i am allergic to shellfish and cats.
[{"role": "system", "content": "Shellfish is a culinary and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some kinds are found in freshwater. In addition, a few species of land crabs are eaten, for example \"Cardisoma guanhumi\" in the Caribbean. Despite the name, shellfish are not a kind of fish, but are simply water-dwelling animals. Many varieties of shellfish (crustaceans in particular) are actually closely related to insects and arachnids, making up one of the main classes of the phylum Arthropoda. Cephalopods (squids, octopuses, cuttlefish) and bivalves (clams, oysters) are molluscs, as are Gastropods (aquatic species such as whelks and winkles; also land species such as snails and slugs). Familiar marine molluscs used as a food source by humans include many species of clams, mussels, oysters, winkles, and scallops. Some crustaceans commonly eaten are shrimp, lobsters, crayfish, and crabs. Echinoderms are not as frequently harvested for food as molluscs and crustaceans; however, sea urchin roe is quite popular in many parts of the world. Most shellfish eat a diet composed primarily of phytoplankton and zooplankton.\n"}, {"role": "assistant", "content": "I've always thought shellfish were ancient, like they have been around since the dinosaurs or something."}, {"role": "user", "content": "I bet shellfish back then were much larger than they are now. T-rex was just a glorified reptile after all."}, {"role": "assistant", "content": "It sort of validates my theory because shellfish are part the crustacean family and they have been around for 8 millennia."}, {"role": "user", "content": "The sea is vast, so it's there are plenty undiscovered shell fish probably in the deep ocean."}, {"role": "assistant", "content": "That is very interesting. Believe it or not but many varieties of shellfish are closely related to insects and arachnids(spiders), making them close to the main classes of Arthropodas."}, {"role": "user", "content": "Hold on! How is that even possible. Shellfish don't even have legs like insects of any kind."}, {"role": "assistant", "content": "I don't think it's mainly about legs or anything. But it's that arthropods have invertebrates and exoskeletons segmented bodies sort of like spiders, so I think that's the distinction."}, {"role": "user", "content": "I just find it amusing that shellfish just one day decides to just take their shell off and started walking on to land."}]