Ask A Biologist
We've teamed up with the experts at ASU Ask a Biologist and Dr. Biology to answer some of your interesting and unusual questions about Darwin and evolution, including ones from our lectures that we aren't able to get to. Check out our Q&A here!
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Monday
Oct122009

Q&A from first lecture with Prof Everett Mendelsohn

We've teamed up with the experts at ASU Ask a Biologist and Dr. Biology to answer some of your interesting and unusual questions about Darwin and evolution, including ones from our lecture series that we aren't able to get to in the allotted time.

Here's our first installment of answers to questions from our first lecture "World Before Darwin" with Harvard Professor Everett Mendelsohn. (If you missed it live, watch the webcast or listen to the mp3.)

 

1. If Darwin had never written Origin of Species, would we today be celebrating Wallace-ism? 

This is an example of what historians call a counter-factual, an exercise in imagining what might have been had something not happened. Counter-factuals are notoriously difficult to resolve but there are some facts that we can bring to the table. A number of individuals (not just Wallace) had conceptualized natural selection by the time Darwin received the Wallace manuscript in 1858. None of these (other than Wallace) had seen selection as a positive evolutionary force. While Wallace co-discovered the mechanism, he did not have the network of allies and colleagues that Darwin had and these certainly aided the spread of "Darwinism." This latter term is in quotations because, while Darwin and his colleagues (including Thomas Henry Huxley) succeeded in convincing the scientific community of the fact of evolutionary change, they did not succeed in convincing the community of Darwin's (and Wallace's) mechanism of natural selection. This would only widely occur in the 1930's, approximately 60 years later. Indeed Wallace was one of the few individuals who saw the power of selection (although he denied its ability to shape the human mind). So despite his network of supporters, Darwin was unable to fully convince others of natural selection's power and thus I'm willing to guess Wallace would have been unlikely to have either. Whether "Wallaceism" would have become accepted any later than "Darwinism" is a question best left to late night conversation over refreshing beverages. 

John Lynch (answering for Ask A Biologist)

Principal Lecturer

ASU Barrett, The Honors College & School of Life Sciences 
  

2. How did Darwin interrelate w/ discussions of Eugenics in those days. Did he develop a stance (personal conviction) on eugenics? 

Darwin's relationship with eugenics can be most clearly seen in the last chapter of his work The Descent of Man. While clearly seeing that eugenic procedures made sense if we were to conceptualize humans as being like livestock, he clearly felt that such procedures were to be resisted because they would go against "the noblest part of our nature". As he stated: 

"The aid which we feel impelled to give to the helpless is mainly an incidental result of the instinct of sympathy, which was originally acquired as part of the social instincts, but subsequently rendered, in the manner previously indicated, more tender and more widely diffused. Nor could we check our sympathy, even at the urging of hard reason, without deterioration in the noblest part of our nature. The surgeon may harden himself whilst performing an operation, for he knows that he is acting for the good of his patient; but if we were intentionally to neglect the weak and helpless, it could only be for a contingent benefit, with an overwhelming present evil. Hence we must bear without complaining the undoubtedly bad effects of the weak surviving and propagating their kind." 

John Lynch (answering for Ask A Biologist)

Principal Lecturer

ASU Barrett, The Honors College & School of Life Sciences 
 

3. How long did it take from the publication of the Origin for the theory to become mainstream within the growing scientific profession?  Did it take a spokesperson or did it spread by word of mouth? 

There are many separate proposals in “Darwinism” (in the narrow, historical sense of what Darwin argued), and how quickly they were each accepted varied. The overarching idea – that of organic evolution, with all life being related through common descent – was accepted by many of Darwin’s peers quite rapidly.  Darwin was not the first to argue in favor of “transmutation”, an idea that some had argued for more than a century before Darwin wrote “On the Origin of Species by Means of Natural Selection” in 1859.  But Darwin’s conception of evolution as a branching process with no inherent directionality was new, and in “The Origin of Species”, Darwin pointed out a that a large number of seemingly unconnected facts could be understood as the outcome of the very simple process of descent with modification and diversification.  These included facts of organismal development, the distribution of species, the presence of vestigial features, the fossil record, etc..  The overall argument for the fact of evolution was very powerful, and the recognition of this had the effect that powerful and radical ideas frequently do in science; it was rejected by those with a strong intellectual commitment to the ideas that came before, and seen for what it was by the younger generation of scientists, who built upon it.  The years following “The Origin” saw a flurry of attempts to discredit Darwin’s work, but very little productive science being done outside of an evolutionary framework. This was a remarkably fast acceptance given the preceding century of skepticism about evolution, and is a testament to Darwin’s insight.  However, Darwin’s central mechanism of natural selection had a very different fate.  Most biologists of the time accepted that a process like selection acted to “purify the herd”, eliminating weaker individuals, but few immediately saw that Darwin’s real brilliance lay in showing how this process could lead to significant change over time, and the evolution of intricate adaptations.  It was not, in fact, until the early-middle part of the 20th century that this process was understood and generally accepted as the centerpiece of Darwin’s contribution.

Darwin himself was quiet and ill suited to the task of promoting his ideas in public, and his prominent friends undertook this task, particularly T.H. Huxley. But it was the strength of his ideas as presented in his published work that served as his most effective spokesperson.  It is also important that Darwin spent the 25 years preceding the publication of “The Origin of Species” establishing himself as a scientist of significant stature, fitting himself into the group of people that would serve as the judges of his radical ideas.  His reputation and important social connections served him well, a fact that distinguishes him from most of his predecessors who failed to win acceptance of the idea of biological evolution. 

Dr. Mark Spencer (answering for Ask A Biologist)

Assistant Professor, ASU School of Human Evolution & Social Change 

 

4.  Why was T.H. Huxley critical of "Vestiges"? 

“The Vestiges of the Natural History of Creation” was published anonymously in 1844, and was immensely popular.  It laid out a grand history of life and the universe, all built upon a foundation of law-like evolutionary processes, from star formation to organic diversity.  It brought together many themes that had been discussed in the early part of the 19th century (and earlier) and is generally accepted as having prepared polite Victorian society for the idea of evolutionary change, in contrast to the static world-view that dominated Western thought at the time.  Reading “Vestiges” one is struck by the apparent degree to which it anticipates later scientific developments, particularly those of Charles Darwin regarding the evolution of life.  The work was certainly well-known to Darwin and other naturalists of the time, including Darwin’s friend Thomas Huxley, who generally regarded the book as amateurish.  As with many works of popular science then and now, it was looked down upon by the intellectual leaders of the fields it touched on.  It is tempting to look back at this history and feel that the author of “Vestiges” (later revealed to be a Scottish journalist named Robert Chambers) was not given his proper credit.  However, while the book was very popular and should be seen as having had an important social influence, it offered little scientifically that had not been discussed previously, and did not solve the critical intellectual problems that were later addressed so well by Darwin. The idea of biological evolution had been discussed for nearly a century by natural historians of the enlightenment, and many of the ideas and facts that Darwin drew upon in his work had been established previously. The idea of evolutionary change, however, tended to be associated with radical political elements in society, who adopted it in contrast to the traditional views held by those in power.  This fact was not lost on Darwin, who necessarily had to confront the somewhat unseemly reputation of evolutionary ideas and their history of use by elements of society with which he did not wish to be associated.  He did this through painstaking attention to detail and intellectual rigor, and the amassment of an undeniable body of evidence supporting the idea of evolutionary change.  It was these attributes that “Vestiges” lacked -  Chambers gathered together previously discussed facts and ideas, weaving them into a boldly speculative grand scenario, but he did not address the logical weakness at the heart of evolutionary thinking of the time.  Central to this weakness was the lack of a mechanism of evolutionary change and adaptation.  Chambers invoked the ideas of Lamarck to explain evolutionary change, ideas that had been proposed 40 years prior to “Vestiges” and had been found to be inadequate.  Huxley was himself quite skeptical regarding the concept of evolution prior to his association with Darwin, and in fact never really came to accept the full scope of Darwin’s idea, particularly the creative power of natural selection (which we see in hindsight was the crucial missing mechanism, and Darwin’s major insight).  He did, of course, come to be a most ardent supporter of evolution, and so it seems logical that he would have valued "Vestiges". But, more than anything else, Huxley was a critic of the casual maintenance and inheritance of power by the religious establishment and an advocate for a merit-based society that valued the contributions of science – he spent his life promoting the growth of professionalism in science.  Chambers’ amateur speculation and lack of careful, steady analysis was the kind of science that Huxley fought against.  Chambers’ failure to adequately dissociate his work from radical political groups would also have been seen as a weakness by Huxley.  In short, Huxley was critical of “Vestiges” because he should have been; it was a speculative popular work by a non-professional who benefited from his place in time and the gathering weight of evidence favoring the idea of evolutionary change, but who did little to address the social and scientific problems of importance. 

Dr. Mark Spencer (answering for Ask A Biologist)

Assistant Professor, ASU School of Human Evolution & Social Change 
 
 

5. To what degree can the insistence on gradualism by the English naturalists, including Darwin, be attributed to unconscious resistance to the disasters of the French Revolution? That is, in the bourgeois English way, great change, great effect, great progress can come about through grand, stately gradual change. 

Much has been made of the social influences on Darwin and his contemporaries – from the industrial revolution, with its promise of progress, to Adam Smith’s heartless capitalism, there is little doubt that the social context of the 19th century was conducive to the development of evolutionary ideas.  It is tempting to look at this context as a catalyst for many of the scientific developments of the time, and there was no doubt a strong social influence on the people behind these developments, as there is on all people at all times.  Gradualism, as a way of viewing change in the natural world, may very well have such connections.  But this idea grew out of the scientific process, as well. It is closely associated with Uniformitarianism, both logically and historically. Uniformitarianism is a basic assumption of much of science, and holds that the processes that we see acting around us in the present day are those that acted in the past.  During the Enlightenment, it was the 18th century Scottish Geologist James Hutton who first formulated the idea, and it was central to Sir Charles Lyell’s foundational text on geology in the 19th century.  Both, as geologists, correctly saw the small-scale, slowly acting processes of sedimentation, erosion, etc. as the key to explaining large-scale geological features.  Darwin was strongly influenced by his friend Lyell, and his conception of gradual evolutionary change is clearly based on Lyell’s gradualistic geology.  Among Darwin’s works, in fact, is a classic treatise on the long-term effects on soil of the action of earthworms, a quirky topic that reflects his deep-seated interest in the power of gradual change.  For Lyell and Darwin, gradualism was a scientific conclusion, not a moral imperative.  For Darwin, it was central to his favored mechanism of organic change, natural selection.  It was not just that he assumed selection to operate in a gradual fashion; incremental change was required for selection to act as he argued it did.  This logical dependence on gradualism would have existed without regard to the social context Darwin worked in. It is of interest, however, that Lyell’s work was concerned in large part with overturning the concept of Catastrophism that had been dominant in continental thinking and is attributed to the influencial French zoologist Georges Cuvier.  Cuvier, whose career followed in the wake of the French Revolution, resisted the idea of evolution, but was confronted with the fact of extinct species.  His solution, which mirrored the political events of his time and kept him on good terms with the church, was to suggest that large-scale catastrophies resulted in extinction.  It is tempting to see the stamp of sociopolitical influence on these conclusions about the natural world, and to imagine the stately Sir Charles delighting in overturning French natural history and political thinking simultaneously.  However, in the case of gradualism, there were sound scientific reasons to argue that nature does frequently act slowly, carefully, and incrementally.  

Dr. Mark Spencer (answering for Ask A Biologist)

Assistant Professor, ASU School of Human Evolution & Social Change 

 

6. Why are so many still so afraid of what Darwin had to say? 

In “The Origin of Species,” Darwin’s ideas combine to form a scientific explanation of a phenomenon; Darwin elicited a mechanism by which populations of living organisms change over time and diversify. Darwin proposed that a process called natural selection, which acted by preserving “profitable modifications,” and extinction worked “hand-in-hand” to produce the living forms of his day.  This explanation of Darwin’s is a theory and in science, a theory is well-substantiated by multiple lines of evidence, typically comprising a set of well-tested hypotheses and observations of regularities in nature.  

Few people in the 1800s or today would contest that populations change over time, or, more accurately, few people would argue against the idea that offspring look similar to, but are not identical to parents and that, over multiple generations, “families” change and new variations can appear. Individuals in the 1800s, like Darwin himself, who took an interest in breeding experiments with pigeons, dogs or plants, observed that certain traits could be “selected for” or “selected against” by choosing parents with or without the trait of interest, thus effectively shifting the gene pool of the population toward a particular region of the genotypic and phenotypic spectra (note, however, that genes were unknown entities at the time of the publication of “The Origin of Species”).  Darwin wrote, “The offspring from the first cross between two pure breeds is tolerably and sometimes (as I have found with pigeons) extremely uniform, and everything seems simple enough; but when those mongrels are crossed one with another for several generations, hardly two of them will be alike...” Though breeding experiments are acceptable, even to those of strong religious faith, as a means to select for desired traits within populations of domesticated animals, the idea of nature selecting for desirable traits in the wild (or, more accurately, the idea that traits conferring benefits upon their bearers in a particular environment are more likely to be passed on to offspring) was not well-received by all in the 19th century and still is not accepted by many. Why is this? 

It is true that there are individuals who can be characterized as “fearing” what Darwin had to say, but the heart of the problem for many lies not in what Darwin had to say, or even how he said it, but in the implications of Darwin’s words for the interpretation of our own origins, history and fate and how those interpretations conflict with people’s moral and spiritual beliefs and the teachings of various religions. Some (but not all) of these conflicts are presented below: 

  • Darwin himself was aware of the social upheaval his ideas might cause and kept his written work from the public for decades. In mid-19th century England, Darwin’s thesis contradicted the popular belief that the Earth is relatively young.  Regarding the fossil record, Darwin wrote, “The crust of the earth is a vast museum; but the natural collections have been made only at intervals of time immensely remote.” The idea of an earth that is billions of years old, preserving a record of life spanning billions of years, continues to be a problem for many people who believe that the earth – and humans – have been around for fewer than 6000 – 7000 years.  On his journey on the H.M.S. Beagle, Darwin saw evidence for extinction and the replacement of extinct species by modern species and argued against the idea that all life had been created in the form in which it existed in the 19th century, which opposed many people’s interpretation of the Bible.
 
  • Though Darwin dedicated but one sentence of The Origin of Species to the evolution of humankind, Darwin’s vision of “organic beings…constantly endeavoring to increase in numbers” and gaining advantage of other such beings was tragically used by many to justify the mistreatment of peoples in the 20th century. “Social Darwinism” gave evolution by natural selection a bad reputation and still, to this day, influences some people to incorrectly associate Darwin with Hitler and the horrid actions of the Nazi party during the second World War.
 
  • If one accepts, as Darwin proposed in “The Origin of Species,” all beings as the descendents of some few beings that lived hundreds of millions of years in the past, and are not special creations, the inference must be made that humans are not special creations. This contradicts the belief that humankind is the special creation of a supernatural being such as the Christian God.  The anthropocentric idea of humankind as the “pinnacle” of evolution is also challenged by the idea that humans have evolved from the same organisms as other living beings.  The idea that there is a common ancestor of humans and other mammals, or humans and other vertebrates, makes us “just animals” and it is challenging for some people to accept our place in nature.  People of many faiths challenge the idea, especially, that humans and modern apes (chimpanzees, gorillas, orangutans and gibbons) share a relatively recent common ancestor. In response to a recent scientific article on the web about a group of newly described fossils belonging to a human ancestor, one internet user wrote, “The reason no missing link has ever been found is because there is no link between man and ape. We humans are created in the image of God. Evolution is rubbish.” Another wrote, “We Muslims believe that the origin of man is man and not a monkey or another animal.”
 
  • Some people (who may or may not be associated with religious groups) have problems with the mechanism that Darwin proposed for how evolution occurs. Darwin himself, in “The Origin of Species,” acknowledged that it seemed “absurd” to imagine that complex structures, such as the eye, could come to be via evolution by natural selection; this is the basis of the argument made by Intelligent Design supporters. However, Darwin explained that, through reason, one can recognize the progression of an eye from an imperfect, simple structure to one more complex and perfect.  One reason why some people may have problems accepting Darwin’s mechanism is it requires that one be able to fathom extremely long expanses of time – hundreds of millions of years -- which is challenging for many people.   
 

Were he alive today, Darwin would be surprised to discover the discourse that still surrounds the content of his most famous of scientific manuscripts, especially given what we know today about the role of genetics in evolutionary biology. Scientists have gathered evidence for other mechanisms of evolution, such as gene flow, genetic drift and mutation, which contribute to science’s explanation for how the phenomenon of biological evolution occurs.  

Despite the evidence collected by naturalists and scientists to explain how the fact of biological evolution occurs, the application of these mechanisms to humankind challenges the precepts of many spiritual organizations and will, therefore, undoubtedly, continue to face challenges throughout humankind’s future.  

Caitlin Schrein (answering for Ask A Biologist)

PhD Candidate Doctoral Candidate, ASU School of Human Evolution and Social Change

Stay tuned for answers to questions from our second lecture on "Variation" with Pulitzer-Prize winner Jonathan Weiner. Missed it? Listen to the podcast here.