Frases de John Burdon Sanderson Haldane

John Burdon Sanderson Haldane Foto
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John Burdon Sanderson Haldane

Fecha de nacimiento: 5. Noviembre 1892
Fecha de muerte: 1. Diciembre 1964

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John Burdon Sanderson Haldane fue un genetista y biólogo evolutivo británico. Junto con Ronald Fisher y Sewall Wright, fue uno de los fundadores de la genética de poblaciones.

Su principal contribución fue una serie de artículos compilados en A Mathematical Theory of Natural and Artificial Selection y resumidos en The Causes of Evolution . En ellos Haldane estudiaba dos asuntos fundamentales para la matematización de la teoría evolutiva: la dirección y las tasas de cambio de frecuencias génicas y la interacción de la selección natural con la mutación y la migración. No obstante, Haldane admitía varias causas evolutivas, como la saltación y la ortogénesis, independientemente del protagonismo de la selección natural

El trabajo de Haldane se convirtió en una de las principales contribuciones a la teoría evolutiva sintética o síntesis moderna, que restableciera la selección natural como el mecanismo esencial del cambio evolutivo, explicándolo en términos de las consecuencias matemáticas de la genética mendeliana.

Haldane acuñó también el llamado principio de Haldane, el cual afirma que el tamaño de los seres vivos define la complejidad de sus órganos internos.

Frases John Burdon Sanderson Haldane

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„If two animals have a common ancestor, their parasites are likely to be descended from those of the ancestor.“

— J. B. S. Haldane
Context: Comparative parasitology supports the evolutionary hypothesis. If two animals have a common ancestor, their parasites are likely to be descended from those of the ancestor. This principle has been applied with considerable effect to the classification of frogs and other groups. Introduction, p. 9.

„Science is as yet in its infancy, and we can foretell little of the future save that the thing that has not been is the thing that shall be; that no beliefs, no values, no institutions are safe.“

— J. B. S. Haldane
Context: Science is as yet in its infancy, and we can foretell little of the future save that the thing that has not been is the thing that shall be; that no beliefs, no values, no institutions are safe. So far from being an isolated phenomenon the late war is only an example of the disruptive result that we may constantly expect from the progress of science. The future will be no primrose path. It will have its own problems. Some will be the secular problems of the past, giant flowers of evil blossoming at last to their own destruction. Others will be wholly new. Whether in the end man will survive his ascensions of power we cannot tell. But the problem is no new one. It is the old paradox of freedom re-enacted with mankind for actor and the earth for stage.

„If much of the investigation here summarised has only proved the obvious, the obvious is worth proving when this can be done. And if the relative importance of selection and mutation is obvious, it has certainly not always been recognised as such.“

— J. B. S. Haldane
Context: Unaided common sense may indicate an equilibrium, but rarely, if ever, tells us whether it is stable. If much of the investigation here summarised has only proved the obvious, the obvious is worth proving when this can be done. And if the relative importance of selection and mutation is obvious, it has certainly not always been recognised as such. Appendix

„Another possible mode of making rapid evolutionary jumps is by hybridisation.“

— J. B. S. Haldane
Context: Where natural selection slackens, new forms may arise which would not survive under more rigid competition, and many ultimately hardy combinations will thus have a chance of arising.... Thus the distinction between the principal mammalian orders seems to have arisen during an orgy of variation in the early Eocene which followed the doom of the great reptiles... Since that date mammalian evolution has been a slower affair, largely a progressive improvement of the types originally laid down in the Eocene. Another possible mode of making rapid evolutionary jumps is by hybridisation.... hybridisation (where the hybrids are fertile) usually causes an epidemic of variation in the second generation which may include new and valuable types which could not have arisen within a species by slower evolution. Ch. IV Natural Selection, pp. 104-106.

„If human evolution is to continue along the same lines as in the past, it will probably involve a still greater prolongation of childhood and retardation of maturity. Some of the characters distinguishing adult man will be lost. It was not an embryologist or palaeontologist who said, "Except ye . . . become as little children, ye shall not enter into the kingdom of heaven."“

— J. B. S. Haldane
Context: If human evolution is to continue along the same lines as in the past, it will probably involve a still greater prolongation of childhood and retardation of maturity. Some of the characters distinguishing adult man will be lost. It was not an embryologist or palaeontologist who said, "Except ye... become as little children, ye shall not enter into the kingdom of heaven." Ch. V What is Fitness?, p. 150.

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„Where natural selection slackens, new forms may arise which would not survive under more rigid competition“

— J. B. S. Haldane
Context: Where natural selection slackens, new forms may arise which would not survive under more rigid competition, and many ultimately hardy combinations will thus have a chance of arising.... Thus the distinction between the principal mammalian orders seems to have arisen during an orgy of variation in the early Eocene which followed the doom of the great reptiles... Since that date mammalian evolution has been a slower affair, largely a progressive improvement of the types originally laid down in the Eocene. Another possible mode of making rapid evolutionary jumps is by hybridisation.... hybridisation (where the hybrids are fertile) usually causes an epidemic of variation in the second generation which may include new and valuable types which could not have arisen within a species by slower evolution. Ch. IV Natural Selection, pp. 104-106.

„We have now to ask whether God made the tapeworm. And it is questionable whether an affirmative answer fits in either with what we know about the process of evolution or what many of us believe about the moral perfection of God.“

— J. B. S. Haldane
Context: I have given my reasons for thinking that we can probably explain evolution in terms of the capacity for variation of individual organisms, and the selection exercised on them by their environment.... The most obvious alternative to this view is to hold that evolution has throughout been guided by divine power. There are two objections to this hypothesis. Most lines of descent end in extinction, and commonly the end is reached by a number of different lines evolving in parallel. This does not suggest the work of an intelligent designer, still less of an all mighty one. But the moral objection is perhaps more serious. A very large number of originally free-living Crustacea, worms, and so on, have evolved into parasites. In doing so they have lost, to a greater or less extent, their legs, eyes, and brains, and have become in many cases the course of considerable and prolonged pain to other animals and to man. If we are going to take an ethical point of view at all (and we must do so when discussing theological questions), we are, I think, bound to place this loss of faculties coupled with increased infliction of suffering in the same class as moral breakdown in a human being, which can often be traced to genetical causes. To put the matter in a more concrete way, Blake expressed some doubt as to whether God had made the tiger. But the tiger is in many ways an admirable animal. We have now to ask whether God made the tapeworm. And it is questionable whether an affirmative answer fits in either with what we know about the process of evolution or what many of us believe about the moral perfection of God. Ch. V What is Fitness?, pp. 158-159.

„Our ancestors were mostly rather rare creatures.“

— J. B. S. Haldane
Context: Wright's theory certainly supports the view taken in this book that the evolution in large random-mating populations, which is recorded by palaeontology, is not representative of evolution in general, and perhaps gives a false impression of the events occurring in less numerous species. It is a striking fact that none of the extinct species, which, from the abundance of their fossil remains, are well known to us, appear to have been in our own ancestral line. Our ancestors were mostly rather rare creatures. " Blessed are the meek : for they shall inherit the earth." Appendix, pp. 213-214.

„An inordinate fondness for beetles.“

— J. B. S. Haldane
A possibly apocryphal reply to theologians who inquired if there was anything that could be concluded about the Creator from the study of creation; as described in "Homage to Santa Rosalia, or why are there so many kinds of animals" by G. Evelyn Hutchinson in American Naturalist (May-June 1959); This alludes to the fact that there are more types of beetles than any other form of insect, and more insects than any other kind of animal. Unsourced variants: The Creator, if He exists, has "an inordinate fondness for beetles". If one could conclude as to the nature of the Creator from a study of creation, it would appear that God has an inordinate fondness for stars and beetles. The Creator, if He exists, has a special preference for beetles, and so we might be more likely to meet them than any other type of animal on a planet that would support life. As discussed [http://quoteinvestigator.com/2010/06/23/beetles/#more-734 here], a slightly different wording can be found in Haldane's 1949 book What is Life? The Layman's View of Nature, p. 248: <blockquote>The Creator would appear as endowed with a passion for stars, on the one hand, and for beetles on the other, for the simple reason that there are nearly 300,000 species of beetle known, and perhaps more, as compared with somewhat less than 9,000 species of birds and a little over 10,000 species of mammals. Beetles are actually more numerous than the species of any other insect order. That kind of thing is characteristic of nature.</blockquote> Stephen Jay Gould also discussed the quote in the article "A Special Fondness for Beetles" in the January 1993 issue of Natural History (Issue 1, Volume 2), which was reprinted on p. 377 of his book Dinosaur in a Haystack: Reflections in Natural History. Here he mentioned that Haldane had given a speech to the British Interplanetary Society in 1951, and that a report on the speech was included in Volume 10 of the Journal of the British Interplanetary Society which says that "he concluded that the Creator, if he exists, has a special preference for beetles." Gould also says that in a letter to the August 1992 issue of The Linnean, a friend of Haldane's named Kenneth Kermack said that both he and his wife Doris remembered Haldane using the phrase "an inordinate fondness for beetles": <blockquote>I have checked my memory with Doris, who also knew Haldane well, and what he actually said was: "God has an inordinate fondness for beetles." J.B.S.H. himself had an inordinate fondness for the statement: he repeated it frequently. More often than not it had the addition: "God has an inordinate fondness for stars and beetles." . . . Haldane was making a theological point: God is most likely to take trouble over reproducing his own image, and his 400,000 attempts at the perfect beetle contrast with his slipshod creation of man. When we meet the Almighty face to face he will resemble a beetle (or a star) and not Dr. Carey [the Archbishop of Canterbury]."</blockquote> The eminent nineteenth-century German theologian Matthias Joseph Scheeben had also been struck by "the hundreds of thousands of beetle species with their numerous specimens to each species" (Handbuch der katholischen Dogmatik, Vol. 2, 1878. Cf. Scheeben, The Holy Spirit, ed. F. Fuchs, 1974, p. 144), but, unlike Haldane, he did not accord it any theological significance.

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