I have to criticize the video below. It’s a beautiful piece of work, and the animal it shows is spectacularly well-adapted, but it does not demonstrate the fulfillment of a uniquely Darwinian prediction.
An orchid was found with a nectary that was only accessible by way of a long, narrow tube, and Darwin predicted the existence of an insect pollinator with an almost equivalently long tongue. However, an Owen or a Cuvier, scientists of that century who did not accept evolution, could have easily made the very same prediction, on the basis of created functionality: a god would not have made the flower that way unless he also, in his infallible foresight, also made a complementary pollinator. One could also make an argument based on an orchidized version of the anthropic principle: the flower is there, therefore it must have been produced by a parent flower that had been pollinated, therefore there must exist a long-tongued pollinator.
The special Darwinian character comes from the explanation of how such a phenomenon came to be; not by the fiat of some arbitrary creator, but by a set of processes that must still operate. It is to the advantage of the flower that the pollinator has to struggle a bit to reach the nectar reward, pressing itself against the flower and covering itself with pollen, while the pollinator would prefer to be able to reach in easily and without mess and fuss to get its dinner. This means that there is selection for flowers that have slightly longer nectary tubes than the insect tongues, while there is selection for insects that are able to reach all the pools of sweet nectar — but this is a race in which the insects will always be slightly behind.
What Darwin predicted was not a perfect match between nectary and proboscis, but that the insect proboscis would be slightly shorter than the nectary, and that’s what you find in his work On the Various Contrivances by which British and Foreign Orchids are Fertilised by Insects, and the Good Effects of Intercrossing. Another prediction that I haven’t found that he made explicitly is that there should be a range of heritable variation in nectary length — it could just be that that was so obvious in the collections he examined that it wasn’t necessary to state it.
Anyway, lovely as it is, a video of an insect with a remarkably long proboscis is not confirmation of Darwin’s theory. The key element of that theory is a description of a process which generates diversity over time in populations, which isn’t assessed by examining a single organism at a single moment in time.
(via Atheist Media Blog)
The question is then why the creator should make such an orchid in the first place
efficiency dictates that if you’re going to create flowers, they should be pollinated by as wide a range of pollinators as possible, rather than relying on one specialist.
In fact, we’re lucky we saw this; this system is probably unstable, if one or the other becomes endangered, they could both be wiped out very easily
What is the advantage of having such a long nectary?
I smell a quote mine
There we are, back to, “individuals don’t evolve, species evolve”.
PZ Myers: defeating creationist arguments before they even start. Brilliant!
I’ve always loved the way evolution sometimes leads to pairs like this insect and flower. So much more interesting than the “they were created that way” non-explanation. I guess that’s why I have a hard time understanding why some people don’t find evolution beautiful, compelling and inspiring.
Let me just chime in for a moment to point out that Angraecum sesquipedale, the orchid in question, is quite beautiful both as a plant and in flower. Not terribly difficult to grow and blossom, it is one of the nicer specimens in my collection. Always nice to see the unfolding of the buds and the lengthening of the nectary over the weeks of development prior to the opening of the bud. FWIW, the plant usually throws a single bloom, rarely 2. I got 3 this last year ;-)
regards,
Shirley Knott
Well that video was kinda trite without the sound, a see through Darwin? Had to be a good voice over for that not to be a bit much.
It is a bit of an odd adaption and does leave me wondering wouldn’t it be easier at this point to just chomp the end off the nectary and suck out the nectar like a kid with a waffle cone?
Re: #2
The advantage is that, because the moth is so uniquely adapted to getting the nectar from these flowers, only these moths will go for these flowers – and these moths will only go for these flowers. This means that, rather than having an insect pick up the pollen only to not come into contact with another suitable flower while still covered with pollen, the moth is guaranteed to be on the hunt for another of these orchids. So long as the moths are around, the flowers are guaranteed good pollinators – and while the flowers are around (and nothing else is able to reach the nectar), the moths are guaranteed a source of nectar.
It is simply wondrous to know that the Scientist will point out all the flaws in something that the IDiot would take full proof in. I just love it.
JC
this is a great point.
there are a range of phenomena where the evolutionary story doesn’t sound all that different from an aristotelian teleological story (‘nature designed it that way for the sake of an end’).
but there’s also a whole range of cases where the two theories make divergent predictions, and smart evolutionists focus their case on those.
to wit: the panda’s thumb.
its not the beautiful, seamless adaptations of organism-to-niche that show the superiority of evolution.
it’s the kludgey, duct-taped monstrosities; the vestigial superfluities; the improvised skins-of-teeth that are just good enough to survive. and so they do.
when aristotle said that organisms in nature act for ends, it is easy to find lots of apparent confirmatory evidence, and hard to disprove it.
but when aristotle said that nature does nothing in vain–oh, god, what a howler that was, and how the counter-evidence piles up.
Lynnai: Darwin actually discusses this happening in the wild, I think Orchids grow thicker flesh there as a protection…
can’t remember, it’s been a couple of months now since I read Origin, and I’ve never seen discussion anywhere else.
Jackal: When the insect has to really struggle to reach the nectar, it brushes against the sex organs heaps*, picking up and delivering pollen, which is why the plants always make their nectaries just a little bit longer than the insect’s proboscis… because if they’re not as long as the proboscis, the insect can get at it easily and their pollen doesn’t get spread so much
*this sounds kind of kinky. Is that why christians don’t like it?
Thanks Max. I was wondering the same thing as #2.
Did you read the post?
“It is to the advantage of the flower that the pollinator has to struggle a bit to reach the nectar reward, pressing itself against the flower and covering itself with pollen, while the pollinator would prefer to be able to reach in easily and without mess and fuss to get its dinner. This means that there is selection for flowers that have slightly longer nectary tubes than the insect tongues, while there is selection for insects that are able to reach all the pools of sweet nectar — but this is a race in which the insects will always be slightly behind.”
Re: #7
Whoops, I see there’s another question here… and another interesting one. If you chomp the end off, you get a single helping of nectar, and the flower is done for. I think it’s fair to say that any creature capable of reaching the flower and also capable of chomping the end off would either be smart enough to realise that doing so would mean it can’t come back for more later, or it’d be after something rather more substantial to begin with, so it wouldn’t bother. As Shirley (#6) says, each plant usually throws a single bloom, sometimes extending to two or three. It really wouldn’t be worth the bother of chomping the end off, unless there was a large clump of them (or perhaps if it was particularly sweet nectar – maybe it’d be an occasional tasty treat; it’s quite possible that this happens, I haven’t looked into it).
Also, if there weren’t creatures able to reach in from the top, transferring pollen as they do so, the plants wouldn’t be able to reproduce, so they wouldn’t be around anyway – there HAS to be something able to pollinate the flowers in order for there to be more than a single specimen of the plant.
Nice to see PZ being, as usual, scrupiously honest even if it helps the creos cause. I too have always been wary of using the ‘similar genetic sequences in [evolutionary]related organisms’ as evidence of evolution because the fundies can (and do) just reply ‘why wouldn’t god use the same genes to build similar structures?’ Evidence that supports both ‘points of view’ (I refuse to use the word theory for ID) doesn’t help at all. Of course, when we get down to the nitty-gritty and ask why related species have the same genetic mistakes and ERVs in the same genomic positions, things get a bit problematic for the creos.
This is way too heavy a consideration for us down here in post Roman Empire, pre Enlightenment Florida. Today’s Miami Herald announces: House passes evolution bill, with the blurb:the bill…allows teachers to expose holes in the theory of evolution. Solid journalism taking the courageous stand that there’s 2 sides to every issue. Chris
Dr. Myers, as much as your scathing commentary makes me laugh, your reserved, professionally critical commentary is even more of a pleasure for my brain. Thank you for a delightful analysis.
There are insects that bore through the nectar sack, to reach the sweet goodness within. Presumably, the orchids are able to get enough polination action that the loss to these cheaters does not cause too much of a loss.
From the OP:
Or a Lamarckist could argue that an individual insect grew a longer tongue in his effort to reach into that flower, and then passed that longer tongue on for generations. This is a nifty natural phenomenon, but you’re right…it doesn’t really demonstrate anything about the mechanism by which it occurred. Ah well.
On a side note, I hate how any mistake on the part of someone arguing for evolution ends up being seized upon by creationists/ID people as “proof” that “Darwinism” is nothing but a bunch of unsupported dogma and that ID is right….
I’m not aware that Cuvier advocated creation. He found no evidence to convince him that evolution had occurred, but that doesn’t mean he championed creation as the alternative. My understanding was that he left this as an unanswered question.
I was just musing on the fact that evolution isn’t intellegent and that the long nectary appears to be a bit of a target for borers and chompers which would indeed circumvent the polination.
Boring and chomping is more work but can be done on more then one type of flower so no, I don’t think they have to be smart at all. Presumably the flower does have some protection against this, thicker flesh, heals well, flesh that tastes bad…. but I’m still left feeling on the cusp of an idea about specialized niches bieng an arguement against ID becuase they can be so fragile. Of course not getting it all clearly and well articulated means you’re just asking to be targeted and I’m not too keen on that.
Two things. One is that “god” isn’t an explanation for anything, because of the lack of evidence for anything intelligent that makes something we call “life”. The second is that it is the whole that is explained by evolution, the concurrent evolution of plant and pollinator. Whatever the issues of having unique pollinators for plants, there is never a match between pollination and some evident intelligence (save with some of our domesticated plants), while one may very well predict matches between adaptation and pollination.
This one is the important one. In fact, I recall reading somewhere that the moth pollinating the orchid does not appear to be the one that the orchid originally evolved with. Maybe this is a faulty memory. Probably it is not, but the real point is that it doesn’t matter, there is nothing to prevent a moth that evolved a long tongue in conjunction with another plant, or set of plants, from switching over to this one, possibly even out-competing the insect with which the moth did evolve.
I think that some people think that, if Darwin predicted something, then it is an evolutionary prediction. This appears to have been more or less just a prediction, one that is not obviously tied to evolution any more than any other adaptation is. I never quite understood why it was held to be an evolutionary prediction as such.
Glen Davidson
http://tinyurl.com/2kxyc7
Should have been, “possibly even out-competing the insect with which the orchid did evolve.”
Glen Davidson
http://tinyurl.com/2kxyc7
Because it makes no sense to use genes for legs to make bat wings, instead of, say, using genes for pterodactyl wings to make bat wings. You have the most unlikely adaptations occurring if considered from a design standpoint, while it makes perfect sense from an evolutionary view that each time vertebrates evolved wings, they did so by adaptation of leg structures–those are all that are available for the evolution of wings (ok, it’s not absolutely impossible that other structures could be adapted, it’s just very unlikely).
The point of design and creation is precisely that you do not have the same constraints as evolution does. And yet the IDiots would have you believe that God “designed” life within exactly the contraints of evolution, while exhibiting none of the possibilities or contraints known in extant design processes.
But there is no evidence that supports both views, at least not in context. Analogy actually does support both design and evolutionary hypotheses (which is why it is not evidence by itself), but homology (which is typically found underneath analogies) is more or less known because it has no functional explanation. Honest creationists had to evoke “archetypes” and other ad hoc “explanations” for homology, for there is no functional or design explanation for homologies, say, between dinosaur forelimbs and bird wings.
Glen Davidson
http://tinyurl.com/2kxyc7
Another caveat: There is a kind of evolutionary-functional explanation for homologies between dinosaur forelimbs and bird wings, such as that legs function enough like wings to evolve into wings. But that’s evolutionary-functional, not design-functional, for a designer wouldn’t look at legs and think of what great wings they’d make, rather a designer would look at wings (like pterodactyl wings) and think of what great wings they’d make–the Wright brothers did that with bird wings, yet made wings virtually non-homologous with those of birds.
Glen Davidson
http://tinyurl.com/2kxyc7
Hey dudes,
I disagree with many of the points made here.
1. The video, at least, doesn’t argue that the orchid/moth proves evolution or was *predicted* by evolutionary theory. It just says that *Darwin* predicted the moth, which is true. So maybe the point is just that Darwin was a smart guy who knew a lot about orchids and was a careful observer. If it is true that he was ridiculed for the prediction (I have heard this before but haven’t heard a definitive source) then even more kudos to him.
Other people other places have made the evolutionary prediction arguments, but not this video. So criticize them, not the video.
2. It’s not at all clear that the moth is “is spectacularly well-adapted.” It’s actually pretty preposterous and inefficient and poorly designed for a moth to have a tongue 10 times its body length. Did you see the moth struggling to get it’s honking schnoz into the nectary? Ludicrous!
3. Therefore it is not at all clear that one of those pre-Darwinian biologists into the good design of nature or the functional economy of nature or whatever would have predicted that a moth must go with the flower. From their perspective flowers like that orchid could have been put there to give humans something pretty to look at, and/or recently specially created by God for obscure purposes or to show that evolution was impossible, or whatever. These were serious ideas back then.
4. I agree the evolutionary answer involves pollinator specialization, but no one here has shown that anyone before Darwin had figured out that this phenomenon exists and how it works. (And I am only saying that Darwin understood it roughly; I am not sure that Darwin had a detailed model of how pollinator specialization evolved, just that (1) orchids are highly modified monocot flowers that (2) result in elaborate machinery effecting specific pollinization, and (3) this orchid “machinery” is all a result of cooption and cobbling together flower parts with different initial functions, and thus very unlikely to be designed, which is why Darwin described his orchid book as something like “an end run around the design argument”. But this is enough for Darwin’s prediction on the orchid to be a result of his understanding of evolution as well as his general knowledge of orchids and cleverness.)
5. In summary, at present the case that this was an evolutionary prediction is at least as good as the case that it was a Darwin-was-just-smart prediction.
6. Any really serious discussion would have to (a) look up what Darwin actually wrote, (b) survey what & how people thought about orchids & their pollinators before 1859, (c) survey what people knew/thought about this orchid if anyone knew of its existence before the sample was discovered that was sent to Darwin in 1862, and (d) survey the history of the legend about Darwin’s prediction on this point. It could be a myth on the order of the “Darwin saw the finches in the Galapagos and evolution popped into his head” level, a myth which historians have debunked like many of the tales told about famous scientists (e.g. Galileo’s under-the-breath comment before the inquisition), but I suspect there is more to it than that.
7. Detail of orchid biology: in orchids the pollen isn’t loose to be transferred to many different insects, instead the pollen is found in sticky pollen packets called pollinia which ar transferred all-at-once as a unit. Each flower has only 2 pollinia which are stuck together. The pollinia contain millions of pollen grains which produce millions of tiny dust-like seeds when they fertilize another orchid. In other words, orchid flowers have the ultimate all-or-nothing strategy: a flower has to be visited by a pollinator that will (a) get the sticky pollinia attached in just the right place and (b) get them detached on another flower, also in just the right place. Each flower has to be visited only twice (once to lose pollinia and once to gain them). All the complexity of orchid flowers is aimed at achieving this specific effect.
Knowing all of this, which Darwin did but many/most/all (?) pre-Darwinians did not, and which I’m afraid some commentators here do not (!), makes Darwin’s prediction of the existence of such a ludicrous moth a lot more based on logic & theory and a lot less based on luck or arbitrary matching of parts to functions.
8. Last point: being critical of received wisdom, and especially of legendary tidbits that get passed down via word of mouth and may or may not be accurate, is highly valuable, but people are so used to saying “Hey, textbook legend X is wrong” that they often uncritically accept whatever the revisionist view is, often without subjecting it to equally thorough scrutiny. It’s a form of credulity camouflaged under the cover of the “Ha, aren’t I an enlightened critical thinker for being skeptical” feeling. This is exactly why we had a decade of chaos about the peppered moths in the media and the textbooks, when the actual science *never* supported the drastic steps of concluding that Kettlewell’s case for bird predation was fraudulent or even weak.
OK, I’m done. Comments welcome.
Right. “Examining a single organism at a single moment in time” is a creationist strategy. Comfort. Banana. Made for each other. QED.
Not that a banana is an organism per se, but you know what I mean. :-)
Woo hoo, I love the online Darwin databases:
1. Darwin’s first reaction in a letter:
2. A line in another Darwin letter, with a footnote not by Darwin:
Here’s the bit from the 2nd edition of Orchids:
Looks pretty evolutionary to me…and Darwin was smart too.
Was I the only one annoyed by the use of the word “creation” to describe this flower and moth by the narrator?
Wallace replying to the Duke of Argyll:
(A little irony there since the discovery of Neptune was a good deal of luck since many of the calculations were based on wrong assumptions.)
Any explanation is going to be evolutionary. What is not particularly evolutionary is simply predicting that a flower is serviced by a pollinator able to get to the nectary.
Glen Davidson
http://tinyurl.com/2kxyc7
I’m still left feeling on the cusp of an idea about specialized niches bieng an arguement against ID becuase they can be so fragile.
It is absolutely an argument against any ID-type or old earth creationism. The point is, how do you stop evolution? If Gaw– er, teh Deeziner carefully calibrated all these fragile and specialized coevolutionary relationships, then simple variation and adaptation will have altered them over time. The creationist is forked on two absurdities: either deny “microevolution,” or deny an old earth.
What would be cool, would be if you could find a series of fossilized orchids showing the development of the longer nectary over time.
“…an Owen or a Cuvier, scientists of that century who did not accept evolution, could have easily made the very same prediction, on the basis of created functionality…”
Yes, they could have (and today’s Owens still do), but the thing is, they didn’t. They ridiculed Darwin and held up this prediction as the ridiculous consequence of a flawed theory.
Moving on, what was that at the very end of the video: “this is certainly a good place to look for extraordinary creations“? Yipes.
Sure, but flowers almost never fossilize.
“If Gaw– er, teh Deeziner carefully calibrated all these fragile and specialized coevolutionary relationships, then simple variation and adaptation will have altered them over time.”
The fundamental assertion of the Creationists/IDers is that God is too incompetent to have invented evolution, so he has to either have created a static system (Creationism) or he has to regularly step in and personally tweak the system to keep it working (Intelligent Design). Yet they consider themselves to be the righteous ones.
Although many evolutionists are atheists, many are not: they simply accept that God may have created a system that evolves on its own without constant supervision. Unlike the Creationists/IDers, they don’t presume to put limits on God’s abilities.
I looked into orchid evolution awhile back, there are virtually no confident orchid fossils of any sort, and those that exist are body fossils, not flowers. Orchid flowers typically decay on the plant as soon as they are fertilized so it would take quite a miracle to get a fossil like you suggest.
There are however several hundred Angraecum species with nectaries of various lengths, a phylogenetic reconstruction would tell us a lot, someone may have even already done it for all I know.
Very interesting. Cool video, too. Thanks for the post, PZ.
Ah! What film! As one who enjoys growing orchids, seeing these adaptations in action can only be topped by one thing… being there. Bugs and all.
Why do people need God in order to be awed? Why can’t that be beautiful, inspiring and overwhelming just for what it is?
I ask myself that all the time, everytime I see a sunset, a whale, a spiderweb…
I’m sure Francis Collins could explain it.
I’m sure Francis Collins could explain it.
…or has convinced himself he could, anyway.
“while the pollinator would prefer to be able to reach in easily and without mess and fuss to get its dinner”
no, it wouldn’t.
(In fact, I obsess over it everytime I see a whale, caught in a spiderweb, silhouetted against a sunset…)
It’s not at all clear that the moth is “is spectacularly well-adapted.” It’s actually pretty preposterous and inefficient and poorly designed for a moth to have a tongue 10 times its body length. Did you see the moth struggling to get it’s honking schnoz into the nectary? Ludicrous!
I assume you mean this a bit tongue-in-cheek, Nick, because adaptations are viewed on a per trait basis, not as a whole.
having a 12 inch tongue on a 2 inch moth is indeed a rather spectacular adaptation.
One has to assume that the fitness increase relative to THIS particular trait overwhelms the assumed negative impacts of it’s large size.
so, yes it could indeed be said to be “spectacularly well adapted” given that perspective.
otherwise, you are tending to imply that your personal perception of the tongue as being “preposterously long” would somehow merit weight on the animal’s actual fitness.
The video is cool…
except that they keep using the word “creation” to talk about a creature. Why not say “species”?
except that they keep using the word “creation” to talk about a creature. Why not say “species”?
…because popular Discovery-Channel style nature shows hardly relate to the issue of science, and are trying to appeal to a mass audience?
seriously, one of the things that ALWAYS bothers me about shows like this is that they never ever bother to actually check the literature on the subjects they present, so they could even present a tenth of what is actually known about the subjects. Nope, they assume the pretty pictures and flowery writing (pardon the pun) will always carry the day.
Frankly, they’re probably (sadly) correct.
I’d wager a decent sum there already has been research done on this species of moth, but you’d never know that from the what was presented in the show.
One small hat-tip I would give to Jeff Corwin, is that he actually will sometimes include the people actually doing the research in his show.
as I thought, and in a journal I really like, too:
http://tinyurl.com/6o2xoo
Deep flowers for long tongues
Trends in Ecology & Evolution
Volume 13, Issue 11, 1 November 1998, Pages 459-460
^(note that this is just a note, but you will find a good list of references attached)
…and one last thing I would add is that there really isn’t as much work done on these two species’ interactions as I would have expected.
still a lot of room for some enterprising grad students.
Yeah, but science still can’t explain how the moth flies.
Yeah, but science still can’t explain how the moth flies.
that’s some rather stinky cheese bait there, Mr. fisherman.
“Creation” is fine. Created by the Blind Watchmaker.
There is a chapter in The Beak of the Finch where the writer describes how they saw, in their data, two varieties diverging, on the cusp of speciation — that was an awesome section. How better to describe it, than to say that they saw Creation taking place?
on the cusp of speciation — that was an awesome section. How better to describe it, than to say that they saw Creation taking place?
you already said what the better way to say it is.
Nick Matzke: thanks for the reading material – fascinating.
But you are in error on one minor side point:
It’s Pluto, not Neptune, that you actually mean here. The discovery of Neptune was all the triumph of Newtonian mechanics that it’s cracked up to be. Pluto, on the other hand, was much more about luck and miscalculations and incorrect data.
Ichthyic: fine, we disagree. “Speciation”, to me, doesn’t carry the grandeur that “creation” does.
#44 Ksenyia
(In fact, I obsess over it everytime I see a whale, caught in a spiderweb, silhouetted against a sunset…)
NICE!
Huh?