Worm Phylas
Platyhelminthes, Nematoda, and Annelida by BRI :)
Characteristics of a worm
- creeping or burrowing invertebrate
- long, slender, soft bodies
- no limbs
- bilateral symmetry
Phyla Platyhelminthes
- Characteristics: bilateral symmetry, 3 tissue layers with organs and organelles, blind gut, protonephridial excretory organs, generally dorsoventrally flattened, reproduction mostly sexually
Phyla Nematoda
- Characteristics: bilateral symmetry, has more than 2 tissue layers and organs, psuedocoel body cavity, body processes through a gut with a sub terminal anus, covered by a complex cuticle, no circulatory system, nervous system with nerve ring
Phyla Annelida
- Characteristics: bilateral symmetry and veriform, more than 2 cell layers and organs, body cavity is a true coelom, body had divided sections, closed circulatory system, no respiratory organs, sexual reproduction
Platyhelminthes: Dugesia planaria
- free living
- regenerate
- 3 tissue layers
- no respiration system
Nematoda: Ascaris suum
- only has longitudinal muscles
- parasitic
- complete digestive tract
- protected by cuticle
- no respiratory or circulatory organs
Annelida: Lumbricus terrestris
- free-living
- complete digestive tract
- nocturnal
- move using muscle and setae