- Digestive System: Roundworms possess a complete digestive system, consisting of a mouth, pharynx, intestine, and anus.
- Excretory System: They have a specialized excretory system called the excretory canal or pseudocoelomic excretory system, which helps in the removal of waste materials.
- Nervous System: Roundworms have a less complex nervous system compared to flatworms, consisting of a ring of nerves around the pharynx and longitudinal nerve cords.
- Reproductive System: They exhibit sexual reproduction, with separate sexes in most species.
Overall, flatworms and roundworms differ in their body structure, with flatworms having a flattened body shape and roundworms having a cylindrical body shape. They also differ in their organ systems, with flatworms having a simpler digestive system and a ladder-like nervous system, while roundworms have a complete digestive system and a less complex nervous system.
To make sure you are not studying endlessly, EduRev has designed NEET study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in NEET.