The latest in Pharyngula-approved carnivals:
Now, open that thread and sing!
Palaeos is gone! There is a brief note about being unable to support it any longer, and then poof, it’s offline. Martin Brazeau has a comment on it’s value; you can still see fragments of this great resource in google’s cache, but even that will fade too soon.
This is troubling, and it’s one of the worrisome aspects of using the net—there’s no sense of permanence. It would be good if someone were to step forward and at least archive all of the pages, but the essential feature of the Palaeos site was that it was continually maintained and updated to reflect current information, and that’s not something that can be supported without the dedication of much time and effort by someone knowledgeable in the subject.
Next time you’re cutting up a fresh bird, try looking for the lungs. They’re about where you’d expect them to be, but they’re nestled up dorsally against the ribs and vertebrae, and they’re surprisingly small. If you think about it, the the thorax of a bird is a fairly rigid box, with that large sternal keel up front and short ribs—it’s a wonder that they are able to get enough air from those tiny organs with relatively little capability for expanding and contracting the chest.
How they do it is an amazing story. Birds have a radically effective respiratory system that works rather differently than ours, with multiple adaptations working together to improve their ability to take in oxygen. There is also a growing body of evidence that dinosaurs also shared many of these adaptations, tightening their link to birds and also making them potentially even more fierce—they were big, they were active, and their lungs were turbocharged.
I’ve been a bit sex-obsessed lately. No, no, not that way—it’s all innocent, and the objects of my obsessions are all fish.
A little background explanation: one of my current research projects is on the genetics of behavior. This is a difficult area, because behavior is incredibly complex with multiple levels of causation, and one has to be very careful when trying to tease apart all the tangled factors that contribute to it. It takes numbers and lots of controls to sort out the various contributors to a behavior.
Zimmer has a summary of the latest discoveries in the evolution of the baleen whales. It’s beautiful stuff, with the lineage showing their origin from toothed whales, through a phase where they had both teeth and baleen, to their current condition lacking teeth and having only baleen.
Awww, it’s a charming little story about the intelligence of the octopus:
Ah, the creepy-crawly creature, the swarming arms, that deep-sea demeanor. This is the bearer of intelligence?
“That was my attitude, too,” confesses science writer Eugene Linden, who has written about animal intelligence since the 1970s and had focused, mostly, on the “big-brained” creatures such as apes, dolphins, elephants and whales. “I shared all the prejudices everybody else has.”
Then he started hearing octopus stories. Like how they can open screw-top jars and hamster balls and child-proof caps. They can do mazes and learn shapes and distinguish colors and use tools.
“They play,” says Jennifer Mather, a psychologist and octopus expert at Canada’s University of Lethbridge.
There are even hints that octopuses have a sense of humor, Linden says.
He talks about the finicky octopus who, in a lab in Pennsylvania, was served slightly spoiled shrimp. The octopus refused to finish its dinner, and when the feeding researcher returned to its tank, the octopus made eye contact with her, then meaningfully pushed all the shrimp down the drain.
A great deal of that is the interpretation of the human observer, of course; it could be the octopus isn’t making a joke at all, but is instead mentally noting the face of the offending person and promising itself to make her pay someday. But still, it’s clear that some wonderfully sophisticated things are going on inside those big invertebrate brains.
(Thanks to Mrs Coulter)
A reader sent in a question asking me to explain this: a swallowtail wings with different color patterns. Has anybody seen anything like this before? Got any explanations?
My first thought was that it was a genetic mosaic. A mitotic error in early development can lead to one wing primordium carrying a mutant allele, and the other carrying a wild-type form. At metamorphosis, the differences would become visible. It could be a defect that knocks out one pigment on pale wing, or since swallowtails can show sexual and seasonal dimorphism, it could be a change that switches on or off a male/female pattern, or an early summer/late summer pattern. Alternatively (and probably less likely), since seasonal morphs are switched by environmental conditions, this could have been a pupa in a very odd place that got different signals on the two sides.
If you’ve got a better idea, pass it on in the comments.
Surely, you haven’t had enough information about pycnogonids yet, have you? Here’s another species, Tanystylum bealensis, collected off the British Columbian coast. That’s a ventral view of the male, and those bunches of grapes everywhere are eggs and babies—males do the childcare in this group. These animals also live in relatively shallow water, in the lower intertidal zone, so it was possible to collect thousands of them and develop a complete staging series. Below the fold I’ve put some illustrations of the larvae, which are even cuter.
Pycnogonids really are fascinating animals and they deserve more attention. There’s a short news article on sea spiders that mentions their odd life style and their taxonomic awkwardness.
For over 100 years, scientists have been puzzling over how exactly to classify sea spiders or pycnogonids.
They crawl along the bottom of the sea floor, sometimes more than 6000 to 7000 metres down, where they live in the dark, feeding on slow-moving soft-bodied sponges and sea slugs.
The creatures are segmented and have an exoskeleton, which makes them an arthropod, the same grouping as crustaceans, insects, centipedes and spiders.
But they also have a very strange collection of features, including a unique feeding structure.
“They have a proboscis that’s like a straw that they insert into the animals and suck out the juices,” says Arango.
Such features make it difficult to fit them into any of the known groups of arthropods.
“They look like spiders, but they are not real spiders,” says Arango. “It’s been very hard to place them in a position within the tree of life.”
They really are hard to place—I’ve reviewed two articles on that subject, one that places them with the anomalocarids and another that groups them more conventionally, with the chelicerates (I’m going with that last one right now—patterns of Hox expression trump interpretations of innervation patterns, I think.)
There’s an offshore show I’d like to catch.
