The junk DNA quotes of interest series.

One of the things I am happiest about having back online with the restored blog is the Quotes of Interest series. I had gone through the contemporary primary literature describing the discovery of each new category of non-genic DNA and showed that in every single case, functions were considered for these sequences (if not outright assumed to exist). Here’s the list of posts from this series:

Darwin caricatures.

Darwin’s views are often misrepresented to the point of caricature, as we all know, but there have also been plenty of examples of literal caricature of Darwin in the popular media. I recently gave some talks about evolutionary imagery, which included popular press cartoons from the 1800s that had a common theme of caricaturing Darwin as a chimp or having non-human apes exhibiting human characteristics and behaviour. This seems like as good a day as any (the 150th anniversary of the Origin, and all) to post my collection for your enjoyment.


Lamarck in Nature.

In yesterday’s issue of Nature, Dan Graur and co-authors provide a “book review” of Lamarck’s 1809 treatise Philosophie Zoologique. It’s not so much a literary review per se as a brief essay on Lamarck’s unflattering and unwarranted legacy. Lamarck was the first to propose a scientific theory of evolution, and he coined the terms “invertebrate” and “biology”. Unfortunately, Lamarck’s important contributions are often clouded by misconceptions about what he actually said, both by critics and by modern authors who insist on (mis)labeling the inheritance of acquired characteristics as “Lamarckian”, especially when discussing epigenetics research. (For my comment on this, see here and here). Thankfully, Graur et al. hit on both of these issues, and make a much-needed appeal for clarification and recognition of Lamarck’s contributions.

Note the following parts, which are particularly important:

Recently, Lamarck has been invoked once more, again wrongly in our view, in the field of epigenetics — the study of phenotypic and gene-expression changes that occur without a change in the genetic material.

Recognition of Lamarck’s contribution is hindered by two persistent misconceptions. First, people wrongly assume that he believed in the direct induction of advantageous hereditary changes by the environment. Yet he writes repeatedly against this notion: “For, whatever the environment may do, it does not work any direct modification whatever in the shape and organization of animals.” The second misconception concerns volition. A popular caricature of Lamarckism depicts an animal, usually a giraffe, wishing to reach the upper branches of trees, and acquiring a long neck through will alone. This error may have originated from the mistranslation of the French ‘besoin‘ — meaning ‘need’ — into the ambiguous term ‘want’, which can mean both ‘desire’ and ‘need’. This poor choice by the 1914 translator was probably influenced by Cuvier’s use of the word “désir” in his damning eulogy.

More Lamarck:

Lamarck on Genome Research (2004).

I came across this cover of the journal Genome Research from 2004.

Genomic imprinting is an epigenetic phenomenon where expression of a gene in this generation depends on whether it resided in a male or female the previous generation, a Lamarckian-like inheritance (portrait: Jean Baptiste Lamarck). Comparative phylogenetic footprint analysis of mammalian species from the nonimprinted monotremes (purple region) and the imprinted marsupials (magenta region) and eutherian mammals (pink region) was used to identify putative cis-acting elements (sequence shown) involved in the origins and evolutionary maintenance of genomic imprinting. Members of the oviparous monotremes (echidna and platypus) and viviparous marsupials (opossum) and eutherians (mouse, lemur, and human) are pictured.

It does not bother me that people want to rescue Lamarck’s reputation — he deserves vastly more respect than he currently gets for his major contributions to taxonomy and evolutionary biology. What bothers me is the effort to present anything remotely resembling the inheritance of acquired characters as Lamarckian. This is just bad history for several reasons, given that Lamarck rejected any direct input from the environment and that the inheritance of acquired traits was not original to Lamarck. It’s disappointing to see a journal fall for this in the same way that others have.

Again with the Lamarckism…

Press release from the Quarterly Review of Biology.

100 Reasons to Change How We Think About Genetics

Article Reviews Evidence for Epigenetic Inheritance in Wide Range of Species
For years, genes have been considered the one and only way biological traits could be passed down through generations of organisms.

Not anymore.

Increasingly, biologists are finding that non-genetic variation acquired during the life of an organism can sometimes be passed on to offspring—a phenomenon known as epigenetic inheritance. An article to be published this week in The Quarterly Review of Biology lists over 100 well-documented cases of epigenetic inheritance between generations of organisms, and suggests that non-DNA inheritance happens much more often than scientists previously thought.

Biologists have suspected for years that some kind of epigenetic inheritance occurs at the cellular level. The different kinds of cells in our bodies provide an example. Skin cells and brain cells have different forms and functions, despite having exactly the same DNA. There must be mechanisms—other than DNA—that make sure skin cells stay skin cells when they divide.

Only recently, however, have researchers begun to find molecular evidence of non-DNA inheritance between organisms as well as between cells. The main question now is: How often does it happen?

“The analysis of these data shows that epigenetic inheritance is ubiquitous …,” write Eva Jablonka and Gal Raz, both of Tel-Aviv University in Israel. Their article outlines inherited epigenetic variation in bacteria, protists, fungi, plants, and animals.

These findings “represent the tip of a very large iceberg,” the authors say.

For example, Jablonka and Raz cite a study finding that when fruit flies are exposed to certain chemicals, at least 13 generations of their descendants are born with bristly outgrowths on their eyes. Another study found that exposing a pregnant rat to a chemical that alters reproductive hormones leads to generations of sick offspring. Yet another study shows higher rates of heart disease and diabetes in the children and grandchildren of people who were malnourished in adolescence.

In these cases, as well as the rest of the cases Jablonka and Raz cite, the source of the variation in subsequent generations was not DNA. Rather, the new traits were carried on through epigenetic means.

There are four known mechanisms for epigenetic inheritance. According to Jablonka and Raz, the best understood of these is “DNA methylation.” Methyls, small chemical groups within cells, latch on to certain areas along the DNA strand. The methyls serve as a kind of switch that renders genes active or inactive.

By turning genes on and off, methyls can have a profound impact on the form and function of cells and organisms, without changing the underlying DNA. If the normal pattern of methyls is altered—by a chemical agent, for example—that new pattern can be passed to future generations.

The result, as in the case of the pregnant rats, can be dramatic and stick around for generations, despite the fact that underlying DNA remains unchanged.


New evidence for epigenetic inheritance has profound implications for the study of evolution, Jablonka and Raz say.

“Incorporating epigenetic inheritance into evolutionary theory extends the scope of evolutionary thinking and leads to notions of heredity and evolution that incorporate development,” they write.

This is a vindication of sorts for 18th century naturalist Jean Baptiste Lamarck. Lamarck, whose writings on evolution predated Charles Darwin’s, believed that evolution was driven in part by the inheritance of acquired traits. His classic example was the giraffe. Giraffe ancestors, Lamarck surmised, reached with their necks to munch leaves high in trees. The reaching caused their necks to become slightly longer—a trait that was passed on to descendants. Generation after generation inherited slightly longer necks, and the result is what we see in giraffes today.

With the advent of Mendelian genetics and the later discovery of DNA, Lamarck’s ideas fell out of favor entirely. Research on epigenetics, while yet to uncover anything as dramatic as Lamarck’s giraffes, does suggest that acquired traits can be heritable, and that Lamarck was not so wrong after all.

Eva Jablonka and Gal Raz, “Transgenerational Epigenetic Inheritance: Prevalence, Mechanisms, and Implications for the Study of Heredity and Evolution,” The Quarterly Review of Biology, June 2009.

Tell me, how does short-term heritability of methylation, presumably within genetically determined boundaries, bear any resemblance to giraffes stretching their necks?

Why is the “Lamarck was kinda correct” angle so irresistible?

Anyway, I look forward to seeing the argument for how this has major evolutionary impacts, and not just relevance for phenotypic plasticity.

Abigail Lustig testimony in Texas.

I feel very strongly that scientists should know the history of their discipline, as this is of substantial importance in guiding new research and preventing the same tired arguments from continually resurfacing (case in point, the myth that “junk DNA” was dismissed as totally nonfunctional or that epigenetics represents “neo-Lamarckism”). In this sense, the lessons provided by historians and philosophers can be relevant for modern science. Familiarity with the history of science is also critical for effective teaching, so again, historians can play an influential role in improving science education. This is true not only for university-level science courses taught by professional scientists, but also in protecting education standards at the high school level.

Here is an example of that — Dr. Abigail Lustig, a historian at the University of Texas Austin, presenting her testimony before the Texas Board of Education. It is very brief, but eloquently clarifies the crucial distinction between evolution as fact and as theory, and the substantial difference in historical debate and timing of acceptance of Darwin’s ideas on these two issues.

For my take, see Evolution as fact, theory, and path in E:EO.

Lamarck didn’t say it, Darwin did.

We have heard quite a lot in recent times about a resurgence of “Lamarckian” mechanisms, based largely on findings involving epigenetics. In this case, environmental differences cause changes in the patterns of expression of genes, and these alterations can sometimes be passed on through at least a few generations.

There are two reasons why it is inaccurate to consider this kind of change in heritable characteristics induced by the environment as “Lamarckian inheritance”.

One, Lamarck did not think that the environment imposed direct effects on organisms that were then passed on. He argued that the environment created needs to which organisms responded by using some features more and others less, that this resulted in those features being accentuated or attenuated, and that this difference was then inherited by offspring. As he wrote,

It is now necessary to explain what I mean by this statement: The environment affects the shape and organization of animals, that is to say that when the environment becomes very different, it produces in the course of time corresponding modifications in the shape and organization of animals. It is true, if this statement were to be taken literally, I should be convicted of an error; for, whatever the environment may do, it does not work any direct modification whatever in the shape and organization of animals. [Translated as in Kampourakis and Zogza (2007)]

What people insist on dubbing “Lamarckian inheritance” in the context of epigenetics is actually closer to the view held by Darwin than by Lamarck. In the second part of his 1858 joint paper with Wallace (excerpted from an 1857 letter to Asa Gray), Darwin wrote,

Selection acts only by the accumulation of slight or greater variations, caused by external conditions, or by the mere fact that in generation the child is not absolutely similar to its parent.

Now take the case of a country undergoing some change. This will tend to cause some of its inhabitants to vary slightly—not but that I believe most beings vary at all times enough for selection to act on them. Some of its inhabitants will be exterminated; and the remainder will be exposed to the mutual action of a different set of inhabitants, which I believe to be far more important to the life of each being than mere climate.

We can read similar things in the Origin:

I have hitherto sometimes spoken as if the variations—so common and multiform in organic beings under domestication, and in a lesser degree in those in a state of nature—had been due to chance. This, of course, is a wholly incorrect expression, but it serves to acknowledge plainly our ignorance of the cause of each particular variation. Some authors believe it to be as much the function of the reproductive system to produce individual differences, or very slight deviations of structure, as to make the child like its parents. But the much greater variability, as well as the greater frequency of monstrosities, under domestication or cultivation, than under nature, leads me to believe that deviations of structure are in some way due to the nature of the conditions of life, to which the parents and their more remote ancestors have been exposed during several generations. I have remarked in the first chapter—but a long catalogue of facts which cannot be here given would be necessary to show the truth of the remark—that the reproductive system is eminently susceptible to changes in the conditions of life; and to this system being functionally disturbed in the parents, I chiefly attribute the varying or plastic condition of the offspring. The male and female sexual elements seem to be affected before that union takes place which is to form a new being. In the case of “sporting” plants, the bud, which in its earliest condition does not apparently differ essentially from an ovule, is alone affected. But why, because the reproductive system is disturbed, this or that part should vary more or less, we are profoundly ignorant. Nevertheless, we can here and there dimly catch a faint ray of light, and we may feel sure that there must be some cause for each deviation of structure, however slight.

Two, the idea of inheritance of acquired characteristics predates Lamarck, was the dominant view in his time, and remained common long afterward. As Morse (1903) wrote,

Jean Lamarck first used the term “acquired character” to designate characters such as these and to him are are we to look for the first clear statement of the case. By this it is not to be understood that the idea of the transmission of acquired characters arose with Lamarck. No great generalization ever arose or ever can arise with one man alone. The attribution of the idea of the transmission of acquired characters to Lamarck falls in the same category as attributing evolution to Darwin.

Zirkle (1946) was more forceful yet,

What Lamarck really did was to accept the hypothesis that acquired characters were heritable, a notion which had been held almost universally for well over two thousand years and which his contemporaries accepted as a matter of course, and to assume that the results of such inheritance were cumulative from generation to generation, thus producing, in time, new species. His individual contribution to biological theory consisted in his application to the problem of the origin of species of the view that acquired characters were inherited and in showing that evolution could be inferred logically from the accepted biological hypotheses. He would doubtless have been greatly astonished to learn that a belief in the inheritance of acquired characters is now labeled “Lamarckian,” although he would almost certainly have felt flattered if evolution itself had been so designated.

Darwin, like Lamarck, invoked use and disuse and inheritance of acquired changes1; the Origin includes an entire section on it, the first part of which reads,

Effects of Use and Disuse.—From the facts alluded to in the first chapter, I think there can be little doubt that use in our domestic animals strengthens and enlarges certain parts, and disuse diminishes them; and that such modifications are inherited. Under free nature, we can have no standard of comparison, by which to judge of the effects of long-continued use or disuse, for we know not the parent-forms; but many animals have structures which can be explained by the effects of disuse. As Professor Owen has remarked, there is no greater anomaly in nature than a bird that cannot fly; yet there are several in this state. The logger-headed duck of South America can only flap along the surface of the water, and has its wings in nearly the same condition as the domestic Aylesbury duck. As the larger ground-feeding birds seldom take flight except to escape danger, I believe that the nearly wingless condition of several birds, which now inhabit or have lately inhabited several oceanic islands, tenanted by no beast of prey, has been caused by disuse. The ostrich indeed inhabits continents and is exposed to danger from which it cannot escape by flight, but by kicking it can defend itself from enemies, as well as any of the smaller quadrupeds. We may imagine that the early progenitor of the ostrich had habits like those of a bustard, and that as natural selection increased in successive generations the size and weight of its body, its legs were used more, and its wings less, until they became incapable of flight.

As was argued by Parkyn (1911),

It is difficult to understand how anyone well acquainted with Darwin’s works can come to any other conclusion than that he firmly believed in Lamarck’s principle of the transmission of characters acquired by use.

Designating epigenetics as Lamarckian greatly misconstrues what Lamarck actually argued. The parts of Lamarckian theory to which it does refer were likewise part of early Darwinian theory. In short, there is no vindication of Lamarck’s mechanism to be granted by epigenetics. That said, there is no doubt that Lamarck’s contributions to evolutionary thinking should be better appreciated. Certainly, the first step toward this would be an effort to understand what he actually proposed.

Updated notes:
1) See the comments discussion. Wilkins has pointed out that Darwin was not simply a “Lamarckian” in terms of new traits arising through need+use/disuse (rather, he suggested that the strength of inheritability of traits is affected by use). However, Darwin did invoke disuse as a reason that traits could be lost which is enough to show that he did not throw out use and disuse as a mechanism of trait change.

Darwin’s note on higher and lower.

Here is a page from Darwin’s 1837 notebook. (Click for larger image)

In case you can’t read his handwriting (few can), it says

It is absurd to talk of one animal being higher than another. We consider those, when the cerebral structure / intellectual faculties most developed, as highest. A bee doubtless would when the instincts were.

Get your Darwin Year gear here.

Did Darwin delay?

In my evolution course, I note that "Darwin spent 20 years working out his ideas and gathering evidence" before releasing On the Origin of Species in 1859. I don't say he "delayed" publication purposely, though in many cases this long period from idea to outcome has been attributed to fear of the reaction from the clergy, colleagues, society at large, his wife, etc. On this issue, a few bloggers have pointed to a recent essay by John van Wyhe (2007), in which it is argued that there was no delay based on fear, only a protracted writing period. Other historians do not necessarily agree, though the blogs I saw did not mention this. As Odling-Smee (2007) says,

…several Darwin scholars are not convinced. Kohn and others agree that the way in which cultural and social pressures influenced Darwin's decisions may have been overplayed, particularly in the public arena, with less attention being paid to the involved process of scientific discovery. But the consensus in the field is likely to remain that a multitude of factors underpinned Darwin's delay.

Kohn points out that searching for explicit references to a "delay" is a simplistic approach to the problem, and that other factors should be considered. For example, Darwin often criticized religion in his notebooks, which suggests that he would have been aware of the probable implications of his theory for religion. It is hard to see how the absence of specific references to a delay rules out any influence of cultural and societal factors on Darwin's decisions, agrees David Quammen, author of The Reluctant Mr Darwin.

Kohn also points out that in Darwin's later publication The Descent of Man, which applied the theory of evolution to humans, Darwin specifically states in the opening lines that he delayed publishing this tome until he was convinced that the climate was right. It seems likely, therefore, that he would have been aware of the controversy his theories would cause from the outset, and probably avoided discussing humans in Origin of Species for this reason.

I think "yes or no" to the question of whether Darwin delayed publication out of fear is very simplistic. Anyone who has written anything of substance knows that sometimes the effect of fear of reaction is procrastination and/or excessive desire to include every piece of information available. Both can cause writing to take longer than it otherwise would. Was Darwin thorough? Yes. Is that one reason it took so long? Undoubtedly. Was he so thorough because of a fear of reaction? Probably at least in part.


Odling-Smee, L. 2007. Darwin and the 20-year publication gap. Nature 446: 478-479.

Van Wyhe, J. 2007. Mind the gap: did Darwin avoid publishing his theory for many years? Notes and Records of the Royal Society 61: 177-205.



Natural selection before Darwin.

Charles Darwin (1809-1882) opened his first notebook about "the species question" in 1837, not long after his return from the voyage of the Beagle. By 1838, he had developed the basic outline   of his theory of natural selection to explain the evolution of species. He spent the next 20 years developing the theory and marshaling evidence in favour of both the fact that species are related through common descent and his particular theory to explain this. After receiving word that another naturalist, Alfred Russel Wallace (1823-1913), had independently come upon the same theory, he assembled his work for publication, first in a joint paper with Wallace presented to the Linnean Society of London in 1858 and then his "abstract", On the Origin of Species, in 1859.

Some authors have argued that Edward Blyth (1810-1873), an acquaintance of Darwin's, developed the central idea of selection in an 1835 paper in the Magazine of Natural History. For example, Eiseley and Grote (1959) claimed that "the leading tenets of Darwin's work — the struggle for existence, variation, natural selection and sexual selection are all fully expressed in Blyth's 1835 paper", from which they then quoted the following:

It is a general law of nature for all creatures to propagate the like of themselves: and this extends even to the most trivial minutiæ, to the slightest individual peculiarities; and thus, among ourselves, we see a family likeness transmitted from generation to generation. When two animals are matched together, each remarkable for a certain given peculiarity, no matter how trivial, there is also a decided tendency in nature for that peculiarity to increase; and if the produce of these animals be set apart, and only those in which the same peculiarity is most apparent, be selected to breed from, the next generation will possess it in a still more remarkable degree; and so on, till at length the variety I designate a breed, is formed, which may be very unlike the original type.

As Eiseley and Grote (1959) and others have noted, however, Blyth's description applies to artificial selection, a process that had obviously been known to breeders long before. In terms of natural selection, Blyth suggested that it would be a conservative and not a creative process, acting to restore the original features modified by artificial selection; that is, it was not a process that caused change, but one that maintained stability within species. Neither Darwin nor Blyth considered this to have been an early example of Darwin's theory of evolution by natural selection (see Schwartz 1974).

Patrick Matthew (1790-1874) did not feel the same way as Blyth, and was vocal in his belief that he had preceded Darwin as, according to calling cards he carried, "Discoverer of the Principle of Natural Selection". In fact, Matthew had proposed an idea similar to natural selection in his 1831 book On Naval Timber and Arboriculture,

There is a law universal in nature, tending to render every reproductive being the best possible suited to its condition that its kind, or organized matter, is susceptible of, which appears intended to model the physical and mental or instinctive powers to their highest perfection and to continue them so. This law sustains the lion in his strength, the hare in her swiftness, and the fox in his wiles. As nature, in all her modifications of life, has a power of increase far beyond what is needed to supply the place of what falls by Time's decay, those individuals who possess not the requisite strength, swiftness, hardihood, or cunning, fall prematurely without reproducing—either a prey to their natural devourers, or sinking under disease, generally induced by want of nourishment, their place being occupied by the more perfect of their own kind, who are pressing on the means of subsistence . . .

There is more beauty and unity of design in this continual balancing of life to circumstance, and greater conformity to those dispositions of nature which are manifest to us, than in total destruction and new creation . . . [The] progeny of the same parents, under great differences of circumstance, might, in several generations, even become distinct species, incapable of co-reproduction.

Darwin, like most others, was not aware of Matthew's book and he learned of it in 1860 when Matthew wrote a letter to the Gardners' Chronicle and Agricultural Gazette including excerpts from his book in response to a review of Darwin's On the Origin of Species.

In your Number of March 3d I observe a long quotation from the Times, stating that Mr. Darwin "professes to have discovered the existence and modus operandi of the natural law of selection," that is, "the power in nature which takes the place of man and performs a selection, sua sponte," in organic life. This discovery recently published as "the results of 20 years' investigation and reflection" by Mr. Darwin turns out to be what I published very fully and brought to apply practically to forestry in my work "Naval Timber and Arboriculture," published as far back as January 1, 1831, by Adam & Charles Black, Edinburgh, and Longman & Co., London, and reviewed in numerous periodicals, so as to have full publicity in the "Metropolitan Magazine," the "Quarterly Review," the "Gardeners' Magazine," by Loudon, who spoke of it as the book, and repeatedly in the "United Service Magazine" for 1831, &c. The following is an extract from this volume, which clearly proves a prior claim.

In a reply in the same magazine, Darwin said,

I freely acknowledge that Mr. Matthew has anticipated by many years the explanation which I have offered of the origin of species, under the name of natural selection. I think that no one will feel surprised that neither I, nor apparently any other naturalist, has heard of Mr. Matthew's views, considering how briefly they are given, and that they appeared in the Appendix to a work on Naval Timber and Arboriculture. I can do no more than offer my apologies to Mr. Matthew for my entire ignorance of his publication.

In terms of arguments that Matthew's contribution diminishes that of Darwin, I tend to agree with Peter Bowler, who said in his book Evolution: The History of an Idea,

Such efforts to denigrate Darwin misunderstand the whole point of the history of science: Matthew did suggest a basic idea of selection, but he did nothing to develop it; and he published it in the appendix to a book on the raising of trees for shipbuilding. No one took him seriously, and he played no role in the emergence of Darwinism. Simple priority is not enough to earn a thinker a place in the history of science: one has to develop the idea and convince others of its value to make a real contribution. Darwin's notebooks confirm that he drew no inspiration from Matthew or any of the other alleged precursors.

In any case, neither Blyth nor Matthew was the first to propose natural selection in very basic form. Another individual, an American physician of Scottish descent by the name of William Charles Wells (1757-1817), presented a paper in 1813 (published in 1818) that included a process of natural selection to account for differences in skin colour among people. Wells considered light skin to be the primitive condition, with dark skin a subsequent specialization.

Again, those who attend to the improvement of domestic animals, when they find individuals possessing, in a greater degree than common, qualities they desire, couple a male and female of these together, then take the best of their offspring as a new stock, and in this way proceed, till they approach as near the point in view, as the nature of things will permit. But, what is here done by art, seems to be done, with equal efficacy, though more slowly, by nature, in the formation of varieties of mankind, fitted for the country which they inhabit. Of the accidental varieties of man, which would occur amnog the first few and scattered inhabitants of the middle regions of Africa, some one would be better fitted than the others to bear the diseases of the country. This race would consequently multiply, while the others would decrease, not only from their inability to sustain the attacks of disease, but from their incapacity of contending with their more vigorous neighbours. The colour of this vigorous race I take for granted, from what has been already said, would be dark. But the same disposition to form varieties still existing, a darker and a darker race would in the course of time occur, and as the darkest would be the best fitted for the climate, this would at length become the most prevalent, if not the only race, in the particular country in which it had originated.

Darwin added an acknowledgment of Wells's work beginning with the 4th edition of the Origin in 1866,

In 1813 Dr. W.C. Wells read before the Royal Society 'An Account of a White Female, part of whose Skin resembles that of a Negro;' but his paper was not published until his famous 'Two Essays upon Dew and Single Vision' appeared in 1818. In this paper he distinctly recognises the principle of natural selection, and this is the first recognition which has been indicated; but he applies it only to the races of man, and to certain characters alone.

What Darwin (and until recently, most historians) did not realize was that the general notion of selection had already been proposed by 1794. In an review in Nature in 2003, Paul Pearson pointed out that James Hutton (1726-1797), considered the Father of Modern Geology, postulated something similar to natural selection in An Investigation of the Principles of Knowledge. (Pearson also noted the interesting bit of trivia that Hutton, Wells, Matthew, and Darwin all attended the University of Edinburgh).

As Hutton (1794) said,

 …if an organised body is not in the situation and circumstances best adapted to its sustenance and propagation, then, in conceiving an indefinite variety among the individuals of that species, we must be assured, that, on the one hand, those which depart most from the best adapted constitution, will be most liable to perish, while, on the other hand, those organised bodies, which most approach to the best constitution for the present circumstances, will be best adapted to continue, in preserving themselves and multiplying the individuals of their race.

Now, if those organised bodies shall thus multiply, in varying continually according to the particular circumstances in which are found the necessary conditions for their life and propagation, we might expect to see, in this world, a variety in the species of things, which we might term a race; varieties which do not affect the species of things, but which, upon many occasions, might appear to us as being a different race of the same species, whether of plant or animal. But, such things are every where observed; consequently, we have reason to conclude, it is truly in this manner, that are naturally produced those various races of plants and animals, which we find naturally upon the surface of this earth. Each of those races of things, therefore, would appear to us to be wisely calculated, by nature, for the purpose of this world.

Hutton used the examples of fast running and a strong sense of smell in dogs to illustrate the mechanism. He did not, however, accept the notion that new species could form by this or any process. For Hutton, this was limited to creating varieties only and not species.


It is important to note that Darwin himself recognized that others had discovered natural selection at least in basic outline before (and after) he had. He did not avoid sharing credit to the extent that it was due. In light of this history, one could argue that because natural selection as a mechanism had been proposed by several authors that it would have been discovered and recognized as important eventually, even without Darwin's input — and, indeed, it probably would have, as would Newton's laws of motion, Einstein's theory of relativity, and other fundamental principles describing the natural world. On the other hand, the idea had been around for at least six decades before Darwin published the Origin, and it was not until someone of Darwin's genius developed the idea that evolution assumed its position as the underlying theme of all biology.


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