03 May 2007

The Meaning Of The Rat and the Honeybee

One of the most important philosophical issues in environmental policy can be summed up in a small furry package called a Laotian rock rat (Laonastes aenigmamus), common name in Laos, Kha-nyou.

The Laotian rock rat, like a lot of notable endangered species, is a relict. It is the sole surviving species of a family of rodents that otherwise went extinct 11 million years ago, called Diatomyidae, it has an isolated geographic range, and it has only modest ecological importance.

If Colony Collapse Disorder wipes out the common honeybee, or the banana goes extinct (see Snopes for caveats), you and I will feel that ecological impact dramatically, it will interrupt the human food chain. In contrast, if the Laotian rock rat were to go extinct (who knows if it is endangered itself, it was rediscovered by Western scientists in 1996), it will slightly narrow the range of traditional delicacies available in Laotian street markets and few others will notice. International trade which provides new sources of food for Laotians is probably squeezing these markets economically in any case.

Mammals are one nineteen or so classes of animals in the phylum cordata which includes all vertebrates. Cordata is one of about 37 phyla of animals. The most abundant order of mammals is that of the rodents, which make up about 40% of all known mammal species, it is one of about nineteen orders of mammals.

So, our Laotian rock rat resurrects a new family within this Order. Previous analysis had given it a different place within the same suborder. In the mammal biology world, this is still a big thing. The last time before this that someone discovered a new family of mammals was when the bumblebee bat family was discovered in 1974. When a new or relict family of mammals gets discovered a couple of times every thirty years, we can pretty pretty comfortable that the gross outline of this part of the animal taxonomy is pretty close to accurate.

The Laotian rock rat is a tangible connection to a whole branch of evolutionary history. We can now make definitive statements about the DNA of the Diatomyidae family where previously we had only guesses based upon the closest living surviving relative, the African grundie, another kind of rodent. It can help us field test things like the pace at which evolution unfolds, information that could help corroborate other evolutionary issues like the link between the dinosaurs and the birds, a long hypothesized connection cemented when we learned that the closest living relative of T-Rex today is the chicken.

But, how do we weigh the importance of the rock rat and the honeybee? The rock rat is a sole species left of an entire family of animals. The honeybee, in contrast, is one species of a great many in its family. But, the rock rat is quite unimportant to other the larger web of life, while the honeybee is a lynch pin of the ecosystem.

Also, if we value relicts, should we value higher order relicts, like the tuatara, which are the sole representatives of a higher order of classification in the taxonomy more than we do lower order relicts, like the rock rat.

Most of the time, we don't have to weigh apples and oranges like rats and bees and bananas, but when legislators and the environmental protection agency set priorities in he midst of a massive, human caused extinction, which they have limited resources to address, it does matter.


Sotosoroto said...

We're living in a period of mass extinction that's been going on for thousands of years. How much is human-caused and how much is part of the natual cycle of life on this planet (cyclical extinctions caused by extra-galactic radiation?), I don't know.

But I do know that if the honeybees die off, humans will find ways to replace all their uses. We'll keep the orchards bearing fruit, etc.

And I also know that life will continue to exist on this planet even if humans die off. I just hope it doesn't happen anytime in the next billion years or so.

Andrew Oh-Willeke said...

FWIW, it feels much better to be disagree over the causation of a die off, than it does to try to talk sense with the folks that deny the existgence of evolution or recent extinctions.