PHYLUM ANNELIDA Flashcards
Trait of remaining protostomes?
Segmentation/metamerism
Where is the mouth and anus located in the annelids?
Mouth - behind an apical prostomium (=acron)
anus - terminal pygidium
2 big consequences of metamerism
- Functionally significant (allows control of shape)
2. Developmentally significant (allow segments to develop independently
What is tagmatization?
The body of annelids have blocks of segment called tagmata which are distinct from other blocks of segments and perform different functions
What are other characteristics of phylum Annelida?
Long, fully segmented worms with complete gut and terminal anus
Mostly closed circulatory system
Paired segmental proto- or meta-nephridial systems
Segmented nervous system
Marine segmented worms
Phylum Polycheata
Describe the prostomium ans peristomium of the polycheates
Prostomium: Complex with tentacles and sense organs
Peristomium: surrounds mouth and may have tentacles, no parapodia
Describe each segments of the polycheates
Have paired, paddle-like parapodia, bilobed and contain many setae
Active, often predatory. Has well developed parapodia + sense organs. Have similar segments and eversible pharynx.
Errantia
Burrow/tube living, particle feeders. Have reduced parapodia + sense organs. Fixed pharynx
Sedentaria
Earthworms and relatives belong to the phylum __________.
Oligochaeta
Qualities that the oligochaete share with polychaete are:
Pro- and peristomium
Highly segmented body
Compartmented coelom
Paired, segmented ventral nerve cords
Qualities that differentiate the oligochaete from polychaete?
No parapodia Few setae Small, simple prostomium (no sensory appendages) Longitudinal muscles not in bundles Hermaphroditic Permanent gonads in a few segments Clitellum
What is the part of the oligochaetes that secretes a cocoon to hold eggs?
Clitellum
How does oligochaete move?
Burrow via retrograde peristaltic waves of body wall muscle
