What is the literal meaning of Mollusca?
Mollusca, meaning “soft-bodied,” is one of the largest phylums in the animal kingdom. The word mollusc (or mollusk) derives from the Latin word “mollis,” which means “soft.” There are an estimated 200,000 species of mollusk worldwide accounting for nearly a quarter of all marine life.
Where does the term Mollusca come from?
The words mollusc and mollusk are both derived from the French mollusque, which originated from the Latin molluscus, from mollis, soft. Molluscus was itself an adaptation of Aristotle’s τὰ μαλάκια ta malákia (the soft ones; < μαλακός malakós “soft”), which he applied inter alia to cuttlefish.
What are mollusks dictionary?
noun. any invertebrate of the phylum Mollusca, typically having a calcareous shell of one, two, or more pieces that wholly or partly enclose the soft, unsegmented body, including the chitons, snails, bivalves, squids, and octopuses.
Does mollusk mean soft?
mollusk Add to list Share. Your pet snail, Sammy, is one example of a mollusk, or a soft, spineless animal. It’s a bit ironic that this term for a large phylum of invertebrates comes from a Latin word that means “soft,” mollis, since many mollusks (or molluscs in Britspeak) have hard shells.
What are the 4 major groups of living mollusks?
The major classes of living mollusks include gastropods, bivalves, and cephalopods (Figure below).
Does Mollusca have body cavity?
Both molluscs and annelids probably evolved from free-living flatworms. But molluscs have developed a true coelom, an internal body cavity enclosed by mesodermal membranes. The coelom in molluscs, however, is strangely reduced to a small space around the heart, sometimes called a hemocoel.
Why is Snail a Mollusca?
They have a mantle, and also have a shell for their protection. Their body is not segmented, and they are bilaterally symmetrical, and are coelomates. Snails come under the class gastropod. All of these morphological and anatomical traits put snails under the classification of a mollusc.
What type of body cavity do starfish have?
coelom
Do mollusks have brain?
Molluscs, with the exception of the most highly developed cephalopods, have no brain in the strict sense of the word. Instead, the cell bodies (pericarya) of nerve cells are concentrated in nerve knots (ganglia) in important parts of the body. Mollusc nerve cells have no myelin sheath.
What is the largest mollusc?
Reaching lengths of up to 4 feet and weighing more than 500 lbs., the largest living mollusk, and bivalve for that matter, is the giant clam (Tridacna gigas).
What is the biggest clam ever found?
Giant Clam facts
- The largest giant clam ever discovered measured 137 centimetres and weighed around 250kg!
- In centuries before, giant clams were nicknamed ‘man-eating’ clams, due to the belief that they ate divers whole!
- By day, giant clams open their shells so that the algae inside them get a chance to photosynthesise.
Do clams feel pain when opened?
Clams can clearly respond to certain stimulus, but whether or not that stimulus can create a feeling that we imagine as “pain” is unknown. This brings up the final question that most people have: Should people eat clams? Vegans and most vegetarians will say no, because clams are still animals and might feel pain.