There was nothing more to be known about the matter. In most cases a palpable analogy has been substituted, in others the affinity is very obscure or altogether doubtful.
The only intelligible answer is, that their supply of food is more precarious. This is strikingly proved by the case of particular species; for we find that their abundance in individuals bears no relation whatever to their fertility in producing offspring.
In both cases there may be many individual exceptions; but on the average the rule will invariably be found to hold good. The great increase of our knowledge within the last twenty years, both of the present and past history of the organic world, has accumulated a body of facts which should afford a sufficient foundation for a comprehensive law embracing and explaining them all, and giving a direction to new researches.
Reprinted with a few corrections and some important additions, among which I may especially mention 3Ir. My own more limited powers have, it is true, enabled me now and then to seize on some conspicuous group of unappropriated facts, and to search out some generalization which might bring them under the reign of known law; but they are not suited to that more scientific and more laborious process of elaborate induction, which in Mr.
HIitherto no attempt has been made to explain these singular phmnomena, or to show how they have arisen. In the wild animal, on the contrary, all its faculties and powers being brought into full action for the necessities of existence, any increase becomes immediately available, is strengthened by exercise, and must even slightly modify the food, the habits, and the whole economy of the race.
I had intended to have considerably extended this essay, but on attempting it I found that I should probably weaken the effect without adding much to the argument. If we now consider the geographical distribution of animals and plants upon the earth, we shall find all the facts beautifully in accordance with.
But it is the same throughout Nature; every class and order of animals will contribute similar facts. It is evidently possible that two or three distinct species may have had a common antitype, and that each of these may again have become the antitypes from wlich other closely allied species were created.
We will briefly endeavour to show its bearing upon each of these. PAGE 53 Additional illustration of protective colouring in the case of the wood-dove and the robin.
Darwin had been at work long before me, and that it was not left for me to attempt to write "The Origin of Species. Daines Barrington, and others, on the song of birds.
THERE is no more convincing proof of the truth of a comprehensive theory, than its power of absorbing and finding a place for new facts, and its capability of interpreting phaenomena which had been previously looked upon as unaccountable anomalies.
The bird is capable of a very rapid and long-continued flight, so that it can pass without fatigue over the whole of the district it inhabits, and as soon as the supply of food begins to fail in one place is able to discover a fresh feeding-ground.
If each species has been created independently, and without any necessary relations with pre-existing species, what do these rudiments, these apparent imperfections mean? That during an immense, but unknown period, the surface of the earth has undergone successive changes; land has sunk beneath the ocean, while fresh land has risen up from it; mountain chains have been elevated; islands have been formed into continents, and continents submerged till they have become islands; and these changes have taken place, not once merely, but perhaps hundreds, perhaps thousands of times: We have also here an acting cause to account for that balance so often observed in nature,-a deficiency in one set of organs always being compensated by an increased development of some others-powerful wings accompanying weak feet, or great velocity making up for the absence of defensive weapons; for it has been shown that all varieties in which an unbalanced deficiency occurred could not long continue their existence.
These have all served to convince him of the correctness of his hypothesis. THE flattering reception of my Essays by the public and the press having led to a second edition being called for within a year of its first publication, I have taken the opportunity to make a few necessary corrections.
We believe we have now shown. We have, however, never been able to find a case in which the circle has been closed by a direct and close affinity.
On the average all above one become food for hawks and kites, wild cats or weasels, or perish of cold and hunger as winter comes on. If turned wild on the pampas, such animals would probably soon become extinct, or under favourable circumstances might each gradually lose those extreme qualities which would never be called into action, and in a few generations revert to a common type, which must be that in which the various powers and faculties are so proportioned to each other as to be best adapted to procure food and secure safety, —that in which by the full exercise of every part of its organisation the animal can alone continue to live.
For example, during the Silurian period all the earth was Silurian, and animals were living and dying, and depositing their remains more or less over the whole area of the globe, and they were probably the species at least nearly as varied in different latitudes and longitudes as at present.
It appears evident, therefore, that so long as a country remains physically unchanged, the numbers of its animal population cannot materially increase. The shallow sea between the Peninsula of Malacca, Java, Sumatra and Borneo was probably a continent or large island at an early epoch, and may have become submerged as the volcanic ranges of Java and Sumatra were elevated.
Many of these facts are quite different from what would have been anticipated, and have hitherto been considered as highly curious, but quite inexplicable.
With such a favourable introduction, and with such talented exponents, it must have become established if it had had any germ of truth in it; yet it quite died out in a few short years, its very existence is now a matter of history; and so rapid was its fall that its talented creator, Swainson, perhaps lived to be the last man who believed in it.Wallace, Alfred Russel, Title: Contributions to the theory of natural selection.
A series of essays By Alfred Russel Wallace Publication info: Ann Arbor, Michigan: University of Michigan Library Rights/Permissions: Where. Contributions to the Theory of Natural Selection: A Series of Essays - Ebook written by Alfred Russel Wallace.
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Contributions to the theory of natural selection. A series of essays By Alfred Russel Wallace. It was an essay which Wallace sent in to Darwin (to whom he had dedicated his most famous book, The Malay Archipelago) which impelled Darwin to publish an article on his own long-pondered theory simultaneously with that of Wallace.
[front cover] contributions to. the theory of. natural selection. a series of essays.
by. alfred russel wallace, author of "the malay archipelago," etc., etc. Dec 21, · Alfred Russel Wallace, OM, FRS (8 January – 7 November ) was a British naturalist, explorer, geographer, anthropologist and biologist. He is best known for independently proposing a theory of natural selection which prompted Charles Darwin to publish his own theory.4/5(1).Download