What are crustaceans and molluscs?
Crustaceans are part of the Phylum Arthropoda which crabs and shrimps. Molluscs include bivalves, octopuses, and snails. A defining characteristic in Molluscs is the radula which is the structure that all molluscs other than bivalves use to eat. Also in all molluscs expect octopuses and squids there is an external or internal shell. Crustaceans can be differentiated from other arthropods by the number of antennae that they have. They have 2 pairs of antenna (think shrimps) versus insects who have one or zero (ants only have one pair and spiders have zero.). Reproductive wise most molluscs lay or release large amounts of eggs with little parental care (they just release them into the water). Crustaceans do a considerable amount of parental care such as lobsters or crayfish who carry or guard their eggs. Nutrition would depend on the specific species since some are herbivores, some omni and other carnivorous.
