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Breakthrough Gives 3-D Vision of Dawn of Life
butterwise writes "MSNBC reports that a new scanning technique could revolutionize paleontology. The new technique is allowing researchers a virtual dissection of half-billion-year-old fossilized embryos." From the article: "The Chinese, Swedish, Swiss and British researchers on Donoghue's team used a 1,640-foot-wide (500-meter-wide) particle accelerator in Switzerland to scan the minute fossils, and then fed the information into a computer that generated complete 3-D images of the internal structures in fine detail."
ancalagon by mike scholtes
In the lagan from Cambrian seas,
There's a dragon that's catching some z's.
Though ancalagon's gone,
Its priapulid spawn
Are still dodging extinction with ease.
(an-KAL-a-gon) A Cambrian priapulid (penis worm) found preserved in the Burgess Shale, ancalagon was apparently named after a dragon (Great Worm) in Tolkien's Lord of the Rings. Priapulids burrow tail-first into the sea floor with their mouth-parts exposed. A priapulid feeds by everting its gut, fastening onto soft-bodied prey, and then pulling gut and prey back down into its buried body. Lagan (sometimes spelled ligen or lagend) is a term from salvage law referring to goods that have sunk to the sea floor but are marked for recovery. Here it is metaphorically applied to fossils.
Man, you really need that seminar!
Tiny fossils are easy to get back to the lab, unlike, say, a multi-metre-long Tyrannosaurus rex, which takes a big excavation.
The 3D reconstruction of fossils isn't new. That's been done for, oh, probably close to 100 years. In the early 20th century, it was done by grinding down a fossil specimen millimetre by millimetre, sketching or photographing each surface, and then putting together a wax or paper model of each section until the 3D shape is reconstructed. It's been done for everything from fossil plants to fish and other vertebrates. Very laborious work.
More recently, people do the same thing, but take a digital picture of the sections and use software to assemble a 3D volume and select and render parts of it. If the object is relatively large (say, centimetres in size and larger), it can alternatively be subjected to medical CAT and other types of non-destructive 3D imaging techniques. This is routine for specimens such as dinosaur skulls, in order to see the interior without destroying the specimen. If the fossil is small and transparent, 3D imaging can be done with laser scanning confocal microscopy. But opaque, small (say, require the destructive serial sectioning method, meaning you have a nice, scientifically valuable 3D reconstruction at the end of the procedure, but no specimen anymore.
The new part in this technique is therefore the *non-destructive* 3D reconstruction of such tiny fossil specimens. That's where the particle accelerator becomes necessary to get sufficient resolution to be useful. This is much higher resolution than typical 3D medical imaging. The general technique isn't that unusual, because it has existed for years too. It is the application to microfossils that is relatively new (Nature registration required to view that last article).
Oh, and if people are wondering what "penis worms" are (the jokes are piling up by now), the technical term is Priapulida. More details at the linked page.
Yeah, I know. I'm spoiling the fun.
Well, what an imagination you have! What are *your* nanites built out of that they can slip between molecules without disturbing them...? (Hint: The next thing smaller than a molecule is an atom. Single atoms aren't nanites, and when you stick several together you have a molecule...)