-
Mollusca characteristics
- -Sluggish to very swift
- -Includes squids, oysters, octopus, slugs, snails, clams
- -50,000 species
- -Soft bodied
- -Microscopic to 18 meters long
-
Mollusca general characteristics
- -True coelom
- -All organ systems present
- -Open circulatory system
- -Closed circulatory system in some cephalopods
- -Mantle-secretes shell
- -Radula and muscular foot
- -Marine, freshwater, terrestrial
-
-
Mollusca bad because
- Destructions
- -Shipworms damage wooden ships
- Intermediate host for parasites (snails)
- Slugs damage crops
-
Mesentaries do what?
Hold organs in place
-
Coelom
- Body cavity with parietal peritoneum (mesodermal epithelium)
- Allows for extensive organ development
- Allows organs not to crowd other organs
-
Coelom general characteristics
- -Filled with coelomic fluid
- Transports nutrients and wastes in small organisms
- Allows for networks of blood vessels
- Acts as a hydrostatic skeleton
-
In molluska, coelom is not highly developed..why?
Limited to space around heart and gonads
-
-
Most active region of mullusca
-
Head-foot region made-up of
- -Feeding organs
- -Specialized sensory organs (simple to complex eyes)
- -Locomotor organs
-
Radula
- Tongue-like organ
- Teeth point backwards to tear off food
- -Not found in bivalves
- Acts as a conveyor belt to digestive tract
- Teeth are replaced with new
-
Pattern and number of teeth on radula are
- Specific to species and are used for classification purposes
- up to 250,000 teeth
-
Foot is
- Posterior to mouth
- Locomotion
- Attachment to substratum
- -Siphon=modified foot. Found in cephalopods (squids/octopus)
- For jet propulsion
|
|
