a beautiful mathematical construct…
a reminder that we perceive beauty in the emergent patterns derived from simple iterative algorithms (shells, organic growth, life, culture, evolution)
The Wentletrap shell takes its name from a “spiral staircase” in German-Dutch, and it reminds me of the architecture of Gaudi
thanks… they are commonly called worm shells, but they are not made by worms.
I wonder if the repeated pattern comes from growth spurts between successive outer lip formations, inducing a spiral gap? In other words, when the snail grows a bit too big for its shell, does it quickly grow a new segment and smooth outer lip, and then stop shell growth for a while until the pattern repeats? If so, it might explain the wonderful air gap running along the entire spiral. A continuous growth process lends itself to a slanted and tightly wound spiral, methinks.
heet-myser: funny bait there… ’tis all in the eye of the beholder…. 😉
As usual google summons up poetry:
(1) Department of Theoretical Conchology, The Science-Art Centre, 2 Tern Place, 5019 Semaphore Park, South Australia, Australia
Received: 16 August 1988
Summary Unlike its predecessor this second paper formulates the problem of seashell geometry entirely in real spaceE 3, presenting those equations of most use for parctical digital computer similations. The mathematics dilates previously mentioned clockspring “wires” (growth trajectoriesY(ϕ)) into tubular spiral surfacesr(σ, ϕ) complete with orthoclinal growth lines and simple periodic corrugations or flaresQ(σ, ϕ). It is seen that second-order theory requires a new boundary condition, the famous HLOR growth vectorr(σ, 0), which is absent from classical analyses. Thus it is demonstrated that simple periodic surface features, of a kind occurring widely in nature, obey precise Cauchy boundary conditions which may be related to the quantized cyclicities of metabolic, and geophysical, rhythms associated with biological shell growth.
from:
http://www.springerlink.com/content/n4632jv32u2326rk/
I’m gonna use "cyclicities " in my next conversation 😉
gorgeous… but i’m glad i don’t presently sport a horny operculum….
this is just fascinating – trawling various sites about shell growth, piqued by your questions about growth spurts and those repeated ridges, it would seem that elongated conical shells result from a low rate of growth per revolution around the coiling axis, commonly found in calmer environments…
and this explains that the raised ribs or "varices" are records of a pause in the growth of the shell, as you basically correctly surmised, where each rib marks the outer lip of the shell at an earlier stage… and presumably, the pauses were significantly long enough for enough accumulation of calcium carbonate to fan out considerably before the subsequent growth burst, in turn being so pronounced that it generates a gap between the coils.
or is it just that the lip remains exposed long enough that it furls to a point perpendicular with the rest of the shell, as a result of the little blighter mooching around rocks or munching on sea anomones?
can anyone explain the cyclical trigger for such pauses / spurts? they appear to be incredibly regular. might it be related to solar or lunar cycles, quite apart from the metabolism of the mollusc itself?
on my travels, i found an amusing piece of Wikivandalism (look carefully) :
it seems that my task for tomorrow is to borrow D’Arcy Wentworth Thompson’s On Growth and Form from Glasgow Uni library 🙂
can always count on learning a thing or two when visiting your photostream…. who’d a thunk!
When I saw this pic a sec’ ago: http://www.flickr.com/photos/tracylee/2494655865/
I saw this of yours in my mental screen. 🙂
I wondered: is that other pic the inside view of this one… |-)
Actually, the varices are usually not associated with pauses in growth. What seems to occur is a change in the direction of precipitation of the calcium carbonate that composes the shell. Shell deposition is typically coplanar aperture (opening) of the shell, but at semi-regular intervals the mantle tissue that deposits the shell will deposit mineral almost perpendicular to the aperture. This can happen even while growth is continuous. The reasons for depositing a varix are probably related to the defensive nature of the structures, and will occur at regular intervals in order to maintain the overall defensive nature of the shell.
This is, btw, a beautiful photo!
A lot of shelled molluscs do this. It is frequently for anti-predatory purposes; varices effectively make the shell larger and more difficult to handle without requiring the animal itself to grow larger. In other instances, the varices can function as ratchets to aid in burrowing, or to prevent being scoured out of the sediment. Jurvestson’s caption is correct, in that algorithms for describing this type of growth can be surprisingly simple. But how does the animal know when to deposit a new varix? 🙂
Great environmental shot and a wonderful thought
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Seen in The World Through My Eyes – Post 1 / Comment Any 1 (?)
Hi, I’m an admin for a group called *PIG Awards* – Post 1- Awards & Fave 3, and we’d love to have this added to the group!
Carleton, so it looks like, but we are used to those groups already. My comment was for the name, and the uhm, icon (or is that the award directly?)… you never know what they come up with! Don’t cease to surprise me.
Heart shaped bubbles are cool, tho, aren’t they? 😀
wow!! mother nature is a fantastic artist!!!
PIG Awards!!!
Seen in:
PIG Awards!!!
Natural Patterns, Shapes, and Textures
I think this photo would make a great addition to the Natural Patterns, Shapes, and Textures (moderated) group. Please consider posting it there!
Wonderful, absolutely brilliant – lovely colours, great perspective and excellent composition
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