what darwin thought
"The whole subject of inheritance is wonderful. When a new character arises, whatever its nature may be, it generally tends to be inherited, at least in a temporary and sometimes in a most persistent manner."
Source: Charles Darwin, The Variation of Animals and Plants under Domestication, Volume 2, Chapter XII, p. 2 (London: John Murray, 1868, first edition).
On his Pangenesis hypothesis
"But besides this means of increase [cell division] I assume that cells, before their conversion into completely passive or 'formed material,' throw off minute granules or atoms, which circulate freely throughout the system, and when supplied with proper nutriment multiply by self-division, subsequently becoming developed into cells like those from which they were derived."
Source: Charles Darwin, The Variation of Animals and Plants under Domestication, Volume 2, Chapter XXVII, p. 374 (London: John Murray, 1868, first edition).
"These granules for the sake of distinctness may be called cell-gemmules, or, as the cellular theory is not fully established, simply gemmules. They are supposed to be transmitted from the parents to the offspring, and are generally developed in the generation which immediately succeeds, but are often transmitted in a dormant state during many generations and are then developed."
Source: Charles Darwin, The Variation of Animals and Plants under Domestication, Volume 2, Chapter XXVII, p. 374 (London: John Murray, 1868, first edition).
"... gemmules are collected from all parts of the system to constitute the sexual elements[sperm and eggs], and their development in the next generation forms a new being; but they are likewise capable of transmission in a dormant state to future generations and may then be developed."
Source: Charles Darwin, The Variation of Animals and Plants under Domestication, Volume 2, Chapter XXVII (Provisional Hypothesis of Pangenesis), p. 377 (London: John Murray, 1868, first edition).
"As Whewell, the historian of the inductive sciences, remarks: 'Hypotheses may often be of service to science, when they involve a certain portion of incompleteness, and even of error.' Under this point of view I venture to advance the hypothesis of Pangenesis, which implies that the whole organisation, in the sense of every separate atom or unit, reproduces itself."
Source: Charles Darwin, The Variation of Animals and Plants under Domestication, Volume 2, Chapter XXVII, p. 357 (London: John Murray, 1868, first edition).
On his Blending hypothesis
Note: Later commentators, not Darwin or his primary critic on this subject, Fleeming Jenkin, introduced the analogy of stirring a drop of black into a bucket of white paint to illustrate the concept of blending traits.
"When two commingled breeds exist at first in exactly equal numbers, the whole will sooner or later become intimately blended, but not so soon, supposing that the two breeds are equally numerous in the country, if one is in some degree prepotent over the other; for, owing to this circumstance, the whole will have a rather larger proportion of the characters of the prepotent breed. The rate at which one of two blended breeds will absorb the other depends, of course, on many circumstances; such as prolificness, vigour of constitution, and prepotency, and especially on the extent to which the breeds are kept separate, and on the proportion in number of the individuals of each which are bred together."
Source: Charles Darwin, The Variation of Animals and Plants under Domestication, Volume 2, Chapter XV (On Crossing), page 92 (London: John Murray, 1868, first edition, first issue).
"Fleeming Jenkin has given me much trouble, but has been of more use to me than any other critic; he has convinced me of the enormous difficulty of the development of even a single organ by natural selection, & has made me, I think, put the case more clearly & simply."
Source: Letter from Charles Darwin to Joseph Dalton Hooker, 30 January 1868 (Darwin Correspondence Project, Letter no. 5834).
Source: Charles Darwin, The Variation of Animals and Plants under Domestication, Volume 2, Chapter XII, p. 2 (London: John Murray, 1868, first edition).
On his Pangenesis hypothesis
"But besides this means of increase [cell division] I assume that cells, before their conversion into completely passive or 'formed material,' throw off minute granules or atoms, which circulate freely throughout the system, and when supplied with proper nutriment multiply by self-division, subsequently becoming developed into cells like those from which they were derived."
Source: Charles Darwin, The Variation of Animals and Plants under Domestication, Volume 2, Chapter XXVII, p. 374 (London: John Murray, 1868, first edition).
"These granules for the sake of distinctness may be called cell-gemmules, or, as the cellular theory is not fully established, simply gemmules. They are supposed to be transmitted from the parents to the offspring, and are generally developed in the generation which immediately succeeds, but are often transmitted in a dormant state during many generations and are then developed."
Source: Charles Darwin, The Variation of Animals and Plants under Domestication, Volume 2, Chapter XXVII, p. 374 (London: John Murray, 1868, first edition).
"... gemmules are collected from all parts of the system to constitute the sexual elements[sperm and eggs], and their development in the next generation forms a new being; but they are likewise capable of transmission in a dormant state to future generations and may then be developed."
Source: Charles Darwin, The Variation of Animals and Plants under Domestication, Volume 2, Chapter XXVII (Provisional Hypothesis of Pangenesis), p. 377 (London: John Murray, 1868, first edition).
"As Whewell, the historian of the inductive sciences, remarks: 'Hypotheses may often be of service to science, when they involve a certain portion of incompleteness, and even of error.' Under this point of view I venture to advance the hypothesis of Pangenesis, which implies that the whole organisation, in the sense of every separate atom or unit, reproduces itself."
Source: Charles Darwin, The Variation of Animals and Plants under Domestication, Volume 2, Chapter XXVII, p. 357 (London: John Murray, 1868, first edition).
On his Blending hypothesis
Note: Later commentators, not Darwin or his primary critic on this subject, Fleeming Jenkin, introduced the analogy of stirring a drop of black into a bucket of white paint to illustrate the concept of blending traits.
"When two commingled breeds exist at first in exactly equal numbers, the whole will sooner or later become intimately blended, but not so soon, supposing that the two breeds are equally numerous in the country, if one is in some degree prepotent over the other; for, owing to this circumstance, the whole will have a rather larger proportion of the characters of the prepotent breed. The rate at which one of two blended breeds will absorb the other depends, of course, on many circumstances; such as prolificness, vigour of constitution, and prepotency, and especially on the extent to which the breeds are kept separate, and on the proportion in number of the individuals of each which are bred together."
Source: Charles Darwin, The Variation of Animals and Plants under Domestication, Volume 2, Chapter XV (On Crossing), page 92 (London: John Murray, 1868, first edition, first issue).
"Fleeming Jenkin has given me much trouble, but has been of more use to me than any other critic; he has convinced me of the enormous difficulty of the development of even a single organ by natural selection, & has made me, I think, put the case more clearly & simply."
Source: Letter from Charles Darwin to Joseph Dalton Hooker, 30 January 1868 (Darwin Correspondence Project, Letter no. 5834).
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On his Pangenesis hypothesis of transmitting acquired traits to next generations
Darwin speculated that every cell in a body transmits signals of its condition in the form of "gemmules". These, he though, accumulate in reproductive gametes inside the gonads, and are transmitted to future generations. A Comment from DarwinIsDead: To be fair, Darwin labored in darkness and died before the science of Genetics was born. His simplistic conjectures reflected the fledgling state of Biology in his day. Darwin's Pangenesis hypothesis sought to give rational support to Lamarck's theory that acquired traits pass to future generations. The scientific community rejected Pangenesis after: (A) 1871, when Francis Galton published the results of his blood transfusion experiments between rabbits. (Transfusions did not transfer character-determining gemmules between rabbits as Darwin's Pangenesis hypothesis would predict); (B) 1888, when August Weismann announced his experiment with mice- (Weiss amputated the tails of 68 white mice, and bred them and five generation of their descendants. Not one of the 901 descendent offspring lacked a tail); Darwin's idea that new and old variations of an inherited character blend with time fell out of favor among the scientific community after the 1900 rediscovery of Gregor Mendel's Laws of Inheritance. |
August Weismann
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WHAT EVOLUTIONISTS TEACH
There is a marked tendency for Evolutionists and Creationists alike to slip references to what they believe about origins into lessons on how things work. Be alert! Learn to filter observational science from "historical narratives." Watch for confirmation bias, an often unconscious habit of selectively searching, remembering, and citing information that seems to favor one side of an argument over another.