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Thread: Thoughts on Carnivorous Plant Evolution . . .

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    BigBella's Avatar
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    Thoughts on Carnivorous Plant Evolution . . .

    One illustration which always me struck as a kid, searching through my father's old collection of scientific books, was a Rube Goldberg-style "mouse-trap" analogy of the very complex nature of a Utricularia trap, which appeared, complete with legend, in 1942's The Carnivorous Plants by Francis E. Lloyd.



    The above illustration simply begged the question of how an intermediate -- primitive -- form of such a trap could even operate? Each component is inextricably intertwined and the complexities are not limited to Utricularia, but also include Aldrovanda and Dionaea -- to name but a few.

    Pitfall traps seem far simpler to understand during the course of evolutionary development. Heliamphora's rolled leaf, however beautiful and sculptured in appearance, is still "simply" a rolled leaf. Those who have cultivated Cephalotus over the years have no doubt experienced some of the quirky intermediate leaves the plant is in the habit of producing -- strange partial forked appendages or shallow and very non-functional pitchers.

    But consider the added complexity of rapid plant movement. It is not enough for Dionaea, for example, to simply close its leaves -- and there is still some disagreement over how that is achieved. Other plants are capable of some partial movement (Mimosa pudica, the so-called "sensitive palnt" comes to mind). In addition, Dionaea also manages to provide a chemical lure, some sensitive time-delayed triggering mechanism (to keep it from closing simply under windy conditions or rain), sieve-like teeth to eliminate overly-tiny prey and, therefore, any unnecessary energy expenditures, a method of hermetically sealing the leaves, and the later resetting of the trap. Then there is the complexity of specifically developing digestive glands and enzymes to deal with its prey. It is not enough that the insect simply rots, as is the case with some primitive pitfall traps.

    William Paley posited his famous “watchmaker” teleological argument in Natural Theology in the early nineteenth century, suggesting that the very complexity of nature and the surrounding world begged some form of “intelligent” design and purpose. Others, including David Hume, refuted that populist idea at the time, pointing out nature’s occasional foibles, real defects, and monstrous mistakes. The six-legged calf at a county fair years ago immediately comes to mind -- so too, all other manner of chromosomal anomalies.

    Political correctness has unfortunately also struck the scientific world. The concept of "higher" and "lower" animals has now been replaced with the concept of basal (lower) and derived (for the more advanced, but it still means the same damn thing). If we accept the Darwinistic model of gradualistic evolution (and I imagine most of us do) with slow change over millenia, how do we satisfyingly explain the basal rise and directional selection of an organism such as the possible progenitors of Dionaea, Utricularia, or Aldrovanda to the derived plants we have today? Even if we accept Gould and Eldredge and their notion of punctuated equilibria, where evolution is not a linear matter, but can move in "fits" and "bursts" of development, it simply doesn't satisfy that ten-year old kid with the dusty books.

    I sometimes wonder whether some of those useless, quasi-functional cultivars of Dionaea that have arisen as the product of tissue culture "excesses" in recent years, offers us a glimpse of just that . . .
    “Sì perché l'autorità dell'opinione di mille nelle scienze non val per una scintilla di ragione di un solo . . ."

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    herenorthere's Avatar
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    CPs aren't that unique. The movement thing is pretty cool, but even garden flowers can open & close or turn to follow the sun. Amazing things are possible after many billions of trials and errors.
    Bruce in CT

    Madness is something rare in individuals — but in groups, parties, peoples, ages it is the rule. Friedrich Nietzsche

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    BigBella's Avatar
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    Quote Originally Posted by herenorthere View Post
    CPs aren't that unique. The movement thing is pretty cool, but even garden flowers can open & close or turn to follow the sun. Amazing things are possible after many billions of trials and errors.
    True, but phototaxis of one form or another is one thing and a sophisticated mechanism to capture a nasty housefly and consume it is quite another. I simply find it interesting and I think we can both agree that Dionaea, for example, did not spontaneously appear in its present form -- and I simply wonder at its possible predecessors. It either functions in some like fashion or it doesn't . . .
    “Sì perché l'autorità dell'opinione di mille nelle scienze non val per una scintilla di ragione di un solo . . ."

    -- Galileo "Biff" Galilei

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    Doing it wrong until I do it right. xvart's Avatar
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    I suppose that if you think about how traps of Dionaea might have worked under primitive conditions. I might suggest a simple hinge that didn't trap as they do today, but possible hinder bugs from leaving. A slower collapse that would not completely entrap a bug, but possibly keep weaker bugs from leaving. Then, maybe this would trap a few weak bugs, killing them for lack of the necessities required for the bug to live, then decompose, dropping the nutrients in the "trap" onto the ground where the roots could then absorb those needed nutrients. Although I wasn't around, I would only assume that the bogs have been around for a while, presumably some sort of nutrient deficient similar land mass.

    These plants would then, under Darwin's theories, be able to survive more effectively and pass on these genes. Eventually, some of the plants would gain some sort of absorbing function on the inside of the primitive trap, allowing the "trap" to absorb the nutrients from the bugs instead of waiting for less nutrients to fall to the ground, increasing survivability of this particular "clone."

    I suppose that the land wouldn't necessarily have to be nutrient deficient in any case. Any boost to survival rates under any conditions would help the survival of the species. As the bogs and wetlands came around, these plants would have an advantage, depending on level of evolution, far above and beyond other unique plant life surrounding them.

    The rest, as they say, is history. Just some simple musings. I find it fascinating to think of how evolution of complex mechanisms in plant life.

    xvart.
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    Two flies one pitcher. Minus the crap eating. obregon562's Avatar
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    a great topic.

    i often sit in my GH wondering things like this for literaly hours. i always imagined a drosera-like plant. All the books say thats what the ancestor was anyway haha. Some sort of slightly hairy plant rosetted plant is where it started i think. the hairs caught small bugs, giving those plants a nutrion boost. It slowly became sticky, resembling a proboscidea. then that evolved even higher to a drosera-esque plant. that slowly evolved into something like D. burmanii, with its quick snap traps. And i think those original snapping things evolved from regualr drosera hairs, capable of movement over a few hours or days. Eventually the "quick snap" developed all over, not just in one spot, and the need for stickiness was lost. bam! a primitive VFT. that snapping-dewless-dew then lost most hairs, and the few that remained became triggers, our currect VFT is realized. I dunno, just my idea!
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    BigBella's Avatar
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    Quote Originally Posted by xvart View Post
    I suppose that if you think about how traps of Dionaea might have worked under primitive conditions. I might suggest a simple hinge that didn't trap as they do today, but possible hinder bugs from leaving. A slower collapse that would not completely entrap a bug, but possibly keep weaker bugs from leaving. Then, maybe this would trap a few weak bugs, killing them for lack of the necessities required for the bug to live, then decompose, dropping the nutrients in the "trap" onto the ground where the roots could then absorb those needed nutrients. Although I wasn't around, I would only assume that the bogs have been around for a while, presumably some sort of nutrient deficient similar land mass.

    These plants would then, under Darwin's theories, be able to survive more effectively and pass on these genes. Eventually, some of the plants would gain some sort of absorbing function on the inside of the primitive trap, allowing the "trap" to absorb the nutrients from the bugs instead of waiting for less nutrients to fall to the ground, increasing survivability of this particular "clone."

    I suppose that the land wouldn't necessarily have to be nutrient deficient in any case. Any boost to survival rates under any conditions would help the survival of the species. As the bogs and wetlands came around, these plants would have an advantage, depending on level of evolution, far above and beyond other unique plant life surrounding them.

    The rest, as they say, is history. Just some simple musings. I find it fascinating to think of how evolution of complex mechanisms in plant life.

    xvart.
    That is a fine scenario and it is something that has occured to me in one form or another -- but it is fun to speculate nonetheless. Some of those useless TC-inspired cultivars of Dionaea, such as the "Wacky Traps" comes to mind when I think of the plant's possible antecedents. All of those half-steps forward and back. "Simple musings," as you said . . .

    In a similar vein, it is fascinating to appreciate all that has developed through eons of evolutionary time. What are the odds, for example, that the camera eye would develop not once but twice (in vertebrates and higher cephalopods) -- both from vastly different embryological origins and, for the most part, unrelated to each other? Or that powered flight would develop four times in the course of earth's history (insects, pterosaurs, birds, and bats) -- also by vastly different methods -- all to arrive at a similar goal?

    Nevermind, for the moment, that I have a tray full of voracious Venus Flytraps, and I don't think that a day passes when I don't hear the frantic buzzing of freshly-captured flies as the leaves grow tighter . . . and narrower.

    Where is Vincent Price when you need him?
    “Sì perché l'autorità dell'opinione di mille nelle scienze non val per una scintilla di ragione di un solo . . ."

    -- Galileo "Biff" Galilei

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    Doing it wrong until I do it right. xvart's Avatar
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    I think there is a vast (obvious) difference between above ground trapping mechanisms and subterranean trapping mechanisms. In the case of Utricularia, it is easier to guess upon the evolutionary advances it took, since typically roots serve the function of not only anchoring the plant, but absorbing nutrients. Is it so far out of the realm to think of the ways for Utricularia traps to occur? That being said, when comparing Utricularia to other carnivorous plants, such as Nepenthes, that Utricularia trapping mechanisms are more advanced? Shouldn't it be that plants that evolved trapping mechanisms above ground should be more advanced since there is an obvious lack of nutrient sufficient soil? Wouldn't it be necessary for above ground mechanisms to be more advanced?

    I suppose it could be said that they evolved to what they needed to survive and excel. But in the case of Utricularia, the mechanism is incredibly more complicated.

    Quote Originally Posted by BigBella View Post
    In a similar vein, it is fascinating to appreciate all that has developed through eons of evolutionary time.
    I often think about this, too; it blows my mind that it's been roughly 15 billion years leading up to this very moment. Talk about power and opportunity.

    xvart.
    "The tragedy of life is not that every man loses; but that he almost wins."

    "Quis custodiet ipsos custodes?"

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