The origin of species is a concept that refers to the process by which new species of living organisms emerge and evolve over time. This process is known as evolution, and it is one of the central tenets of modern biology.
The idea of evolution can be traced back to ancient Greek philosophers, who proposed that all living things have a natural tendency to change and adapt to their environment. However, it was not until the 18th and 19th centuries that the concept of evolution began to gain widespread acceptance in the scientific community.
One of the key figures in the development of the theory of evolution was Charles Darwin. In 1859, Darwin published his groundbreaking book "On the Origin of Species," in which he outlined his theory of natural selection. According to this theory, species evolve through a process of natural selection, in which individuals with traits that are better suited to their environment are more likely to survive and reproduce. Over time, these traits become more common in a population, leading to the evolution of new species.
Darwin's theory of evolution was revolutionary at the time, and it remains one of the most important scientific theories today. It has been supported by a wealth of evidence from various fields of study, including paleontology, genetics, and comparative anatomy.
Despite the overwhelming evidence in support of evolution, there are still some who reject the idea. Some argue that the theory of evolution conflicts with their religious beliefs, while others believe that it is unsupported by the scientific evidence. However, the overwhelming majority of scientists today accept evolution as a fact, and it is widely taught in schools and universities around the world.
In conclusion, the origin of species is a fascinating and complex process that has been the subject of scientific study for centuries. While there may still be some debate about the details of how evolution occurs, the overwhelming evidence supports the idea that all living things have evolved over time through a process of natural selection.
Charles Darwin: The Origin of Species (1859)
Nevertheless I cannot doubt that this process, continued during centuries, would improve and modify any breed, in the same way as Bakewell, Collins, etc. D Dissertation, University of California, Berkeley. How many of those birds and insects in North America and Europe, which differ very slightly from each other, have been ranked by one eminent naturalist as undoubted species, and by another as varieties, or, as they are often called, as geographical races! Hence the supposed extermination of so many species having similar habits with the rock-pigeon seems to me a very rash assumption. We cannot suppose that all the breeds were suddenly produced as perfect and as useful as we now see them; indeed, in several cases, we know that this has not been their history. No one supposes that our choicest productions have been produced by a single variation from the aboriginal stock.
I will then pass on to the variability of species in a state of nature; but I shall, unfortunately, be compelled to treat this subject far too briefly, as it can be treated properly only by giving long catalogues of facts. Through this universalization, the controls on population becomes only in the extreme case grounded directly on the traditional Malthusian limitations of food and space. But so many causes tend to obscure this result, that I am surprised that my tables show even a small majority on the side of the larger genera. Darwin said that, far from being constant, the difficulty in producing hybrids of related species, and the viability and fertility of the hybrids, varied greatly, especially among plants. Retrieved 17 January 2017. But to use such an expression as trying to make a fantail, is, I have no doubt, in most cases, utterly incorrect.
While Darwin had been somewhat coy about human origins, not identifying any explicit conclusion on the matter in his book, he had dropped enough hints about human's animal ancestry for the inference to be made, Vestiges. I do not believe that variability is an inherent and necessary contingency, under all circumstances, with all organic beings, as some authors have thought. It is certain that several of our eminent breeders have, even within a single lifetime, modified to a large extent some breeds of cattle and sheep. He wanted peers and society at large to understand that belief in God and evolutionary biology were not mutually exclusive. See letter to T.
Darwin: From Origin of Species to Descent of Man (Stanford Encyclopedia of Philosophy)
Furthermore, I am convinced that natural selection has been the most important, but not the exclusive, means of modification. Groups of species follow the same general rules in their appearance and disappearance as do single species. By comparing the accounts given in old pigeon treatises of carriers and tumblers with these breeds as now existing in Britain, India, and Persia, we can, I think, clearly trace the stages through which they have insensibly passed, and come to differ so greatly from the rock-pigeon. Thus, from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows. Hence the amount of difference is one very important criterion in settling whether two forms should be ranked as species or varieties. From passages in Genesis, it is clear that the colour of domestic animals was at that early period attended to. .
. Extinction caused by Natural Selection. Who can believe that animals closely resembling the Italian greyhound, the bloodhound, the bull-dog, or Blenheim spaniel, etc. I will here only allude to what may be called correlation of growth. Many leading scientists of the 18th and 19th century accepted this view, even as they were increasingly understanding the universe from a physical, material perspective. Having alluded to the subject of reversion, I may here refer to a statement often made by naturalists—namely, that our domestic varieties, when run wild, gradually but certainly revert in character to their aboriginal stocks. In this long discussion, Darwin develops the main exposition of his central theoretical concept.
It was natural selection, not independent creation, that resulted in these adaptations, Darwin argued. Glick, and David Kohn eds. Protection from the number of individuals. I have associated with several eminent fanciers, and have been permitted to join two of the London Pigeon Clubs. But as variations manifestly useful or pleasing to man appear only occasionally, the chance of their appearance will be much increased by a large number of individuals being kept; and hence this comes to be of the highest importance to success.
Retrieved 24 November 2014. This agency worked as a secondary cause in a larger plan of a superintending creator, allowing that the process of selection could go on adapting, nicely and wonderfully, organisms, if in ever so small a degree plastic, to diverse ends. This philosophical naturalist, I may add, has also quite recently shown that the muscles in the larvae of certain insects are very far from uniform. No naturalist pretends that all the species of a genus are equally distinct from each other; they may generally be divided into sub-genera, or sections, or lesser groups. As soon as the points of value of the new sub-breed are once fully acknowledged, the principle, as I have called it, of unconscious selection will always tend,—perhaps more at one period than at another, as the breed rises or falls in fashion,—perhaps more in one district than in another, according to the state of civilisation of the inhabitants—slowly to add to the characteristic features of the breed, whatever they may be. Reversions to long-lost characters.
The summary of both chapters says:. Oxford: Oxford University Press, 1859 1996. These individual differences are highly important for us, as they afford materials for natural selection to accumulate, in the same manner as man can accumulate in any given direction individual differences in his domesticated productions. Darwin said: Secondly, is it possible that an animal having, for instance, the structure and habits of a bat, could have been formed by the modification of some animal with wholly different habits? Murray's response was favourable, and a very pleased Darwin told Lyell on 30 March that he would "send shortly a large bundle of M. When we reflect on the vast diversity of the plants and animals which have been cultivated, and which have varied during all ages under the most different climates and treatment, I think we are driven to conclude that this greater variability is simply due to our domestic productions having been raised under conditions of life not so uniform as, and somewhat different from, those to which the parent-species have been exposed under nature. But most importantly, we can attempt to harness the ability to better our species through thorough scientific analysis and good old fashioned luck. Westport, CT: Greenwood Publishing Group, 2007.
In this sense he may be said to make for himself useful breeds. As Darwin noted, "Firstly, why, if species have descended from other species by insensibly fine gradations, do we not everywhere see innumerable transitional forms? In regard to the domestic animals kept by uncivilised man, it should not be overlooked that they almost always have to struggle for their own food, at least during certain seasons. The passage from one stage of difference to another and higher stage may be, in some cases, due merely to the long-continued action of different physical conditions in two different regions; but I have not much faith in this view; and I attribute the passage of a variety, from a state in which it differs very slightly from its parent to one in which it differs more, to the action of natural selection in accumulating as will hereafter be more fully explained differences of structure in certain definite directions. To judge how much, in the case of any variation, we should attribute to the direct action of heat, moisture, light, food, etc. EMBRYOLOGY, laws of, explained by variations not supervening at an early age, and being inherited at a corresponding age. Complex relations of all animals and plants throughout nature. On their different rates of change.
The Origin of Species. What is it and why is it Important?
As Darwin outlined these main lines of objection, they included first the apparent absence of numerous slight gradations between species, both in the present and in the fossil record, of the kind that would seem to be predictable from the gradualist workings of the theory chps. Youatt gives an excellent illustration of the effects of a course of selection, which may be considered as unconsciously followed, in so far that the breeders could never have expected or even have wished to have produced the result which ensued—namely, the production of two distinct strains. I am convinced that the most experienced naturalist would be surprised at the number of the cases of variability, even in important parts of structure, which he could collect on good authority, as I have collected, during a course of years. From these several reasons, namely, the improbability of man having formerly got seven or eight supposed species of pigeons to breed freely under domestication; these supposed species being quite unknown in a wild state, and their becoming nowhere feral; these species having very abnormal characters in certain respects, as compared with all other Columbidae, though so like in most other respects to the rock-pigeon; the blue colour and various marks occasionally appearing in all the breeds, both when kept pure and when crossed; the mongrel offspring being perfectly fertile;—from these several reasons, taken together, I can feel no doubt that all our domestic breeds have descended from the Columba livia with its geographical sub-species. At issue was whether the known fossil record displays a gradual progression of forms from simple to complex, as might be argued by Lamarckian transformists, or whether it supported the claim for the persistence of major groups throughout the record as might be held by someone endorsing the tradition of Cuvier see the entry on Principles of Geology 1830—33; Desmond 1984; Bowler 1976. Many treatises in different languages have been published on pigeons, and some of them are very important, as being of considerable antiquity. And I look at varieties which are in any degree more distinct and permanent, as steps leading to more strongly marked and more permanent varieties; and at these latter, as leading to sub-species, and to species.
