Then don’t read about hyena births. Puppies ripping their way through clitorises does not make a pretty picture.
Pharyngula
Evolution, development, and random biological ejaculations from a godless liberal
Then don’t read about hyena births. Puppies ripping their way through clitorises does not make a pretty picture.
Lisa Jardine is a historian who clearly understands how science works:
The thought uppermost in my mind was how odd it is that non-scientists think of science as being about certainties and absolute truth. Whereas scientists are actually quite tentative—they simply try to arrive at the best fit between the experimental findings so far and a general principle.
Read the rest. She ties together the ideals of how science should be carried out with a story from Pepys and an unscrupulous sea captain and modern day creationists—excellent stuff!
How else can you explain why those adorable screaming moonbats at the Daily Kos have come up with a science book? I’m kind of dismayed that good science has become a partisan issue, but don’t blame us—our side puts out stuff like Kosmos: You Are Here, while the righties seem to have a surfeit of Lotts and Bethells.
In previous articles about fly development, I’d gone from the maternal gradient to genes that are expressed in alternating stripes (pair-rule genes), and mentioned some genes (the segment polarity genes) that are expressed in every segment. The end result is the development of a segmented animal: one made up of a repeated series of morphological modules, all the same.
Building an animal with repeated elements like that is a wonderfully versatile strategy for making an organism larger without making it too much more complicated, but it’s not the whole story. Just repeating the same bits over and over again is a way to make a generic wormlike thing—a tapeworm, for instance—but even tapeworms may need to specialize certain individual segments for specific functions. At its simplest, it may be necessary to modify one end for feeding, and the opposite end for mating. So now, in addition to staking out the tissues of the embryo as belonging to discrete segments, we also need a mechanism that says “build mouthparts here (and not everywhere)”, and “put genitalia here (not over there)”.
This strange fish is Euphanerops longaevus, which is one of two species of 370 million year old jawless fishes (the other is Endeiolepis aneri, and the paper suggests that they may actually represent differently preserved members of the same species). These are soft-bodied animals that are usually poorly preserved, and are of interest because they seem to have some properties in common with both the lampreys and the gnathostomes, or jawed fishes. Their exact position in the vertebrate family tree is problematic, and the experts go back and forth on it; sometimes they are grouped with the lampreys, sometimes as cousins more closely related to the gnathostomes.
Paul Nelson has been twittering about ORFans for some time now—he seems to precede his talks by threatening to make us evolutionists tremble in our boots by bringing them up, but he never seems to follow through. Ian Musgrave got tired of waiting for him to give us a coherent creationist argument about them, and has gone ahead and cut him off at the knees by explaining the place of ORFans in evolution.
In case you’re baffled by the jargon, “ORF” is an Open Reading Frame, or a stretch of DNA bracketed by a start and stop codon; it’s a kind of bare minimum criterion for recognizing an actual gene within a DNA sequence. An ORFan is an orphan ORF sequence, or one that doesn’t have a known function or affinity to other known genes. It is not surprising that genes exist that do not have an easily recognized homology with other genes—novel genes have to arise sometime, and we do not have a complete understanding of all sequences of all organisms.
The short answer is that Nelson is deluded, and ORFans do not conflict with evolution at all…but read Ian’s post for all the details.
The latest edition of the Tangled Bank is coming straight to you from Coruscant…and the opening text is almost as long as the latest from Lucas, although fortunately it doesn’t say anything about the trade federation and boring treaties.
This really is an excellent review of three books in the field of evo-devo—
From DNA to Diversity: Molecular Genetics and the Evolution of Animal Design (amzn/b&n/abe/pwll),
Endless Forms Most Beautiful: The New Science of Evo Devo and the Making of the Animal Kingdom (amzn/b&n/abe/pwll), and
The Plausibility of Life:Resolving Darwin’s Dilemma (amzn/b&n/abe/pwll)—all highly recommended by me and the NY Times. The nice thing about this review, too, is that it gives a short summary of the field and its growing importance.
We’re having our last Café Scientifique Morris of the 2005-2006 school year tonight, at 6:00, at the Common Cup Coffeehouse here in beautiful downtown Morris, Minnesota. Our speaker is Mark Logan of the Mathematics discipline, who’s going to be talking about “Origami in Math and Science”—that wonderful interdisciplinary stuff we liberal arts colleges do so well, tying together math and art.
It’s a good thing we’re doing it tonight so that we don’t suck away Sean Carroll’s audience for the Café Scientifique Chicago tomorrow.
Sciencebase has a short article on a potential new aphrodisiac. It’s called PT-141, or bremelanotide, or Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH (“PT-141” is the useful search term if you want to hit up PubMed), and it’s a melanocortin agonist that works directly on the brain. It can be delivered as a nasal spray. It works on men, promoting erections, and it also seems to be effective on women, increasing sexual appetite.
