Busy week

I thought I’d be skipping my Pilates method class to go to the FrameMaker Users’ Network; but now it looks as if I’ll be skipping it to go to dinner with some Famous Sciencebloggers. But I can do the Pilates class on Thursday.

Virgin birth in hammerhead shark

In 2001, a hammerhead shark in a zoo in Omaha Nebraska gave birth to a ahark pup. Unfortunately, the pup was killed by a stingray within hours. The three female sharks in a mixed tank had been separated from male hammerhead sharks for three years and had arrived as immature pups themselves.

Research into this curiosity has shown that the shark pup’s DNA all came from its mother; no males were involved. This is the first known case of parthenogenesis in sharks.

Asexual reproduction is common in some insect species, rarer in reptiles and fish, and has never been documented in mammals. The list of animals documented as capable of the feat has grown as more are raised in captivity — but until now, sharks were not considered a likely candidate.

Is this evidence that the Bible is TRUE? Is God smiling on Nebraska? Or does it have something to do with that business trip LotStreetWiz took to Nebraska around that time? (If Algis Budrys could make Spider Robinson’s goldfish pregnant…) However, it’s unlikely that the Virgin Mary became parthenogenetic: it seems to happen only in the absence of males.

Before the study, many shark experts had presumed that the Nebraska birth involved a female shark’s well-documented ability to store sperm for months. This seemed the most plausible scenario even though the sharks had arrived at the Nebraska zoo as immature pups.

Parthenogenesis is a way of squeaking through the slimmest of all evolutionary bottlenecks: one single female.

“This phenomenon has now been demonstrated in all major vertebrate groups except for mammals. Birds do it, reptiles do it, amphibians do it, fishes do it and now sharks are known to do it,” said Bob Hueter, director of the Center for Shark Research at the Mote Marine Laboratory in Sarasota, Fla., who was not involved in the project.But Hueter said he doubted it was happening anywhere besides in captivity. He also argued that the power to self-impregnate represents “an evolutionary strategy to keep the population and species going when all else fails.”

Genetically, it’s a last-resort tactic because it leads to genetic uniformity, and eventually that will catch up with the population and make it less fit.

“But as a short-term alternative to extinction, it has its benefits,” he said.

Guppies have a different strategy: if all males are removed from their environment, the most dominant female becomes a “male” and mates with the females.

Dawkins is tops at The Hour

Richard Dawkins was recently interviewed at CBC’s TV news show The Hour, talking with George Stromboulopolos. That interview is currently the most popular for the show, with more than 28,000 views of the video. The next most popular, some babe, has about 5,700. (See the left sidebar.) You can click on the picture of Dawkins to play it. Mind you, The Amazing Kreskin is fourth and coming up fast.

Christopher Hitchens is scheduled for an interview, but I don’t yet know when.

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