(from this very strange and to me, unreadable page)
Pharyngula
Evolution, development, and random biological ejaculations from a godless liberal
Whoa, it’s been a while since I’ve said anything about my infatuation with cephalopods (since, like, the last post…). Let’s correct that with a nifty paper I found on octopus suckers.
Here’s a typical view of a tangle of octopus arms, all covered with circular suckers. The octopus can cling to things, grasp prey and other objects with those nifty little discs, and just generally populate people’s nightmares with the idea of all those grappling, clutching, leech-like appendages.
Hmmm…this video of an octopus attacking a man looks as phony as the battle between Bela Lugosi and the rubber octopus in Bride of the Monster to me. It makes for an entertaining break in the grading slog I’m in right now, but it would have been much improved if the octopus had won.
(via Phil)
Ooooh, what lovely fun: it’s a short photoessay of a squid dissection. I think the photo of the gut contents ought to be made available in a much larger size so it can be used as a desktop image, though.
This one is for those blood-thirsty free-riding sprogs.
Figure from Cephalopods: A World Guide (amzn/b&n/abe/pwll), by Mark Norman.
Crap. Coturnix tagged me with this beautiful bird meme, and I am the wrong person to ask. I don’t get out much, preferring to sit in the lab or the library, so my favorite birds are all in pieces and dead. But OK, since he asked…
Bird digits
Bird teeth
Bird brains
Jurassic bird brains
Bird lungs
Oviraptor pelves (does that count?)
Cretaceous bird embryos
Four-winged birds
Waimanu
And Archaeopteryx, of course.
Diploblasts are popping up everywhere this week. If you take a look at the phylogeny in this article, you’ll see that one of the diagnostic features of the cnidarians is the presence of the cnidoblast, which contains a stinging nematocyst. This is the ‘stinger’ of the jellyfish…and now it’s been caught on video. It’s very cool—watch the movie!
The Wnt genes produce signalling proteins that play important roles in early development, regulating cell proliferation, differentiation and migration. It’s hugely important, used in everything from early axis specification in the embryo to fine-tuning axon pathfinding in the nervous system. The way they work is that the Wnt proteins are secreted by cells, and they then bind to receptors on other cells (one receptor is named Frizzled, and others are LRP-5 and 6), which then, by a chain of cytoplasmic signalling events, removes β-catenin from a degradation pathway and promotes its import into the nucleus, where it can modify patterns of gene expression. This cascade can also interact with the cytoskeleton and trigger changes in cell migration and cell adhesion. The diagram below illustrates the molecular aspects of its function.
