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Mystery of giraffe's long necks solved?

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  • #16
    Originally posted by Teallaura View Post

    I'd noticed that - I was wondering if I was just imagining it.

    Also, giraffe - of course Lamarck applies! :


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    • #17
      Originally posted by Teallaura View Post

      Um, that doesn't actually prove the point. Browsers rarely eat the topmost leaves if they are eating from the bottom up - even bending over, the longer neck should be an advantage.

      Might mean shorter shrubs are less competitive - or just tastier...
      How so? What advantages does one get having to bend over to get something that those on that level don't have?

      I'm always still in trouble again

      "You're by far the worst poster on TWeb" and "TWeb's biggest liar" --starlight (the guy who says Stalin was a right-winger)
      "Overall I would rate the withdrawal from Afghanistan as by far the best thing Biden's done" --Starlight
      "Of course, human life begins at fertilization that’s not the argument." --Tassman

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      • #18
        Originally posted by Teallaura View Post

        Um, that doesn't actually prove the point. Browsers rarely eat the topmost leaves
        Reset of eyes. Ah - my plants are safe from Firefox after all.
        1Cor 15:34 εκνηψατε δικαιως και μη αμαρτανετε αγνωσιαν γαρ θεου τινες εχουσιν προς εντροπην υμιν λεγω
        Come to your senses as you ought and stop sinning; for I say to your shame, there are some who know not God.
        .
        "It is not divine truth that makes the man seem more innocent in what is equally sinful, but human wrong-headedness." AUGUSTINE: re adultery

        "The synoptic gospels claim that Jesus was crucified on the 15th day of Nisan and buried on the 14th day of Nisan:" Majority Consensus

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        • #19
          Originally posted by tabibito View Post

          Reset of eyes. Ah - my plants are safe from Firefox after all.
          But Chrome has been eyeing them and drooling.

          I'm always still in trouble again

          "You're by far the worst poster on TWeb" and "TWeb's biggest liar" --starlight (the guy who says Stalin was a right-winger)
          "Overall I would rate the withdrawal from Afghanistan as by far the best thing Biden's done" --Starlight
          "Of course, human life begins at fertilization that’s not the argument." --Tassman

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          • #20
            Originally posted by rogue06 View Post
            How so? What advantages does one get having to bend over to get something that those on that level don't have?
            The ability to get it. Tippy top is often out of reach of ground browsers.

            And now that I think about it, most of the green, tender shoots are going to be on the top of most brush - I was kidding before but tastier might really be part of the answer.
            "He is no fool who gives what he cannot keep to gain that which he cannot lose." - Jim Elliot

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            • #21
              Originally posted by tabibito View Post

              Reset of eyes. Ah - my plants are safe from Firefox after all.
              "He is no fool who gives what he cannot keep to gain that which he cannot lose." - Jim Elliot

              "Forgiveness is the way of love." Gary Chapman

              My Personal Blog

              My Novella blog (Current Novella Begins on 7/25/14)

              Quill Sword

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              • #22
                Source: https://nautil.us/the-giraffe-neck-evolved-for-sexual-combat-19665/



                The Giraffe Neck Evolved for Sexual Combat

                Discovery of a previously unknown ancient giraffe species offers a new look into sexual selection and evolution.

                • BY DAVID P. BARASH
                • June 10, 2022


                If you’re a fan of Rudyard Kipling’s Just So Stories, you’ll recall “How The Elephant Got His Trunk,” “How The Leopard Got His Spots,” and the like. You probably also remember from basic biology the regnant evolutionary account of “How The Giraffe Got His Long Neck.” It lent itself to contrasting Lamarckian selection—in which early giraffes stretched their necks to reach higher leaves, thereby bequeathing their long neckedness to subsequent generations—with Darwinian natural selection, in which evolution favored those individual giraffes whose genetic background endowed them with longer necks, thus selecting for this trait. Although Lamarck remains in disfavor, research recently published in the journal Science strongly suggests that a different and far sexier variant of natural selection—appropriately termed sexual selection—has been operating.1

                Time to revise the textbooks.

                But not completely. It remains true that giraffes with longer necks get to munch on leaves that are beyond the reach of other, shorter-necked competitors. Also true is that the highest leaves tend to be more nutritious. Food matters: Without enough of it, living things—however well adapted in other ways—wouldn’t survive to project their genes into the future. Looking at giraffes (and who doesn’t like to do that?), it’s all too easy to see them as merely munching machines on stilts, although their extraordinary anatomy necessitates a number of evolutionarily expensive adjustments, such as providing sufficient blood flow to that skyscraper head, and preventing too much flow when they lower their heads to drink, leading to the question, if you’re a giraffe, do you really need to reach up quite so high, easily 6 feet above all other grazers? Are those long necks merely extended chopsticks?
                Seemingly cuddly giraffes have an evolutionary history of being rather nasty to each other.


                Some years ago, a rogue band of giraffologists stuck their own necks out and began proposing a kind of biological heresy: that giraffes got their long necks not merely to better fill their bellies, but all the better to bash each other with, my dear. Think of a medieval mace, with a hard, heavy object at the end of a chain or—in the case of giraffes—a long, flexible neck, made more impactful in proportion as that neck is elongated and capable of swinging the business end with great force. We think of our own necks, when we think of them at all, as something that connects head to shoulders and that enables us to turn and tilt that head. Necks are to be protected rather than wielded. But we’re not giraffes.

                In Science, the researchers reported that an ancestral giraffe from the early Miocene (about 17 million years ago), recently discovered in northern China, had “a thick-boned cranium with a large disklike headgear, a series of cervical vertebrae with extremely thickened centra, and the most complicated head-neck joints in mammals known to date.” It turns out that those seemingly cuddly giraffes have an evolutionary history of being rather nasty to each other, especially the males. Nor are they likely to have been unique, at least in the deep past.

                Sauropod dinosaurs such as Diplodocus and Brachiosaurus also had notoriously long necks, although their anatomy doesn’t suggest weaponization … with one notable exception. Apatosaurus had unusually robust neck architecture, with armored internal structure and trapezoidal cervical vertebrae that particularly lend themselves to vigorous downward chopping motions. Apatosaurologists debate whether their subjects’ heads were typically held high or mostly horizontal. However, the heads of Apatosaurs were, if anything, unusually small, although their necks were exceptionally thick. Could they have used their necks as weapons?

                For a century after Darwin published his second best-known book, The Descent of Man, and Selection in Relation to Sex, the sexual selection part was largely overlooked in favor of its ecological counterpart (plain old natural selection), although both operate by the same mechanism: differential reproduction among genetic variants. The problem was that sexual selection is itself divisible into two components, female choice and male-male competition, and although both are now recognized as consequential, female choice of whom to mate with was considered unlikely, because it was widely misunderstood to require a conscious aesthetic sense on the part of those animals doing the choosing.

                © Copyright Original Source

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                But will they come when you do call for them? Shakespeare’s Henry IV, Part 1, Act III:

                go with the flow the river knows . . .

                Frank

                I do not know, therefore everything is in pencil.

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