Jeopardy! category: ANATOMICAL ETYMOLOGY (12-11-2014)
Daily Double! $1200 clue: Used as a synonym for thorn, this structure’s name comes from a Latin word for “thorn”
The gist: We humans only have one of them, but other creatures can have many more. Our spine is, of course, our backbone, also known as the “vertebral column” as it usually consists of 24 articulated vertebrae* in adults (individual mileage may vary) that surround and support the spinal cord, plus nine more that are fused together to form the sacrum and the coccyx (aka the tailbone). Our wonderful if sometimes troublesome backbones evolved from very ancient structures known as notochords, thin rod-like structures that run lengthwise along the middle of all members of the phylum Chordata. Notochords first developed well over 500 million years ago (some estimates put the figure at almost a billion) in a group of worm-like critters known as deuterostomes, of which today’s sea cucumbers are members. In most modern Chordata the notochord, present in early stages of embryonic development, turns into the innermost part of the intervertebral discs that lie (duh) between the vertebrae, but some primitive organisms, like hagfish, lampreys, and the famous “living fossil” coelacanth, retain their notochords into maturity.
But then there are those lucky animals who have those other sorts of spines: big, menacing spikes that jut out from their bodies and poke at anyone foolish enough to bother them. In mammals like porcupines, hedgehogs, and echidnas, spines are generally modified hair follicles that have become thicker, more rigid, and pointier at the ends – though none can “shoot” their spines as the popularly-held belief about porcupines claims, some are able to dislodge their spines so they stick in attackers. In fish, spines are generally bony structures, usually developing from the bony protrusions that support the fins. Stingray barbs are also often called spines, although they are homologous with vertebrate teeth, not bone. In invertebrates, like sea urchins and several molluscs, they are structures of the shell, and so composed of calcium carbonate.
As for why pointy things and backbones share the word “spine,” I’ll be honest – all the etymological resources I consulted, including the Oxford English Dictionary and EtymOnline, didn’t really say. EtymOnline indicates that the sense of backbone was around a little before the pointy thing, although not by much so I’m not entirely convinced that should be taken as a safe conclusion. If I were to guess, I’d say there are two likely reasons: 1) many vertebrae, including human vertebrae, have pointy protrusions coming out the back of them known as “processes” that make them look sort “spiky,” or 2) as the spines on, say, a porcupine are rigid and stand straight, so the spine stays rigid and keeps us upright, or generally keeps the body of an animal “straight.” If anyone has more information on this, I’d love for you to leave it in a comment.
The clue: This one’s a thinker, and, as befits a Daily Double!, has a couple tacks one can take to it. Do you begin by thinking of synonyms for “thorn” (spike, barb, prickle, quill…), or do you begin by thinking of a structure that might have something to do with a thorn? Unfortunately, I think contestant Jim took the second route, and ended up half-heartedly guessing “thumb.” I suspect that working from “thorn” would be easier in this case, especially because I doubt most people would associate the spine with thorns, despite the “thorny” projections on many of our vertebrae.
In Jeopardy!: “Spine” is in too many clues in the J!Archive to easily analyze, including as a part of some longer words (like “spinet,” a type of small piano). But, a couple patterns to jump out: it’s often used as a synonym for bravery or courage, or in “spineless” as an antonym, vertebrae are often mentioned (of course), and it’s much more often int he clue itself than it is the correct response (more than five times more often). Remember the types of vertebrae, and keep it in mind for wordplay categories, particularly when they’re anatomically-themed.
*For the truly trivia-minded: 7 cervical vertebrae, 12 thoracic, 5 lumbar; 5 fuse to make the sacrum, and 3, 4, or 5, depending on genetics, to make the coccyx.