Friday, May 25, 2007
Josh's New and Hot (Week 9) + Book Review
In a very bizarre news story, scientists have confirmed that a female hammerhead shark at the Henry Doorly Zoo in Nebraska has reproduced by parthenogenesis, meaning that is reproduced ASEXUALLY! Although this escapade began in 2001 with the seemingly virgin birth of a pup that was, unfortunately, immediately bitten to death by a stingray, it is only now that new DNA profiling techniques that have allowed scientists to say definitively that this was done without the assistance of a male. This was also anecdotally confirmed when all three female sharks were found without bite marks - a hallmark of shark sex.
Scientists are attributing this phenomenon to the extreme pressure of finding a mate among the sharks. It it seems that the population is so overfished that the female will often go so far as to leave out the role of the male. This occurrence is rare in vertebrates, but occurs regularly in some insects like bees and ants who use it to create more drones. That said, a case similar to this was reported Winter of 2006 when a Komodo dragon of Chester Zoo was found to also have had a virgin birth experience. In a poetic touch of nature, her eggs hatched very close to Christmas.
While this may seem like a very cool thing for perpetuating a species that is becoming increasingly endangered, Darwin and evolutionary biologists would says otherwise. By not reproducing with males, the independent females are reducing the genetic diversity of their offspring. This denies their offspring potential traits that may make them more fit to deal with changing environmental conditions. Zoos are now recommending that animals that have the potential to reproduce parthenogenically be kept in captivity with members of the opposite gender to ensure the opportunity for sexual interaction.
I think Stanford addressed this years ago by creating coed housing. Three cheers for biodiversity!
By the way, check out my Amazon Review of God Delusion.