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If there’s a case to be made for intelligent design, we’re not sure it should begin with the spiny dogfish. The fact is, their reproductive acts are nothing short of disturbing. If you’re up for the nature’s greatest argument for faking headaches, read on.
To conceive, the male grasps the female’s fins with his mouth and uses his two reproductive organs, known as claspers, to get the female pregnant. But this is no gentle act of foreplay. The sharp claspers leave deep cuts and gashes behind the female’s head, which take a week or so to heal. Once that’s over, the female has a glorious 22 to 24 months of pregnancy to look forward to—the longest gestation period of any vertebrate. And when the magical day finally arrives, you’d better believe she’s wondering where the heck her epidural is. Spiny dogfish mommies give birth to as many as eleven 3-ft long pups, each coming out head first. And while evolution has equipped the pups with cartilaginous sheaths on their spines to protect the mother from (further) injury, it still hardly sounds pleasant.
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Why should intelligent design not begin here? I don’t quite understand why that statement’s there…
re-captcha: ambition ing
posted by DYMongoose on 8-5-2008 at 11:59 am
@DYMongoose:
wikipedia says, “The stated purpose of intelligent design is to investigate whether or not existing empirical evidence implies that life on Earth must have been designed by an intelligent agent or agents”
Basically it says that, because life on Earth is so complex, so well-designed, and so intelligently made, that it is obviously the work of some sort of intelligent creator(s); it’s too good to simply be attributable to evolution, natural selection, etc.
I believe the author is saying that, since this fish’s mating and birthing processes are so painful and potentially life-threatening, this fish is NOT a good example in the argument for intelligent design.
posted by caitlen315 on 8-5-2008 at 12:23 pm
Oh dear, oh dear.
How awkward.
posted by Cassi on 8-5-2008 at 12:51 pm
apparantly i need to catch up on my biology… i thought fish laid eggs?
posted by tiffany on 8-5-2008 at 2:11 pm
@tiffany – that thought didn’t even occur to me.
“Ovoviviparous animals develop within eggs that remain within the mother’s body up until they hatch or are about to hatch. This strategy of birth is known as ovoviviparity. It is similar to vivipary in that the embryo develops within the mother’s body. Unlike the embryos of viviparous species, ovoviviparous embryos are nourished by the egg yolk rather than by the mother’s body. However, the mother’s body does provide gas exchange.
Ovoviviparity is employed by many aquatic life forms such as fish and some sharks, reptiles, and invertebrates. The young of ovoviviparous amphibians are sometimes born as larvae, and undergo metamorphosis outside the body of the mother.”
i heart teh interwebs. :)
posted by caitlen315 on 8-5-2008 at 2:33 pm
good to know. thank you caitlen!
posted by tiffany on 8-5-2008 at 5:10 pm
Wow. Crazy stuff. I’m quite glad humans have a different method.
I’m not sure this would be a great place to start arguing evolution theory either. You would think that in the course of however many millions of years you think the dogfish has been around, they would have evolved something a bit better, right?
posted by kate on 8-5-2008 at 7:43 pm
Evolution only cares about reproduction. If there was something about this process that caused the mother fish to never want to mate again, they would have died out. Apparently it’s not that bad or she’s not that smart. Or both.
Then again, by bearing that many pups, the survival of the species may not rest on her going through it more than once.
posted by Miss Cellania on 8-6-2008 at 8:17 am
Seems like a worse argument for evolution. Things that are detrimental to and threaten reproduction are generally weeded out through natural selection. So if this is so detrimental, why is it still happening? Perhaps it is not detrimental after all, but essential in some way to the reproduction process? Who knows, perhaps the dogfish’s immune system rises to protect itself from potential infection in the cuts, allowing it to be healthier during time of gestation? Just because we don’t know why an organism acts or reacts in certain circumstances doesn’t mean it is just a random happening. This is why we have scientists, to study the observed activity, and develop the most accurate interpretation of the why.
By the way, believe it or not, creation scientists and Intelligent Design theorists accept Natural Selection as an observable fact. It is the ultimate origin of the information inherent in our DNA, etc that is in question by ID theories. Creation Science of course attributes the source of information to God. ID recognizes that there might be a possibility of some organizational force at work greater than random chance that has instilled this information.
Science has yet to provide evidence that shows a mutation, breeding result, or any other Natural Selection method that clearly introduces new information into DNA. Natural Selection “selects” among genes already present that allow organisms to survive. Natural Selection either shuffles current genes around to allow for adaptation, or eliminates genes that are detrimental by circumstance. This can generate new ” species” by definition, but all of the varied species of Feline are still Feline and can clearly be demonstrated to have descended from a Feline ancestor. Their genes have been reshuffled and sorted, but never been “re-coded” as far as any hard evidence has ever shown.
posted by Jeremy on 8-7-2008 at 2:53 pm