Are squids cephalopods1/4/2024 ![]() ![]() The name cephalopod ("head-foot") refers to the large, well-developed head and the prominent foot of tentacles. (Ocean water is about 35 PSU, or 35 percent salinity, or 3.5 percent salt.) Cephalopods cannot tolerate freshwater, but a few species do tolerate more or less brackish water none are found at salinities less than 17.5 PSU (practical salinity units) (Vecchione 2006). Because of their highly developed neural organs, cephalopods are valuable experimental animals in biomedical and neurophysiology research.īeyond these values, cephalopods provide aesthetic value, serving as popular focal points in movies, animated cartoons, books, artistic drawings, and marine aquariums, and touching upon people's imagination and ability to experience beauty.Ĭephalopods are found in all the oceans of the world and at all depths, from 0 to over 5,000 meters (Vecchione 2006). Cephalopods protein is considered to be low calorie and includes unsaturated fatty acids, which are considered to have health benefits, including lowering risk of heart disease (Okuzumi & Fujii 2000). Today, well over one million metric tons are caught each year (Vecchinone 2006). Such has been the case for thousands of years Plato and Aristotle both describe fishing methods (Lane 1960 Wood 2001). Commercially, cephalopods are increasingly being targeted by the fishing industry. Ecologically, they have key roles in food chains, preying on fish, crabs, shrimps, and other mollusks, and being consumed by whales, birds, fish, and seals. Two important extinct taxa are Ammonoidea, the ammonites, and Belemnoidea, the belemnites.Ĭephalopods are important ecologically, commercially, and scientifically. Almost all belong to Coleoidea Young (2006) recognizes only six definitive living species of the once abundant and diverse Nautiloidea. There are around 800 known extant species of cephalopods, although an estimate 10,000 or more are known from the fossil record. In the Nautiloidea, the shell remains this subclass includes the nautilus. In the Coleoidea, the mollusk shell has been internalized or is absent this subclass includes the octopuses, squids, and cuttlefish. The class Cephalopoda contains two extant (living) subclasses. The highly developed neural organs allows them to have an excellent capacity to learn and remember nonetheless, most are short-lived, in the order of months or a few years. Cephalopods have the most complex nervous system among invertebrates, and large and image-focusing, vertebrate-like eyes. Cephalopods are characterized by bilateral body symmetry, a prominent head, and a modification of the mollusk foot into the form of arms or tentacles surrounding the mouth, which has beak-like jaws. Cephalopods ( Greek plural Κεφαλόποδα (kephalópoda) "head-foot") are marine mollusks (phylum Mollusca) of the class Cephalopoda, a group that includes the familiar octopus and squid.
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