Flashcards in PHYLUM MOLLUSCA Deck (26):
Name the characteristics of his phylum
Triploblastic, bilaterally symmetrical, unsegmented, true coelom, protostomes
What is some general information about this phylum?
Economy, flatworms are in the 3rd dimension, visceral mass, specialized organs
What does the osphradia do?
Monitor the water flow over the gills/ctenidia
What is the name of the generalised mollusc?
What is a radula, its function and what is it supported by?
Teeth-like conveyer belt for feeding. Primitive grazers have it. Supported by odontophores
What is the shell secreted by and how many layers are there?
The mantle, there are 3
Name the layers of the shell
Periostracum, prismatic & nacreous
Describe the periostracum layer?
Organic layer, dark conchiolin
Describe the prismatic layer?
CaCO2, prisms in the protein matrix
Describe the nacreous layer?
Plate-like, CaCO2 crystals, pearly
How are pearls formed?
Particles become trapped between the nacreous and epidermis layers and irritates the mollusc. It coats it in calcium carbonate
The circulatory system in molluscs is open, true or false?
True, except in Cephalopoda
How many oracles and ventricles does mollusca have?
2 oracles, one ventricle
Name the elements of the c.s
some blood vessels, haemocyanin and the heart is in the coelomic cavity.
What is the pericardium?
The coelomic cavity
What is haemocyanin?
A protein containing copper that transports oxygen in invertebrates
What parts are ciliated in the digestive system of mollusca?
Where do the salivary glands open up to?
Describe the d.s process
Salivary glands secrete mucus, mucus/food string is formed in oesophagus, pulled into stomach by cilia, rotated, protostyle, intra/extra cellular digestion
What is the protostyle?
Food laden mucus mass
What is the excretion process?
The metanephridia drain pericardial cavity and empty into the mantle cavity
What do the gonads arise from?
What is the one word that describes reproduction in mollusca
What is parthenogenesis?
Reproduction via unfertilized gametes
Describe the reproduction process
Egg and sperm are released into the environment and fertilization occurs there