Thursday, November 17, 2016

The Word "Worm"

It's no secret that I think common names are a problem.  They would be great if they were as systematized as scientific names but that's simply not the way language works.  Common names are a product of colloquial, everyday speak and therefore they are the antithesis of scientific names.  They lead to situations where we have a blue crab, a lesser blue crab, a red blue crab (seriously!?) and an ornate blue crab all inside the same genus.  Common names give us such taxonomically frustrating linguistics as the electric eel (a knifefish more closely related to catfish than eels), the bearcat (something like a civet), and the flying lemur (in a branch of mammals separate from all the primates).  

It also creates situations like when I get a video of some insects milling around on top of a tidal pool from a friend, she asks what they are, and I reply "Anurida maritima," and there is no common name.  The fact that we typically understand organisms only through their common names means that when we're faced with a situation when an organism doesn't have a common name we don't have the hooks to hang new information on much of the time.  I'm not suggesting we give up on common names, again, they are part of colloquial language and you cannot stop the indomitable force that is the evolution of language.  But there's one name that's always deeply frustrated me: "worm."

If you use the word "worm," people typically think of an earth worm, which is a land-living oligochaete in the phylum annelid, one of the closest living families to the arthropods.  But when you bust out a list (I got on this rant when I was once in a middle school science room and saw a poster of major animal phyla) of all animal phyla you start to see how little this name means: spiny headed worms, Acoelomorpha, segmented worms (Annelid), arrow worms, goblet worms, gastrotrichs ("worm-like"), jaw worms, acorn worms and roundworms, horsehair worms, ribbon worms, flatworms, peanut worms strange worms, velvet worms.  The number varies from source to source and also starts to get even more garbled when you descend to the subphylum and lower levels.  

So what, then, is a worm?  Etymologically speaking the word comes form the Latin "vermis:" vermin.  This is a great colloquial word with no real scientific meaning.  It's kind of like...anything gross or small so flies, maggots, earth worms, but even rats and snakes can be vermin.  Moving forward into Middle English you get "wyrm" which means a snake or a worm (and as I hope you all know, a snake is not a worm).  When you start poking around in other languages "wyrm" sometimes means "dragon" as well.  

So biologically what is a worm?  Well, the online OED says that a "worm" is "Any of a number of creeping or burrowing invertebrate animals with long, slender soft bodies and no limbs."  That is basically it, except for Onycophora, which does have limbs.  But we get to call anything that is bilaterally symmetrical and longer than wide a "worm."  Which is, as we've seen, a huge chunk of the animal world.  

So I'm not suggesting we get rid of the word.  But next time you call something a "worm," maybe remember how unspecific the word really is.