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Biotech Science

Convergent Evolution Upends Honeyeaters' Taxonomy 186

Posted by kdawson
from the whole-new-family dept.
grrlscientist writes in with a beautiful piece of science, beautifully explicated. The poignant bit is that the birds in question are all extinct. "Every once in awhile, I will read a scientific paper that astonishes and delights me so much that I can hardly wait to tell you all about it. Such is the situation with a newly published paper about the Hawai'ian Honeyeaters. In short, due to the remarkable power of convergent evolution, Hawai'ian Honeyeaters have thoroughly deceived taxonomists and ornithologists as to their true origin and identity for more than 200 years."
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Convergent Evolution Upends Honeyeaters' Taxonomy

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  • Nothing New (Score:5, Interesting)

    by elrous0 (869638) * on Tuesday December 16, 2008 @05:20PM (#26137683)

    There have been debates over the taxonomy of odd creatures (with similarities to other known creatures) forever. Sometimes simple physical resemblence just doesn't really tell the tale. Of course, evolution producing similar looking/behaving birds is nothing new either (just look at how similar African parrots [wikipedia.org] and South American parrots [parrotparrot.com] are to one another).

    The really great debates come when zoologists get into trying to classify an animal that looks like (or behaves like) two DIFFERENT known creatures. One of my personal favorites is the Red Panda [wikipedia.org]. The bottom of its body and claws look like a bear's (you can see it clearly in this picture [wikimedia.org]) and it eats only bamboo, just like a Giant Panda. But the rest of it looks like a raccoon. This cute little furball finally had to be given its own unique family [wikipedia.org], because no one was quite sure where to put the little bastard. And it's still debatable if it truly deserves its own family.

    • Re: (Score:2, Funny)

      by timewasting (1230064)
      That's why DNA has become so useful for classification. Much like this new family of birds, it had to come from someplace. If it is so genetically dissimilar to everything else, than a new family is great.

      If it's just a funny-looking giant-panda-family relative then it gets a different genus and we figure out how to save it. If it's a racoon-family relative we see how quickly we can hunt the thing into extinction.
    • by iroll (717924)

      Regarding the parrots, it was my understanding that all parrots (worldwide) are of common ancestry. Sort of like how all elephants and mammoths were of common ancestry, even though they were essentially worldwide and of many distinct varieties.

    • by RockDoctor (15477)

      This cute little furball

      Red Panda. Yes, definitely cute - I could live with the idea of one of them as a house pet, as could the wife. Unfortunately, I've also got no delusions ata ll about how destructive they'd be to the house, and a garden run is not on the agenda. Oh well, nice idea.

      finally had to be given its own unique family, because no one was quite sure where to put the little bastard. And it's still debatable if it truly deserves its own family.

      Define "family" ; what biological characteristic co

  • by mcgrew (92797) * on Tuesday December 16, 2008 @05:24PM (#26137749) Homepage Journal

    The link to the name is to a newer entry in the blog in question, which is not surprisingly hers.

    Her slashdot page is here [slashdot.org]. I see no comments, I wish she would join more discussions, her journals are interesting enough.

    Where'd all these girls come from lately, anyway? It's as if all these women were wondering where to get a man who wouldn't be too scary, and then "oh wow, I know a place where there's lots and lots of guys and they're all scared of US! Too bad they're all nerds, but you can't have everything..."

    • Re: (Score:3, Informative)

      by genner (694963)

      Too bad they're all nerds, but you can't have everything..."

      I'm a geek you insensitive clod.
      A world of difference there is.

      • by dwye (1127395)

        > I'm a geek you insensitive clod.
        > A world of difference there is.

        So, bit off any good live chicken heads, lately?

        Or do you just get by shoving sharp objects into your flesh?

        Personally, I would not proclaim myself a carnival freak, but that is everyone's personal decision.

        • by genner (694963)

          I would not proclaim myself a carnival freak, but that is everyone's personal decision.

          and a proud decision it is.

    • Hadn't you heard? All of the eHarmony rejects get automatically redirected here. The Taco is trying to help us nerds out. Fortunately, you don't have to be a sociopath to be rejected; it just means you don't fit their mold.
    • Re: (Score:3, Insightful)

      by the_humeister (922869)

      How do you know that "she" isn't really a "he"? We're posting on the internet after all, where that 23 year-old hot chick who's all over you in the chat rooms is really a 47 year-old obese man living in his mother's basement.

    • by grrlscientist (1127371) on Tuesday December 16, 2008 @05:43PM (#26138007) Homepage
      Ah, thanks for the kind invitation to join your discussions. i wish i had more time to do so, but alas, i have only a few hours per day of internet access, so i spend most of that time looking for papers to write about and answering emails as well as publishing my essays and images. but i will try to make more of an effort to comment here now and again!
    • by fermion (181285)
      Posts like this is why girls hide. The assumption that because they are a girl online, they want a man, or need a man, or are attracted to men. There is more to life than that. I know that to some, finding the hookup for the evening is all that life is about, but to some science and all that crap is interesting, and having a discussion about it without all the sex stuff, not that there is anything wrong with sex, it an interesting evening in itself. Especially when followed, intermingled, or otherwise c
      • by dwye (1127395)
        What's the matter? Can't find your spin-complementary particle, so none of us can, either?
      • by richlv (778496)

        i prefer to blame religions for demonising sexuality for so long, which in turn makes most people unable to communicate about it in a normal way :>

    • by AmberBlackCat (829689) on Tuesday December 16, 2008 @06:52PM (#26138881)

      Where'd all these girls come from lately, anyway?

      We've come to be your new estrogen-based overlords, and we're offering free iPods to the first 100 people who welcome us.*

    • by Intron (870560)

      "Where'd all these girls come from lately, anyway?"

      Just because someone doesn't advertise their gender, why would you assume they are male? Do you believe that you can tell from their comments?

  • by B5_geek (638928) on Tuesday December 16, 2008 @05:30PM (#26137853)

    I realize that in this case (being dead for 200 years) it is more difficult, but why don't they _just_ use DNA sequencing to determine the classification of animals?

    Observation (of both behaviour and appearance) is influenced by the observer and is variable. Two people never see the same thing the same way. Ask a man and wife what colour the living-room couch is and you will get two different answers! =)

    The DNA sequence will never lie, and that sequence will tell us FAR more about common evolutionary traits then our eyeballs will.

    • by radtea (464814) on Tuesday December 16, 2008 @05:39PM (#26137957)

      The answer is two-fold: money, and existing taxonomies are mostly correct.

      Biologists have limited resources, so comprehensive reassessment of the entire tree of life based on genetic analysis is going to get done bit by bit over a long time, and we know we're pretty safe going with what we've got in the meantime.

      And while enough genetic analysis has been done to confirm traditional taxonomy on quite a few species, it is only the cases where there is a disagreement that it makes the news. In all the other cases they agree, so traditional taxonomy is left intact.

      There are a few dramatic cases like this one, though. There are a couple of species of lizard in the Yucatan that have an extra cervical vertebrae that turn out to have independently evolved that way (I prefer the term "independent evolution" rather than "convergent evolution", as the latter may confuse laypeople into thinking that distinct species have somehow become one.)

      In those cases, genetic taxonomy wins, but they are always going to be in the minority.

      • by ConanG (699649)
        I agree that convergent evolution could sound confusing to lay people. Independent evolution doesn't sound much better, though. It's not quite descriptive enough. I mean, most things evolve independently, don't they?

        How about analogous evolution? It's quite descriptive, and many lay people wouldn't confuse it with anything.
    • by Daniel Dvorkin (106857) * on Tuesday December 16, 2008 @06:22PM (#26138471) Homepage Journal

      Another poster, who is probably a biologist, gave two very good answers to your question; as a bioinformatician, I'll give a third. You're right that DNA doesn't lie, but we can have a damn hard time figuring out what it's trying to tell us. There is no universally agreed-upon method for reconstructing phylogenetic trees from sequence data -- Google on "phylogenetic algorithm" to see the enormous number of methods that people have come up with, and what an active area of research this continues to be. Also, the Linnaean taxonomic system, obviously, was not designed with modern genetics in mind, and trying to shoehorn phylogenetic data into this system (which is pretty much what everybody does, even if they're not happy about it) can lead to bizarre results. Until we have what everyone agrees is really a gold standard method for reconstructing ancestral trees, this is the way it's going to be.

      • by dargaud (518470)

        There is no universally agreed-upon method for reconstructing phylogenetic trees from sequence data

        And after reading a paper about how most arthropods may actually hybrids between two or more original animals, I completely gave up on that idea. Some people think that an insect and its larvae were originally two separate animals. So on which branch of the tree do you place the hybrid ?

    • by corbettw (214229)

      Ask a man and wife what colour the living-room couch is and you will get two different answers! =)

      Yes, but in that case, at least we'll know which of them is right (unless the other wants to sleep on said couch that night).

    • one of the main problems is horizontal gene transfer. an example of this would be camels and llamas which due to a freak of nature can reproduce and their offspring may well be fertile. if these two populations of quite disparate animals did come together due to geographic changes and interbreed (which is unlikely for a number of reasons), the resulting dna would be quite confusing.

      in fact the basic idea of a 'tree of life' is quite untidy. what happens for example if a virus infects a host and splices i
  • Nice blog reporting on a nifty bit of biological research. In the last forty years we have seen a change from constructing phylogenetic trees based on phenotype to constructing them based on genotype. This has resulted in a number of nice surprises like this. Good to see Mayr's hypothesis about these birds borne out.
  • by jollyreaper (513215) on Tuesday December 16, 2008 @06:02PM (#26138209)

    I was always impressed by the similarities between sharks, dolphins, and icthyosaurs. Similarly, there's a phenomenal similarity between the flying reptiles such as the pterodactyls and bats with finger bones modified with flaps of skin to make wings. There's also the similarities between various species of gliding tree mammals, the flying squirrels and lemurs and the like. One can also talk of amazing developments with marsupials which had armored herbivores similar to a rhino and carnivores like a leopard-form. (and let's not forget that a Triceratops is built awfully similar to a rhino down to the armored hide, horns, and heavy, stocky legs.) All of these from obviously unrelated lines of descent converging on similar forms to satisfy ecological niches. If I recall correctly, there's also a type of fish that developed a false-placenta for live-birthed young -- it's not a true placenta because it isn't a placental animal but it serves the same purpose. I believe this fish was in the extended shark family.

    The other thing that really amazes me is how the theory of evolution makes certain predictions that you'll simply not see contradicted. For example, there's the general rule that animals will adapt existing limbs for various purposes so you might see a rodent develop forelimbs into wings but you will not see a rodent sprout brand new wings from its back while retaining the previous four limbs. Even the weirdest body parts you can find can be seen to be modifications, not wholly new structures sprung forth from nothing. You won't see a bird suddenly come with three eyes or an elephant with a cyclopean eye or a cat with eight legs like a spider (barring genetic defects that will be unable to reproduce).

    What's also amazing is how the lines between species get blurry. The old definition is that two populations are split as a species when they cannot interbred and create viable offspring. But we've seen from zoos that populations that don't mix in the wild can produce viable offspring such as ligers, tygons, then there's the blonde grizzlies that are a hybrid of grizzly and polar bear that did occur in the wild... All of these animals come from common ancestors if you go back far enough and it makes you wonder just how freely genes could be traded back and forth with the right technology and a proper understanding of genetics.

    • by lawpoop (604919) on Tuesday December 16, 2008 @07:28PM (#26139319) Homepage Journal
      My favorite example is the Naked Mole Rat. It lives in Africa in underground, and it is a kind of rat. However, as far as mammals go, it's very weird.

      First of all, it's completely cold blooded. It cannot regulate its temperature at all. It's also blind and hairless. They have a queen that gives birth , and the others are workers in various castes, such as tunnel-maintainers, guards, or nurses.

      So convergent evolution also happens in social structures, not just physiology.
    • Re: (Score:3, Informative)

      Just remember, the lines between species are completely arbitrary and defined by us as a matter of convenience; we like to be able to classify things into groups. Ma Nature will ignore our arbitrary classifications and do whatever the physical laws of the universe (in the case of your examples, in the form of biochemistry) allow. Personally, I think that is very cool and very humbling at the same time. :)

      Anyway, just wanted to make that point on an otherwise very interesting post. Don't get too excited abou

  • by florescent_beige (608235) on Tuesday December 16, 2008 @06:23PM (#26138489) Journal

    Maximum likelihood phylogram constructed from analysis of up to 421 nucleotide sites of b-fibrinogen introns 5 and 7 combined. At nodes are Bayesian posterior probabilities and ML bootstrap values (100 repetitions).

    There are two kind of people in the world...the kind that thinks the new Day the Earth Stood Still is science fiction, and the kind that thinks it would have been if Klaatu had said to Barnhardt something like that.

    • There are two kind of people in the world...the kind that thinks the new Day the Earth Stood Still is science fiction, and the kind that thinks it would have been if Klaatu had said to Barnhardt something like that.

      Nah ... then it would have been science, not sci-fi. And nobody goes to the IMax to see science.

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