There is now a web page dedicated to the Neoceratodus cause. If you haven’t yet fired off a letter to oppose the destruction of the lungfish’s habitat, there’s a sample letter there to help you get started. It’s not too late to make your voice heard!
Carel Brest van Kempen has posted one of his paintings of Cambrian animals—be sure to click on it to get the larger size. I wish I had a pet anomalocarid in my aquarium.
Assuming that none of my readers are perfectly spherical, you all possess notable asymmetries—your top half is different from your bottom half, and your front or ventral half is different from you back or dorsal half. You left and right halves are probably superficially somewhat similar, but internally your organs are arranged in lopsided ways. Even so, the asymmetries are relatively specific: you aren’t quite like that Volvox to the right, a ball of cells with specializations scattered randomly within. People predictably have heads on top, eyes in front, arms and legs in useful locations. This is a key feature of development, one so familiar that we take it for granted.
I’d go so far as to suggest that one of the most important events in our evolutionary history was the basic one of taking a symmetrical ball of cells and imposing on it a coordinate system, creating positional information that allowed cells to have specific identities in particular places in the embryo. When the first multicellular colony of identical cells set aside a particular patch of cells to carry out a particular function, say putting one small subset in charge of reproduction, that asymmetry became an anchor point for establishing polarity. If cells could then determine how far away they were from that primitive gonad, evolution could start shaping function by position—maybe cells far away from the gonad could be dedicated to feeding, cells in between to transport, etc., and a specialized multicellular organism could emerge. Those patterns are determined by interactions between genes, and we can try to unravel the evolutionary history of asymmetry with comparative studies of regulatory molecules in early development.
Muton has some splendid photos of fossil spiders.
Since I shared one paper describing how cephalopods attack, here’s another showing step two: what to do with your prey once it is snared by your suckered limbs. Here’s a sampling from a video sequence of an octopus reaching out to grab some food and bring it back to the mouth:
If anyone is interested in writing a Lovecraftian horror novel and getting all the details just right, I recommend this paper by Kier and Leeuwen. They used a high-speed camera to capture exactly how a squid, Loligo pealei, strikes and seizes its prey. Isn’t it beautiful?
I got a request to help identify this bizarre creature. I’m guessing it’s a slug caterpillar, from the family Limacodidae, although I couldn’t possibly narrow it down further, and could be completely wrong. Whoever was filming it can be heard telling someone not to touch it—which is a good idea. These things shed fine hairs that can cause a painful allergic rash.
It’s kind of cute, anyway.
I think the collective wisdom of the internets has convinced me that it is a puss caterpillar, Megalopyge opercularis.
People, scientists included, are always looking for simple, comprehensible explanations for complex phenomena. It’s so satisfying to be able to easily explain something in a sound bite, and sound bites are so much more easily accepted by an audience than some elaborate, difficult collection of details. For example, we often hear homosexual behavior reduced to being a “choice,” the product of a “gay gene,” a “sin,” or something similarly absolute and irreducible…suggesting that it is part of a diverse spectrum of sexual behaviors with multiple causes and that different individuals are different in their behaviors is almost certainly the more accurate description, but that doesn’t satisfy our need for straight, simple, linear causal mechanisms. This is true of most animal behavior, I think—you just can’t crunch it down to one single agent that drives much of anything.
I thought there was one excellent counter-example, though, one that suggested at least some complex behaviors might be reducible to a discrete source: the mating behavior of Microtus voles. It was such a simple, clean story; new results suggest that it was too clean, and that there’s much more to the behavior than was thought.
Yunnanozoans and Xidazoon…there are some very pretty early Cambrian critters on display at Sinanthropus.
