Cell Cycle and Cell Division - Meiosis
Phylum Platyhelminthes (Flatworms): General Characters
- Grades of Organization: Organ & Organ system.
- Symmetry: Bilateral symmetry.
- Germ Layers: Triploblastic.
- Coelom: Acoelomate
- Habit and Habitat: Mainly aquatic. Endoparasites. Some are free-living.
- Digestive System: Incomplete.
- Respiratory System: Absent
- Circulatory System: Absent
- Reproduction:
- Asexual (fragmentation) and Sexual.
- Hermaphrodite.
- Internal Fertilization.
- Development is indirect.
- Many larval stages.
- Unique Features:
- Unsegmented, dorso-ventrally flattened body (except tape worms).
- Excretion and osmo-regulation by Flame cells.
- Parasites have Hooks & suckers.
- Some absorb nutrients from the host through their body surface.
- Examples:
- Taenia solium (Tape worm)
- Fasciola (Liver fluke)
- Planaria (shows high regeneration capacity).
