Air Date: Week of August 17, 2007
The system we use to organize life is based on the work of the 18th century Swedish botanist Carl Linnaeus. But new tools, like DNA analysis, are giving modern taxonomists information about species that Linnaeus would never have dreamed of. Now, a group of scientists are suggesting that it's time to ditch the old organization of Kingdom, Phylum, Class, Order, Family, Genus, Species. Living on Earth's Ian Gray reports.
CURWOOD: Everything in nature has its place: Kingdom, Phylum, Class, Order, Family, Genus, Species. We can thank Swedish biologist Carl Linnaeus for the organization of our naming system. But now, 300 years after the birth of Linnaeus, new tools in DNA analysis are shaking up the tree of life. Things we thought were on one branch seem to fit better on another. And moving them gets a bit messy when a naming system is hierarchical. So some scientists think it's time for an update of the Linnean system of nomenclature. Living on Earth’s Ian Gray has our story.
[CLAP OF THUNDER]
GRAY: When I first heard someone was thinking of changing the way everything in nature is named, I thought the world would collapse into a fiery ball of chaos. The first person I thought of was my 7th grade science teacher Mr. Uecker.
GRAY: Do you remember when we learned about the tree of life?
UECKER: Uh huh. You’d use mnemonics. Kingdom, Phylum, Class, Order Family Genus Species instead of learning that you’d learn some tricky little sentence that would go with it, such as…King Philip… something about fried green spinach.
GRAY: Yeah, the one I really remember is that ‘King Philip Came Over for Green Spinach.’
UECKER: Came over for green spinach. Yeah, that was one. And the weirder it got, the easier it was for you guys to remember.
GRAY: Anyway this whole King Philip thing was a total revelation for me. I mean you got the whole structure of life in a single sentence. But how did we get that structure in the first place?
BARRIE: Linnaeus was born in 1707 and at that time, the botanists that were working in Europe all communicated in Latin.
GRAY: That’s Fred Barrie, botanist with the Missouri Botanical Garden and a Linnaean nut.
BARRIE: And at the time, the name for a species would have been a genus name plus a descriptive phrase. I can give you an example of one if you like?
GRAY: Sure. Why don’t you…
ANGRY EDITOR: Ian, you’ve got to get out the studio we have an editorial meeting now.
GRAY: Um…can’t you see I’m in the middle of an interview?
ANGRY EDITOR: Yeah, sorry too bad. Gotta get out, we gotta go.
GRAY: Okay, sorry about this, hey Gurgi?
GRAY: Can you fill in here for a second. We were just about to hear from Dr. Barrie how confusing animal and plant names were before Linneaeus came along.
GURGI: No Problem, I take over.
BARRIE: If you look at bananas,
GURGI: Yummm bananas!!!
BARRIE: The correct scientific name for a banana today is musa paradisica.
BARRIE: Bowhein from the 16th century called it Feicus indica fructa recimo folio oblongo.
BARRIE: Linnnaeus originally called it musa cliffordiana. But then changes his mind and calls it Musa recimo simplicimo.
BARRIE: And Musa spatami nutantae.
GURGI: Ahhh…Ian, Help!
GRAY: OK Gurgi. Sorry about that, okay I’m back. Here’s how Linnaeus fixed this taxonomic tangle. When he was putting together his famous book on plants he scribbled in the margins a single Latin noun to help him remember each species. When his book published, people realized these margin notes were easier to remember than the actual species name.
BARRIE: And it caught on very quickly, within two years people were publishing using this system, using this binomial system.
GRAY: So, Linnaeus, almost by accident, made it easy for people to talk to each other about how species are related. And now that system is well, law.
EGGLETON: There are rules for how you name animals and these rules are all written down in a nice red book.
GRAY: That’s Paul Eggleton.
EGGLETON: I work at the Natural History in London and I’m a specialist on termites.
GRAY: And he’s a fan of the this red book called, the International Code of Zoological Nomenclature. It governs how groups of organisms are named. But Eggleton’s crew recently caused a stir with a discovery about termites.
EGGLETON: Well, for a long time it’s been known that their closest relatives are praying mantises and cockroaches. But it turns out that as more information has come in, especially as we’ve started to use DNA in these analyses, we’ve now begun to realize that termites are nested within cockroaches, that they’re actually social cockroaches.
GRAY: Turns out this is something of a bummer for the termites.
EGGLETON: To go from an Order to a Family is a considerable demotion for a group.
GRAY: But it gets worse for termites. According to the red book, since termites are no longer at the Order level of the tree, they have to lose their Order level name—Isoptera. The code works like this: all Order level names end with the suffix “a”: Hymenoptera – the ants, Coleoptera – the beetles, Blattodea – the cockroaches etc. Family level names end with d-a-e…dae. So for the newly demoted termites…
EGGLETON: What they become instead of being the Isoptera they become the Termitidae, which is the correct form of the name if you’re going to treat them as a family.
GRAY: Discoveries like this cause a cascade of name changes that hinder the process of keeping the tree up to date. But Michael Donoghue, a botanist and the curator of the Peabody Museum of Natural History at Yale University, says it doesn’t have to be that way. To deal with this cascade problem, he and a group of scientists are developing something they call the PhyloCode.
DONOGHUE: In my view the idea is to not to have to assign a rank for anything.
GRAY: For anything, nothing? No ranks?
DONOGHUE: Right. Just get rid of those things. They’re not necessary.
GRAY: If Donoghue could have his way, people would no longer talk about species and larger groups of organisms by referring to them as an Order or a Family or any of that.
DONOGHUE: So the cat Family so to speak is really not equivalent to the sunflower Family in any normal way. And so, we start to communicate as though it means something, but it really doesn’t mean anything at all. There’s not the same number of species, they’re not the same age, they don’t have the same ecological breadth, so there’s no particular way in which something we call a Family is equivalent to another Family.
GRAY: And so in the case of the termites…
DONOGHUE: Under the PhyloCode way of thinking about it, you keep the name Isoptera for the termites. You know, termite is a termite, Isoptera, you know they’re the same. We haven’t changed our knowledge of that. The only thing that’s changed is our knowledge of how they’re related to cockroaches and other relatives and things like that.
GRAY: Donoghue would simply name the new part of the tree where termites branch off from their wood-boring cockroach brethren. In other words, the PhyloCode would allow us to create more branches to keep up with our discoveries of new relationships. But scientists like Eggleton from the Natural History Museum of London think the PhyloCode would require too much of an overhaul.
EGGLETON: Especially working in the kind of institution that I work in, which has an enormous amount of information classified and databased using that system, to suddenly change the system would be a disaster for us.
GRAY: Getting rid of ranks would change how textbooks are written, articles are published and how laws about species get drafted. Other opponents, like taxonomist Kurt Pickett from the University of Vermont, argue that even if the PhyloCode was a good idea, its timing is not.
PICKETT: We are in the midst of a biodiversity crisis in this world and just now is not the time to institute some new scheme that is going to hurl us into taxonomic and nomenclatural confusion.
GRAY: Despite dire predictions, Donoghue and others are forging ahead. They’ll publish their code next year.
DONOGHUE: I feel like there’s never a good time for this kind of stuff in a way. So, you know to me, it’s like why should it be set in stone, why shouldn’t this be something that changes, just like everything else in science. It seems like it’s been lucky that it’s lasted 300 years. That’s longer than most things last in science.
GRAY: Science applied to it’s own tradition, or needless chaos? For Living on Earth, I’m Ian Gray.
[MUSIC: Randy Newman “Circus Bugs” from ‘A Bug’s Life’ (Walt Disney Records/Pixar -1998)]
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