Phylum Mollusca: The Soft Bodies!
Defining Characteristics
- Large ventral muscular foot
- Visceral mass located dorsal to the foot
- Tissue layer called "mantle" covers the visceral mass
- heterotrophic, multicellular
- shell (sometimes)
- bilateral symmetry
- not segmented
- true coelom
- digestive system: food tubes with mouth and anus
- open circulatory system
- 4 Classes: Polyplacophora, Gastropoda, Bivalvia, Cephalopoda
Clam Worksheet
Squid Dissection: Analysis
1. There are 8 arms on each squid and only 2 tentacles. The tentacles are generally longer than the arms. Both the tentacles and the arms have suckers on them, however the tentacles have more suckers. The arms are typically used to hold prey, but both can be used to capture prey.
2. They both have a large ventral muscular foot, visceral mass located dorsal to the foot, a mantle covering the visceral mass. Bivalves generally have 2 hinged shells, are filter feeders and use gills for respiration and filter feeding. Cephalopods are more evolved than bivalves, have vertebrate eye, are capable of learning, and a greatly reduced shell.
3. My squid was a boy. I determined this by looking at the cecum. The white milky colour indicated that the squid is a male.
4. Food enters the body through the mouth, and it travels through the digestive system of the squid. Nutrients are absorbs as the food is being digested. Waste is eliminated through the anus of the squid.
5. The short distance between the hearts and the gills allow for better exchange of oxygen and carbon dioxide (respiratory function)
2. They both have a large ventral muscular foot, visceral mass located dorsal to the foot, a mantle covering the visceral mass. Bivalves generally have 2 hinged shells, are filter feeders and use gills for respiration and filter feeding. Cephalopods are more evolved than bivalves, have vertebrate eye, are capable of learning, and a greatly reduced shell.
3. My squid was a boy. I determined this by looking at the cecum. The white milky colour indicated that the squid is a male.
4. Food enters the body through the mouth, and it travels through the digestive system of the squid. Nutrients are absorbs as the food is being digested. Waste is eliminated through the anus of the squid.
5. The short distance between the hearts and the gills allow for better exchange of oxygen and carbon dioxide (respiratory function)