The first pterosaur fossil showing complete wings

The first fossil showing the extent of the wing membranes of a pterosaur was found back in 1873.

Ferris Jabr has posted a picture: pterosaur wings.

Ernst Haeckel and radiolarians

I’m going through old books at home, currently a stack of “Horizon,” a hard-backed quarterly from the American Heritage Publishing Company. (The contributors range from Arnold Toynbee to T.S. Eliot. I’m reluctant to send them to the Goodwill.) The Spring 1976 issue contains “The Stately Mansions of the Radiolaria,” by Stephen Jay Gould.

Here’s what he says about the much-maligned Ernst Haeckel:

Ernst Haeckel was the Thomas Huxley of Germany. A brilliant and indefatigable writer and lecturer, he became the continent’s chief publicist for evolution. His books certainly had a greater impact on the general public than those of Darwin. He is best remembered today for his intriguing, but basically incorrect theory that “ontogeny recapitulates phylogeny”—that is, that individuals repeat the stages of their evolutionary ancestry during embryonic growth….

Haeckel also introduced a multitude of terms into our biological language—”plankton” among them. in his own day, he was a force to reckon with. He railed against the established church and the privileges of aristocracy, and hoped to establish an evolutionary humanism as the basis of ethical judgment. But when he was not fighting his cosmic and romantic battles, he liked to work on the taxonomy of radiolarians, for he was overwhelmed by the beauty and variety of their shells. He wrote an illustrated an enormous monograph to describe the radiolarians collected by a famous scientific expedition, the voyage of H.M.S. Challenger in 1872–1876.

In his monograph of 1877, Haeckel could do little more than catalogue in wonder. He estimated the number of known radiolarian species at 4,314, of which he described 3,508 for the first time [my emphasis] in that single work. Haeckel’s plates are a marvel of natural illustration, though in retrospect they contain as much imagination as observation. Haeckel was so convinced of the unerring geometric regularity of radiolarian parts that he drew many perfect symmetries not quite obtained by the real beasts.

This is a man who should not be dismissed in a single sentence about embryos if there’s space for more.

P.S. I made this comment over on the Pharyngula Endless Thread and decided to preserve it here.

P.P.S. Radiolarian plates.

Part of Plate 15 in Radiolarians

What does that mean, “Only a theory?”

Dr. Richard Dawkins on “Evolution is only a theory.”

Symphony of Science: A Wave of Reason

Science’s “new wave of reason.”

Phil Plait says, “Teach a man to reason and he’ll think for a lifetime.”

Darwin and the eye

Charles Darwin’s first sentence below is often quoted by his critics. However, they dishonestly omit the rest of the discussion.

Organs of extreme perfection and complication. To suppose that the eye, with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest possible degree. Yet reason tells me, that if numerous gradations from a perfect and complex eye to one very imperfect and simple, each grade being useful to its possessor, can be shown to exist; if further, the eye does vary ever so slightly, and the variations be inherited, which is certainly the case; and if any variation or modification in the organ be ever useful to an animal under changing conditions of life, then the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, can hardly be considered real. How a nerve comes to be sensitive to light, hardly concerns us more than how life itself first originated; but I may remark that several facts make me suspect that any sensitive nerve may be rendered sensitive to light, and likewise to those coarser vibrations of the air which produce sound.

In looking for the gradations by which an organ in any species has been perfected, we ought to look exclusively to its lineal ancestors; but this is scarcely ever possible, and we are forced in each case to look to species of the same group, that is to the collateral descendants from the same original parent-form, in order to see what gradations are possible, and for the chance of some gradations having been transmitted from the earlier stages of descent, in an unaltered or little altered condition. Amongst existing Vertebrata, we find but a small amount of gradation in the structure of the eye, and from fossil species we can learn nothing on this head. In this great class we should probably have to descend far beneath the lowest known fossiliferous stratum to discover the earlier stages, by which the eye has been perfected.

In the Articulata we can commence a series with an optic nerve merely coated with pigment, and without any other mechanism; and from this low stage, numerous gradations of structure, branching off in two fundamentally different lines, can be shown to exist, until we reach a moderately high stage of perfection. In certain crustaceans, for instance, there is a double cornea, the inner one divided into facets, within each of which there is a lens shaped swelling. In other crustaceans the transparent cones which are coated by pigment, and which properly act only by excluding lateral pencils of light, are convex at their upper ends and must act by convergence; and at their lower ends there seems to be an imperfect vitreous substance. With these facts, here far too briefly and imperfectly given, which show that there is much graduated diversity in the eyes of living crustaceans, and bearing in mind how small the number of living animals is in proportion to those which have become extinct, I can see no very great difficulty (not more than in the case of many other structures) in believing that natural selection has converted the simple apparatus of an optic nerve merely coated with pigment and invested by transparent membrane, into an optical instrument as perfect as is possessed by any member of the great Articulate class.

He who will go thus far, if he find on finishing this treatise that large bodies of facts, otherwise inexplicable, can be explained by the theory of descent, ought not to hesitate to go further, and to admit that a structure even as perfect as the eye of an eagle might be formed by natural selection, although in this case he does not know any of the transitional grades. His reason ought to conquer his imagination; though I have felt the difficulty far too keenly to be surprised at any degree of hesitation in extending the principle of natural selection to such startling lengths.

It is scarcely possible to avoid comparing the eye to a telescope. We know that this instrument has been perfected by the long-continued efforts of the highest human intellects; and we naturally infer that the eye has been formed by a somewhat analogous process. But may not this inference be presumptuous? Have we any right to assume that the Creator works by intellectual powers like those of man? If we must compare the eye to an optical instrument, we ought in imagination to take a thick layer of transparent tissue, with a nerve sensitive to light beneath, and then suppose every part of this layer to be continually changing slowly in density, so as to separate into layers of different densities and thicknesses, placed at different distances from each other, and with the surfaces of each layer slowly changing in form. Further we must suppose that there is a power always intently watching each slight accidental alteration in the transparent layers; and carefully selecting each alteration which, under varied circumstances, may in any way, or in any degree, tend to produce a distincter image. We must suppose each new state of the instrument to be multiplied by the million; and each to be preserved till a better be produced, and then the old ones to be destroyed. In living bodies, variation will cause the slight alterations, generation will multiply them almost infinitely, and natural selection will pick out with unerring skill each improvement. Let this process go on for millions on millions of years; and during each year on millions of individuals of many kinds; and may we not believe that a living optical instrument might thus be formed as superior to one of glass, as the works of the Creator are to those of man?

If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down. But I can find out no such case.

Evolutionary stages in eye development

Misquoting random dead French scientists

You might have heard the creationist declaim

“Evolutionism is a fairy tale for grown-ups. This theory has helped nothing in the progress of science. It is useless.”
Prof. Louis Bounoure (Former President of the Biological Society of Strasbourg and Director of the Strasbourg Zoological Museum, later Director of Research at the French National Centre of Scientific Research), as quoted in The Advocate, Thursday 8 March 1984, p. 17. (p. 5 of The Revised Quote Book)

This quotation is false. The fact is, this is two different quotations from two different people at two different times and in two different contexts. Prof. Bounoure was not director of research at the Centre, nor even a member. Even more important, the words were written fifty to sixty years ago, referring to debates long past and science that has been surpassed for forty or fifty years.

“Evolution is a fairy tale for adults” is not from Bounoure but from Jean Rostand, a much more famous French biologist (he was a member of the Academy of Sciences of the French Academy). The precise quotation is as follows: “Transformism is a fairy tale for adults.” (Age Nouveau, [a French periodical] February 1959, p. 12). But Rostand has also written that “Transformism may be considered as accepted, and no scientist, no philosopher, no longer discusses [questions – ED.] the fact of evolution.” (L’Evolution des Especes [The Evolution of the Species], Hachette, p. 190). Jean Rostand was … an atheist.

These quotations, however mangled, were taken from people who knew that evolution takes place, but felt that the explanations of mechanism were not complete or that arguing about the mechanisms was not the most fruitful form of research.

The Origin of Species online

If you can’t find your copy of The Origin of Species, know that there’s always one online at The TalkOrigins Archive.

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