Snappy Poker

Certainly Mr. Darwin’s greatest work was the book On the Origin of Species by means of Natural Selection and the Preservation of Favored Races in the Struggle for Life. In order to appreciate fully the aim and object of this work, and the change it effected in natural history, it is necessary to form a clear conception of the meaning of the term “species.” To understand, in other words, the general belief regarding the word species when Mr. Darwin’s book first appeared, and to understand what he meant, and what was generally meant, by discovering their “origin.” It is for lack of this preliminary knowledge that the majority of educated people who are not naturalists are so ready to accept the various objections and criticisms of the theory of evolution. These criticisms are still predominant in the evolution creationism controversy debate.

The term “species” was defined in this way by the botanist De Candolle: “A species is a collection of all the individuals which resemble each other more than they resemble anything else, which can by mutual fecundation produce fertile individuals, and which reproduce themselves by generation, in such a manner that we may from analogy suppose them all to have sprung from one single individual.”

The zoologist Swainson gives a somewhat similar definition: “A species, in the usual acceptation of the term, is an animal which, in a state of nature, is distinguished by certain peculiarities of form, size, color, or other circumstances, from another animal. It propagates, ‘after its kind,’ individuals perfectly resembling the parent; its peculiarities, therefore, are permanent.”

To illustrate these definitions we will take two common English birds, the rook and the crow. These are distinct species, because, in the first place, they always differ from each other in certain slight peculiarities of structure, form, and habits, and, in the second place, because rooks always produce rooks, and crows produce crows, and they do not interbreed. It was therefore concluded that all the rooks in the world had descended from a single pair of rooks, and the crows in like manner from a single pair of crows, while it was considered impossible that crows could have descended from rooks. The “origin” of the first pair of each kind was a mystery. Similar remarks may be applied to our two common plants, the sweet violet and the dog violet . These also produce their like and never produce each other or intermingle, and they were therefore each supposed to have sprung from a single individual whose “origin” was unknown.