Lamarck to Darwin : contributions to evolutionary biology, 1809-1859 / [edited by Henry Lewis McKinney].

Date:
1971
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Lamarck to Darwin : contributions to evolutionary biology, 1809-1859 / [edited by Henry Lewis McKinney]. Source: Wellcome Collection.

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    16 Lamarck (1809) These are the two fundamental truths which can be ignored only by those who have never observed or followed the operations of nature, or by those who have allowed themselves to be carried away by the mistaken notion with which I now propose to deal....* 0 [Page 265] .... We need not adduce further examples and may now proceed to the [main] point of the discussion. The fact is that the diverse animals — each according to their own genus and species — have special habits, and an organization which is always perfectly in harmony with those habits. From the consideration of this fact, it might appear that we are free to admit either one or the other of the two following conclusions, — and that neither of them can be proven. Conclusion accepted until now: Nature (or the Author of Nature), in creating animals, has foreseen all the possible kinds of circumstances [and conditions] in which they would have to live, and has given to each species a stable organization, as well as a form which is fixed and invariable in its parts. These force each species to live in the places and climates where we find them, and to preserve the habits which are characteristic of it. My personal conclusion: Nature, in successively producing all species of animals, beginning with the most imperfect or the simplest, and ending her work with the most perfect, has caused their organization gradually to become more complex. These animals are generally distributed throughout all the habitable regions of the earth, each species coming under the influence of the environmental con¬ ditions in which it finds itself, acquiring the habits by which we know them and the modifications in their parts which observation reveals to us. The first of these two conclusions is that which has been held up to the present, that is to say, it is accepted by almost everyone. It assumes in each animal an unchanging organization and parts which have never varied, and which never will vary. It furthermore assumes that the * Omitted here are pages 236 through 264
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