Convergent evolution News

Three diverse animals independently arrived at maximal fin speed solution

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From ScienceDaily:

Moving one’s body rapidly through water is a key to existence for many species. The Persian carpet flatworm, the cuttlefish and the black ghost knifefish look nothing like each other — their last common ancestor lived 550 million years ago, before the Cambrian period — a new study uses computer simulations, a robotic fish and video footage of real fish to show that all three aquatic creatures have evolved to swim using the same mechanical motion.

These three animals are part of a very diverse group of aquatic animals — both vertebrate and invertebrate — that independently arrived at the same solution of how to use their fins to maximize speed. And, remarkably, this so-called “convergent” evolution happened at least eight times across three different phyla, or animal groups, supporting the belief that necessity played a larger role than chance in developing this trait. The findings could help scientists better understand evolution as well as help pave the way for highly agile underwater vehicles.

“Chance does play a role in these animals — they don’t all adhere exactly to the optimal number 20 — but there is a point where variability can become deadly, that swimming with the wrong mechanics means you waste energy and won’t survive,” MacIver said. “The ratio of 20 is best.”More.

 

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Examples of animals evolving similar traits despite the absence of that trait in the last common ancestor, such as the wing and camera-type lens eye in vertebrates and invertebrates, are called cases of convergent evolution. – Rahul Bale et al.

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Here’s the abstract:

Examples of animals evolving similar traits despite the absence of that trait in the last common ancestor, such as the wing and camera-type lens eye in vertebrates and invertebrates, are called cases of convergent evolution. Instances of convergent evolution of locomotory patterns that quantitatively agree with the mechanically optimal solution are very rare. Here, we show that, with respect to a very diverse group of aquatic animals, a mechanically optimal method of swimming with elongated fins has evolved independently at least eight times in both vertebrate and invertebrate swimmers across three different phyla. Specifically, if we take the length of an undulation along an animal’s fin during swimming and divide it by the mean amplitude of undulations along the fin length, the result is consistently around twenty. We call this value the optimal specific wavelength (OSW). We show that the OSW maximizes the force generated by the body, which also maximizes swimming speed. We hypothesize a mechanical basis for this optimality and suggest reasons for its repeated emergence through evolution. Open access – Rahul Bale, Izaak D. Neveln, Amneet Pal Singh Bhalla, Malcolm A. MacIver, Neelesh A. Patankar. Convergent Evolution of Mechanically Optimal Locomotion in Aquatic Invertebrates and Vertebrates. PLOS Biology, 2015; 13 (4): e1002123 DOI: 10.1371/journal.pbio.1002123

So not only did life forms have to solve a special problem of  rapid locomotion, different ones had to solve it a number of times, with few if any hints from their ancestry. What are the informational probabilities of that? Wouldn’t the odds against this be greater than against it happening just once?

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57 Replies to “Three diverse animals independently arrived at maximal fin speed solution

  1. 1
    bornagain77 says:

    Nice find News! 🙂

  2. 2
    Andre says:

    So there you have it 8 times confirmed evolution is a goal orientated process. Thank you Darwin so long and thank you for the fish.

  3. 3
    Zachriel says:

    Andre: Thank you Darwin so long

    It’s called convergence. Not sure why it would be considered a fundamental issue.

  4. 4
    bornagain77 says:

    Seems like this paper fits Dr Wells ‘template’ to a tee

    Jonathan Wells on pop science boilerplate – April 20, 2015
    Excerpt: Based on my reading of thousands of Peer-Reviewed Articles in the professional literature, I’ve distilled (the) template for writing scientific articles that deal with evolution:
    1. (Presuppose that) Darwinian evolution is a fact.
    2. We used [technique(s)] to study [feature(s)] in [name of species], and we unexpectedly found [results inconsistent with Darwinian evolution].
    3. We propose [clever speculations], which might explain why the results appear to conflict with evolutionary theory.
    4. We conclude that Darwinian evolution is a fact.

    http://www.uncommondescent.com.....ilerplate/

  5. 5
    Silver Asiatic says:

    That’s an amazing little item – thank you, News.

    The ScienceNews intro to the article has some curious phrasing …

    And, remarkably, this so-called “convergent” evolution happened at least eight times across three different phyla, or animal groups, supporting the belief that necessity played a larger role than chance in developing this trait.

    Of course, why ‘remarkably’. This is just convergence. Not a big deal. Same solution, at least 8 times independently … that’s remarkable? Nahhh – it’s called convergence. Not even a fundamental issue to be concerned about. 🙂

    But then there’s this …

    this so-called “convergent” evolution …

    So-called? And convergent with scare quotes? Is there a closet IDist on the staff there? 🙂

    We could talk more about “necessity rather than chance” — also.

    (Zachriel, you might want to go there and explain that it’s called convergence and there’s nothing remarkable about it at all.)

  6. 6
    Andre says:

    Zachriel

    When a person suffers from evolutiondidit syndrome it’s very hard to distinguish fact from fiction. It is a terrible debilitating disease

  7. 7
    Dionisio says:

    News, Andre, Silver Asiatic,

    So not only did life forms have to solve a special problem of rapid locomotion, different ones had to solve it a number of times, with few if any hints from their ancestry. What are the informational probabilities of that? Wouldn’t the odds against this be greater than against it happening just once?

    What’s the big deal? What’s all the hype about?

    All that stuff is easily explained in this book:

    http://link.springer.com/book/.....19-13990-6

    Anyone who doesn’t understand the above book might want to consider watching the lectures on development referenced in the following post. Note the highlighted comments made by the professor, who is an expert on the subject:

    http://www.uncommondescent.com.....ent-561160

    😉

  8. 8
    ppolish says:

    At the molecular machine level, 100% random unguided would lead to instant death. Only a very very very small amount of random is allowed.

    At the phenotype level, random walking with no purpose will lead to failure. There are laws against that.

  9. 9
    Zachriel says:

    Andre: When a person suffers from evolutiondidit syndrome it’s very hard to distinguish fact from fiction.

    Perhaps, but convergence has been part of the theory of evolution since Darwin, so finding convergence would hardly undermine the theory.

  10. 10
    ppolish says:

    Zachary, Chapter 4 Section “Convergence of Character” had Charles D downplaying convergence and praising divergence. How would Charles handle all the evidence of convergence that had come to light since his Victorian Era?

  11. 11
    tjguy says:

    Zachriel @ 3 & 9

    It’s called convergence. Not sure why it would be considered a fundamental issue.

    Perhaps, but convergence has been part of the theory of evolution since Darwin, so finding convergence would hardly undermine the theory.

    It’s a fundamental issue Zachary, because the idea of convergence means that evolution is unfalsifiable.

    When you have organisms that are related genetically and look alike, that is homology and is claimed as evidence for evolution. So, if you have organisms that are not related genetically yet have the same functions/genes, etc., that should then be evidence against evolution. But that is not the case. Even when the evidence does not support common descent, it is still claimed as evidence for evolution. It’s the old “heads I win, tails you lose” scenario. Can you prove it was convergence? No, but that doesn’t matter. It has to be because there is no other option in your worldview so you have to stick by that answer. In other words, no matter what you find, evolution can explain it.

    Andre was right! “When a person suffers from evolutiondidit syndrome, it’s very hard to distinguish fact from fiction.”

    No matter how you slice it, evolution does not predict convergence and especially the almost innumerable examples of it. It is ubiquitous! Are you really prepared to accept random mutation as the answer to that anomaly?

  12. 12
    Zachriel says:

    ppolish: Chapter 4 Section “Convergence of Character” had Charles D downplaying convergence and praising divergence.

    Convergence is a consequence of natural selection; however,

    Darwin: It is incredible that the descendants of two organisms, which had originally differed in a marked manner, should ever afterwards converge so closely as to lead to a near approach to identity throughout their whole organisation.

    ppolish: How would Charles handle all the evidence of convergence that had come to light since his Victorian Era?

    In stride, per his statement.

  13. 13
    Zachriel says:

    tjguy: When you have organisms that are related genetically and look alike, that is homology and is claimed as evidence for evolution.

    The relationship is determined by the overall scope of traits, including genetic traits, that is, the phylogenetic fit. Convergence is in specific structures that are under selection.

    tjguy: So, if you have organisms that are not related genetically yet have the same functions/genes, etc., that should then be evidence against evolution.

    No, they are exceptions against the background nested hierarchy pattern, having been shaped by selection.

    So we have the flatworm, cuttlefish and knifefish. Their overall fit to the nested hierarchy is not in dispute, even though the one trait is shared. The convergence has to do with mobility in a watery environment. It’s the same reason fish and dolphins have hydrodynamic skin, even though they are only distantly related.

  14. 14
    ppolish says:

    Zachary, yes, Charles would consider it incredible. Did you read his next sentence? “if this had occurred, we should meet with the same form, independently of genetic connection, recurring in widely separated geological formations; and the balance of evidence is opposed to any such an admission.”

    “If this had occurred” is now “Occurs all the time”.

  15. 15
    Zachriel says:

    ppolish: “if this had occurred, we should meet with the same form, independently of genetic connection, recurring in widely separated geological formations; and the balance of evidence is opposed to any such an admission.”

    But that’s not what we see. We don’t see organisms “converge so closely as to lead to a near approach to identity throughout their whole organisation.” Rather, only certain traits, those most associated with specific adaptations, converge, while the rest of the organism retains the features of its phylogenetic position.

  16. 16
    ppolish says:

    So the “convergence” that Charles was discussing is not the same convergence that is seen in the OP. Did Charles ever give an example of convergence? Specific critters?

  17. 17
    Zachriel says:

    ppolish: So the “convergence” that Charles was discussing is not the same convergence that is seen in the OP.

    It’s the same convergence.

    ppolish: Did Charles {Darwin} ever give an example of convergence?

    Sure. An interesting example is the electric organ.

    Darwin: if the electric organs had been inherited from some one ancient progenitor, we might have expected that all electric fishes would have been specially related to each other; but this is far from the case. Nor does geology at all lead to the belief that most fishes formerly possessed electric organs, which their modified descendants have now lost.

    Phylogenetic relationships, of course, are determined by the entire scope of traits.

    Darwin: Hence in the several fishes furnished with electric organs, these cannot be considered as homologous, but only as analogous in function.

    Analogous being Darwin’s term for convergence. Darwin goes on to point out the close resemblance in fish of muscles and the electric organ. The hypothesis has empirical implications.

    1866: Darwin hypothesized that electric organs in fish are due to convergent evolution, adapted from muscle. See Darwin, Origin of Species, 4th edition 1866.
    2014: Scientists determine electric organs in fish are due to convergent evolution, and how they adapted from muscle. See Gallant et al., Genomic basis for the convergent evolution of electric organs, Science 2014.

  18. 18
    ppolish says:

    I did reread The Origin of Species recently Zachary, but thank you for reminding me of the electric fish.

    Darwin starts off by saying “The electric organs of fishes offer another case of special difficulty; for it is impossible to conceive by what steps these wondrous organs have been produced. But this is not surprising, for we do not even know of what use they are.”

    Fast forward to the present and we have better understanding. Electric mammals even.
    It should not be surprising that Science Daily refers to “so called convergent evolution” in this day and age. Natural Selection can no longer be depended on. So called Natural Selection. Purposeful guided use of Designs is becoming more and more obvious. Exciting times.

  19. 19
    Zachriel says:

    ppolish: Fast forward to the present and we have better understanding.

    1866: Darwin hypothesized that electric organs in fish are due to convergent evolution, adapted from muscle. See Darwin, Origin of Species, 4th edition 1866.

    2014: Scientists determine electric organs in fish are due to convergent evolution, and how they adapted from muscle. See Gallant et al., Genomic basis for the convergent evolution of electric organs, Science 2014.

    Lucky guess?

  20. 20
    Mapou says:

    Nothing undermines Darwinism. Just say “dirt did it!” and, instantly, it happened. Let there be convergence and there it was. It’s called “time travel creation”. Magical poofery all around.

  21. 21
    ppolish says:

    It’s muscle, bone, or blood. Blood Letting was common in Darwin’s time, so he probably thought bone or muscle a better choice. 50:50
    chance to get it right. Those are good odds, not like 1:100000000000000000000 chance of electric convergent.

    The author of the paper in the Science Daily article in the OP says “Physics or Chance”. It’s Physics Zachary. Evolution guided by Math.

    So the debate becomes “Is Math natural or unnatural”. Natural Laws or Unnatural Laws. Whichever, EVO is guided. Chance no longer acceptable Scientifically. Unguided is silly talk. Purposeless is immature.

  22. 22
    Zachriel says:

    ppolish: It’s muscle, bone, or blood.

    Darwin and his contemporaries were very aware of many types of tissue.

    You seem to have abandoned your previous tack, which was that organisms “converge so closely as to lead to a near approach to identity throughout their whole organisation.”

    On the contrary, the relationships of organisms can still be determined from their overall traits, while structures molded by natural selection stand out against the backdrop of phylogenetic relationships.

    ppolish: not like 1:100000000000000000000 chance of electric convergent.

    Actually, Gallant et al. showed how similar regulatory pathways could be targeted by selection even though they exhibited different morphologies.

  23. 23
    Joe says:

    Yes if one rules out a common design the only other answer is convergent evolution. However even that doesn’t say unguided evolution didit.

    It would be nice if someone could actually test the claims of evolutionists.

  24. 24
    Mapou says:

    Every time a Darwinist opens his or her mouth to say anything, Sir Karl Popper spins in his grave and swears.

  25. 25
    Robert Byers says:

    Good thread on a problem in evo biology.
    The common duplication of traits of very different creatures for like needs.
    Chance mutations are unlikely the mechanism. The winners with these mutations prevailing is silly.
    In fact as better investigation goes on it will be seen likeness is very common and needs better explanation then evo bio does today.
    Evos would rather jave every creature very different for like needs and then say AHA just as we predicted.
    Yet its the opposite.
    It doesn’t work eh.

    They do invoke convergent evolution like crazy as in the placental/marsupial issue.
    Yet its unlikely. marsupials are just placentas with pouches.

  26. 26
    goodusername says:

    For all these animals’ fins, the team found that the length of one undulation during swimming divided by the mean amplitude of the sideways movement is always a ratio of around 20.

    So physics says that the ratio of 20 is best, and people are surprised that the different species tend to “converge” at around 20? That would be like being surprised at the “convergent evolution” of arctic animals tending to be white.

    If we find a species that doesn’t adhere to the ratio of 20, that would require some explanation.

  27. 27
    Mapou says:

    good:

    So physics says that the ratio of 20 is best, and people are surprised that the different species tend to “converge” at around 20? That would be like being surprised at the “convergent evolution” of arctic animals tending to be white.

    If we find a species that doesn’t adhere to the ratio of 20, that would require some explanation.

    This is idiotic. Optimization is an age-old custom among intelligent designers. It’s called engineering.

    And no, ID proponents are not surprised in the least.

  28. 28
    ppolish says:

    The design kit for fur/feather coloration IS very amazing, goodusername. Much more amazing than “dark polar bears get eaten” and only white remain. Although I don’t think white is a color artic mammals and birds even see.

    Why no green fur in Nature? Plenty of forest dwellers.

  29. 29
    Mapou says:

    Environmental change drives evolutionary change.

    This is a bold faced lie because it has never been demonstrated and can never be. Besides, there is no need for it. Environmental change simply drives adaptation. Adaptation does not need Darwinism. It needs intelligent, predictive planning, designing and engineering.

  30. 30
    ppolish says:

    That’s not green fur, AS, that’s green algae living in the fur. Sorry, there is a design rule against green fur. No amount of Evo change will give one green fur. Green skin and green feathers are workable, but not fur.

    Why no green fur? There is a physics/math/design rule that says no. Design usually drives “just so”, but this time it prohibits it. Sorry Evo, can’t go there.

  31. 31
    Joe says:

    Unguided evolution can’t account for sloths nor fur…

  32. 32
    ppolish says:

    Same green algae on polar bears. Does the “just so” sloth story apply to Polar Bears?
    http://io9.com/5959012/the-big.....dest-truth

  33. 33
    ppolish says:

    Why can’t Evolution “Go Green” when it comes to fur?
    http://en.m.wikipedia.org/wiki/Red_fox

    What is stopping evolution from such an obvious adaptation? Yep, Design. Design Null Hypothesis = Design can eliminate an obviously helpful adaptation.

  34. 34
    Zachriel says:

    ppolish: Why can’t Evolution “Go Green” when it comes to fur?

    Evolution is limited to modifications of existing structures. Otherwise, Iraqi children would have Kevlar skin.

    Mammals have two types of melanin which are used for fur color; eumelanin and pheomelanin. Mixtures of these two pigments can create camouflage suitable for most environments, especially as most mammals live on the ground, and most mammals have limited color vision.
    http://www.onekind.org/uploads/a-z/a_zLeopard.jpg

    Sloths have formed a symbiotic relationship with algae to provide them camouflage. One species, Trichophilus welckeri, is passed from mother to child, is common in all sloth populations, but found in no other environment. See Suutari et al., Molecular evidence for a diverse green algal community growing in the hair of sloths and a specific association with Trichophilus welckeri (Chlorophyta, Ulvophyceae), BMC Evolutionary Biology 2010.

    The polar bear doesn’t normally harbor significant algae. That’s more common in zoos in moist climates.

  35. 35
    Joe says:

    Zachriel:

    Evolution is limited to modifications of existing structures.

    Which is why it cannot make eukaryotes from populations of prokaryotes. There isn’t anything you can do to a prokaryote to yield a eukaryote. It is close to a total redesign.

  36. 36
    Joe says:

    Aurelio and Zachriel are the low-hanging fruit.

  37. 37
    Joe says:

    Aurelio is confused. First there isn’t any evidence for its claim that the environment drives evolution and Lenski has demonstrated that evolutionary processes are severely limited. Lenski’s experiment supports baraminology, Aurelio.

  38. 38
    ppolish says:

    “Sloths have formed a symbiotic relationship with algae to provide them camouflage”

    How convenient lol. And Polar Bears? One moist mammal’s “symbiotic relationship” is another moist mammal’s nuisance.

  39. 39
    Zachriel says:

    ppolish: And Polar Bears?

    Asked an answered. Polar bear fur doesn’t normally harbor significant algae. That’s more common in zoos in moist climates. Your video is of polar bears in a zoo in Singapore, not exactly their natural environment.

  40. 40
    ppolish says:

    I’m calling BS on the “symbiotic relationship” explanation Zachary. It’s an infestation in both Polar Bear and Sloth.

  41. 41
    ppolish says:

    Sloths are most often preyed upon when they take potty breaks on the ground. Brown ground. What is the “symbiotic relationship” Zachary? Algae covered sloths taste bad?

  42. 42
    Mapou says:

    AS:

    Louis, you dilute the force of the word “lie” by using it incorrectly and frequently. It is not enough to be wrong to be called a liar. The lie must be uttered in the full knowledge that the statement is wrong. In this particular case, I fully believe what I have written. Furthermore, Richard Lenski has demonstrated evolution in progress with his classic E. coli experiment.

    A lie is a lie whether or not you believe it. People believe in lies all the time and you are one of them. And the more stupid people are, the more lies they believe in. It’s called superstition.

    Lenski has demonstrated nothing other than the pre-designed adaptive ability of E. coli. Adapted E. coli is still E. coli, not some new species. One of the obvious fallacies of evolution is that the species that have the most prolific reproduction rate are the least evolved species. This is 100% ass-backwards.

    I, too, am willing to believe but I am Popperian through and through. Just show me. Don’t tell me. Your word is worth less than nothing to me.

  43. 43
    Mapou says:

    Evolution is the religion of old fools. LOL

  44. 44
    Zachriel says:

    ppolish: What is the “symbiotic relationship”

    We already provided genomic support. Returning to the ground has to do with mutualism with moths. Try this review article, Pauli et al., A syndrome of mutualism reinforces the lifestyle of a sloth, Proceedings B of the Royal Society 2014.

    Mapou: Lenski has demonstrated nothing other than the pre-designed adaptive ability of E. coli.

    The mutations involved were apparently random, and even then, some available adaptations weren’t found by some lineages. The results are consistent with evolutionary processes.

    Mapou: One of the obvious fallacies of evolution is that the species that have the most prolific reproduction rate are the least evolved species.

    Rapid reproduction is just one of many evolutionary strategies. Termites seem to be doing fine with a much slower reproductive rate.

    Mapou: Adapted E. coli is still E. coli, not some new species.

    Lack of aerobic citrate usage is generally considered a defining characteristic of E. coli. Lenski’s experiment evolved bacteria capable of aerobic citrate usage.

  45. 45
    Joe says:

    The mutations in Lenski’s experiment were “apparently random” because we have no idea what is really going on inside of a cell.

    Lenski’s is a good example of “built-in responses to environmental cues”.

  46. 46
    ppolish says:

    Symbiosis with algae and mutualism with moths?

    Oh, what a tangled web we weave: When first we practise to deceive! Or try to explain why evolution can’t do green fur:)

  47. 47
    Mapou says:

    How old are you, Zachriel?

  48. 48
  49. 49
    Mapou says:

    58ish = old Darwinist fool.

    LOL

  50. 50
    Zachriel says:

    ppolish: Or try to explain why evolution can’t do green fur:)

    We have provided the scientific studies concerning sloth/algae symbiosis. Reading them is up to you, though.

  51. 51
    Collin says:

    I got my degree in psychology. when I took my history of psychology class, I learned that the field of psychology went through a stage where psychologists were calling everything “instincts.” Like the mating instinct, the preservation instinct and even the death instinct.

    Psychologists finally realized that they weren’t explaining anything, they were just naming things. Then they set out to explain why these apparent instincts exist rather than just labeling them.

    That seems like what convergent evolution is. It’s just a label, not an explanation.

  52. 52
    Joe says:

    So the best nature can do is algae on a sloth for the appearance of green fur? Hermit crabs don’t need their own hard shell, they formed a symbiosis with discarded shells that fit. 😉

  53. 53
    Zachriel says:

    Aurelio Smith: They have designed the (hair of) the sloth to be their perfect environment.

    The sloth’s hair actually has special grooves which house the algae.

  54. 54
    ppolish says:

    Green Algae, Green Fish, Green Amphibians, Green Reptiles, Green Birds. But Mammals are different. We’re special. Uncommon Descent. Blonde, Brunette, Redhead Going Grey to White is cool too. Santa. Good Design. Wait, who am I kidding – great design.

  55. 55
    Querius says:

    Collin @ 56 noted

    That seems like what convergent evolution is. It’s just a label, not an explanation.

    Well said!

    The problem with a label is that one can become dismissive as in “Oh that’s just an example of common convergent evolution.”

    -Q

  56. 56
    Mapou says:

    Querius:

    The problem with a label is that one can become dismissive as in “Oh that’s just an example of common convergent evolution.”

    The entire Darwinist narrative is like that. It’s all crap on the face of it.

  57. 57
    Jim Smith says:

    “Why no green fur in Nature? Plenty of forest dwellers.”

    Because most predators don’t see color the way humans do. And many animals’ vision is optimized for low light levels which affects the ratio of rods and cones so they don’t see color well anyway.

    http://www.mexicanwolves.org/i.....ow/d,News2
    http://www.livescience.com/404.....ision.html

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