Dandelion flight is unique, “impossible”

_{Denyse O'Leary

October 19, 2018

Evolution, Intelligent Design, Plants}

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dandelion ready to disperse the seeds/Greg Hume (CC BY-SA 3.0)

They don’t usually write this way at Nature:

Dandelion seeds fly using a method that researchers thought couldn’t work in the real world, according to a study1 published on 17 October in Nature.

When some animals, aeroplanes or seeds fly, rings of circulating air called vortices form in contact with their wings or wing-like surfaces. These vortices can help to maintain the forces that lift the animal, machine or seed into the air.

Researchers thought that an unattached vortex would be too unstable to persist in nature. Yet the light, puffy seeds of dandelions use vortices that materialize just above their surfaces and lift the seed into the air.Jeremy Rehm, “Dandelion seeds fly using ‘impossible’ method never before seen in nature” at Nature

It’s risky making rules for life forms about what is possible. Human intelligence should be impossible too.

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See also: Bats fly uniquely (2007)

and

Design Principles in the flight autostabilizer of fruit flies (2010)

Comments

Mimus:
That one lineage evolves in a particular way doesn’t mean any other has to or will.
The problem is this: if the 'door' opens, then why can only 'one' come in? If there is a "fitness" advantage for the dandelion seed, then why wouldn't it also exist for every other kind of flowering plant? Either there's a mechanism which "shuts" the door afterwards--completely unidentified until now; or, there's someone who makes that call---which, of course, means we're dealing with intelligence. Remember, Darwin's theory, and all evolutionary theories, insist that the 'species' barrier can be transversed. This is the whole basis of disagreement: "How" does this happen? Darwin speculates. The fossil record says this doesn't happen. Which do we believe?PaV_{October 24, 2018
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No, the question isn't the one you pose; it's the one I posed. Let me pose it to you again: "Why don’t those species that have something similar to the dandelion continue to add bristles until their seeds are able to fly if there is a notable ‘fitness’ advantage [to flying]? Maybe you can answer it. If you can't answer, then just say you don't have an answer. BTW, there's a presentation on all of this at Evolution News. Org.PaV_{October 24, 2018
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You continue to be wrong about fruits in Asteraceae. The "question" is just the old YEC classic "if we evolved from monkeys why are there still monkeys?" argument. That remains an ignorant question, I'm afraid. That one lineage evolves in a particular way doesn't mean any other has to or will.Mimus_{October 23, 2018
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Besides the dandelion, there is just one other species that has seeds that fly. Others have pappus, but don't fly. Subtract 20 bristles from the dandelion, and it won't fly. That's the whole point of the opening post. So, again, why don't those species that have something similar to the dandelion continue to add bristles until their seeds are able to fly if there is a notable 'fitness' advantage? Try answering the question.PaV_{October 23, 2018
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Again, knowing the first thing add the about a topic before posting on it might prevent you from making such a cool of yourself. The fruits of other Asteraceae fly just fine.Mimus_{October 23, 2018
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I did google it, Mimus. They have something similar. So, if there is a fitness advantage, why did they stop going in the direction of more bristles? Isn't 'some' bristles a waste of time if they never make it into the air?PaV_{October 23, 2018
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You probably should have googled this one... A lot of Asteraceae have this sort of fruit, which disperse individually.Mimus_{October 22, 2018
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Correction: I was considering 'extant' species; but species other than dandelions. If there is a 'fitness' advantage by havin bristles, then why aren't there seeds of other plants who have, say, 30 bristles, but which cannot now 'fly'?PaV_{October 22, 2018
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Minus:
Yes, just as birds had to carry around one useless wing for millions of years before the second one evolved!
Darwin insists that "natura non facit saltum." So, please explain how 95 bristles came about 'immediately.' Thank you.
I think you can work this one out for yourself, how many descendants should the less fit individuals leave…?
I was not considering extant species. Try answering this one:
And why haven’t other plants used this strategy?
PaV_{October 22, 2018
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According to Darwin, the plant should arrive at 95 bristles, one bristle at a time.
Yes, just as birds had to carry around one useless wing for millions of years before the second one evolved!
So, where are the intermediates? Where are they today if such a “fitness” advantage still holds today?
I think you can work this one out for yourself, how many descendants should the less fit individuals leave...?Mimus_{October 21, 2018
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ronvanwegen:
The “flying” helps them disperse further – it doesn’t prevent them propagating. It’ll just get pretty crowded around the parent so there’ll be competition for nutrients etc. Flying is more like kids owning a car so that they can live in another town rather than in their parent’s basement!
I don't think you're saying anything I wasn't saying. It's all about "fitness." If the seeds don't "propagate," then the ones who remain close to the original plant must compete with others. Thus, if the seeds fly away, then they can land in areas where they, too, can germinate, thus producing additional offspring---more so than a plant that has seeds that don't propagate. So, there is a "fitness" value in propagating. I am acknowledging this. But the question is: the seed has to get up to around 90 bristles. How does it do this? 30 bristles won't do. IOW, does the plant one day wake up and say: "Today I'm going to produce seeds with 95 bristles."? According to Darwin, the plant should arrive at 95 bristles, one bristle at a time. So, where are the intermediates? Where are they today if such a "fitness" advantage still holds today? And why haven't other plants used this strategy? The list of questions goes on. And Darwinism is completely incapable of giving us an answer other than: "Those that are 'fit' will survive. And those that 'survive' are fit." Tautologies.PaV_{October 21, 2018
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Previous studies have found that dandelion seeds always have between 90 and 110 bristles, says Nakayama. It’s “scary consistent”, and that consistency turns out to be very important.
"Scary"
It’s great to see an analysis of something we see every day but didn’t fully understand, says Richard Bomphrey, a comparative biomechanist at the Royal Veterinary College in Hatfield, UK. “To discover that there were aerodynamic mechanisms that we didn’t already know — despite the fact that we can fly things at Mach 9 — is always exciting.”
We didn't know that this precise physical construct would enable flight.Silver Asiatic_{October 20, 2018
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Evolution came up with an impossible solution to a non-problem. Seeds didn't need to fly, they could just fall like other plants. But through trial and error, lots of lucky mutations, and millions of seed-forms that didn't quite fly but were gradually moving to that (unnecessary) goal ... evolution achieved the impossible. As it always does. Good job, evolution!Silver Asiatic_{October 20, 2018
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PaV: "So, if you get down to 80, or above 130, the pollen seeds won’t fly, and hence won’t propagate..." The "flying" helps them disperse further - it doesn't prevent them propagating. It'll just get pretty crowded around the parent so there'll be competition for nutrients etc. Flying is more like kids owning a car so that they can live in another town rather than in their parent's basement!ronvanwegen_{October 19, 2018
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From Nature:
When the team designed small silicon discs to imitate these spokes, they produced models with a range of openings: from solid discs to ones that were 92% air, like the structures on the dandelion seeds. When the researchers tested these model seeds in their wind tunnel, they found that only the discs that best approximated dandelion seeds could maintain the detached vortex. If the number of openings in the discs was even 10% off of those in dandelion seeds, the vortex destabilized. The seed looks inefficient for flight because it has so much open space, says Nakayama, but these openings are what allow the unattached vortex ring to remain stable.
There are consistently 92-110 of these bristles. So, if you get down to 80, or above 130, the pollen seeds won't fly, and hence won't propagate, and hence have 'fewer' offspring, which means the 'fitness' is lower. Well, where are the intermediates. Did some weed develop 10, or 20? Do we see any kind of intermediate number of bristles? If not, then is the dandelion seed irreducibly complex?PaV_{October 19, 2018
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