News of the Death of the Tree of Life Has Been Greatly Exaggerated

A Report by
Steven Schafersman, Ph.D.
Texas Citizens for Science
2009 February 7

On 2009 January 22, Texas State Board of Education member Barbara Cargill told the audience in the Travis Building hearing room in Austin that there have been recent "significant challenges" to evolution that rejected Darwin's "Tree of Life." The "Tree of Life" is a metaphor--with an underlying branching or tree-like reality--that Darwin used to represent the common ancestry (or common descent) of all organisms that he hypothesized to exist if his hypothesis of evolution was true.  Today, the Tree of Life could be termed the phylogeny of life, since the word tree is the common name for the scientific term phylogeny and other branching diagrams that depict the biological evolution and diversification of clades and lineages of organisms.

Cargill stated that an article she read or read about (she wasn't clear which) reported that a European scientist disputed Darwin's "Tree of Life,"  implying that it was "wrong and misleading." To her mind, this article proved that her amendment to Earth and Space Science Student Expectation 8A--which requires that students must "assess the arguments for and against universal common descent"--had merit. On February 4, a reporter wrote about Ms. Cargill: "She pointed to herself reading a current article about the strengths and weaknesses some experts have found with Charles Darwin’s theories and how curriculum changes would make it difficult to include this information in a lesson plan..."

Although Barbara Cargill did not state the source, we know that the recent news article in question was in the 2009 January 21 New Scientist, and some of its claims were repeated in The Telegraph the next day. The Telegraph's headline provocatively claimed, "Charles Darwin's tree of life, which shows how species are related, is 'wrong' and 'misleading', claim scientists." I was in the hearing room in Austin when she made her statement, live blogging the meeting, and I wondered what she was talking about, since I was unaware of any such article about evolutionary trees. I took the time that night to find the article using Google, read it immediately, and was both surprised and angry. The issue of New Scientist (NS) that contains the article has a large tree on the front cover with the words "Darwin was wrong."

Is it true that Darwin was wrong about the Tree of Life he proposed? Yes and no. Yes in a meaningless sense, not in the way implied by the very misleading NS cover, subtitle ("Cutting down the tree of life"),  and article. Darwin's Tree of Life still very much exists, but in a different form than he knew or could know, since it has been revised by recent and dramatic increases in modern genetic knowledge. Is it true that a "significant challenge" has been made to Darwin's Tree of Life? Yes again, but this "challenge" is to the details of part of the tree brought about by discoveries of genetic information that Darwin did not have and could not possibly have known, so it's really quite irresponsible to claim that "Darwin was wrong" when he was essentially right and now new knowledge has changed our image of the tree of life. In addition, this challenge is old news: the traditional Tree of Life was revised almost a decade ago. A much better and scientifically-accurate article about this revision was published in 2000, and NS adds nothing new.

Is it true that depictions of the Tree of Life are "wrong and misleading"? Yes and no. Darwin's original 1859 understanding of the Tree of Life was inaccurate, but not through any fault of his own; its traditional representations should not be used today. Modern depictions of the Tree of Life are neither wrong nor misleading (one still accurate representation was published in the 2000 paper).

As we will see, for the most part the two news articles were sensationalistic and misleading. They were heavily criticized by evolutionary scientists within days of their publication in several ways. The scientists stated that the articles (1) were old news, probably being published to coincide with the upcoming 200th anniversary of Darwin's birth and 150th anniversary of the publication of the Origin of Species, (2) were unnecessarily sensationalistic, (3) gave Creationists an undeserved excuse to trumpet their common antipathy to common descent, and (4) were scientifically inaccurate when one analyzes some of the quoted statements they contain. Graham Lawton, the author of the New Scientist article, came in for especially heavy criticism since the original misleading article was his responsibility.

But the most important question from the standpoint of Texas science standards is this: Does the alleged death or rejection of Darwin's Tree of Life as reported in the two news articles mean that common ancestry is in dispute? Most certainly not. Our improved understanding of the phylogeny of living organisms has only increased scientists' confidence in the fact of common ancestry (or common descent). The Tree of Life is even better understood now, and life's common ancestry even better mapped out. SBOE member Barbara Cargill did not understand the meaning of the news article she read or read about. She assumed from the vaguest information--probably provided to her by a Creationist blogger or email message--that the news article demonstrated that the Tree of Life was dying or dead, and this spelled the end of common descent. But her lack of biological knowledge and Creationist bias prevented her from realizing that the opposite was true. Then, she presented her false characterization of the true story to her fellow State Board members, in effect fooling them to get her anti-scientific amendment approved. This is obviously the wrong way for state education policy to be formulated: persuade your colleagues to vote for your amendment by deceiving them. But as I have written before, pseudosciences such as Creationism are enterprises that try to convince listeners and readers by deceiving them, since sophistry is their main strategy and specious arguments their main tactic.

First let's examine the origin of the Tree of Life metaphor. In July, 1837, Charles Darwin drew the first evolutionary tree in scientific history in his Transmutation Notebook B:

 

This drawing is quite famous and has been reproduced widely; for example, a schematic copy has been used as the National Center for Science Education logo since 2007:

In his November, 1859, Origin of Species (title page below), Darwin proposed that as a consequence of evolution, the pattern of common descent could be represented as a "great tree."

He even included a hypothetical example of a tree as a figure, the only diagram in the book, reproduced below:

Darwin's tree showed several different branching patterns that Darwin believed represented the different patterns of evolution that he could discern from the living and fossil records. He described the Tree of Life in the text of the Origin:

"The affinities of all the beings of the same class have sometimes been represented by a great tree. I believe this simile largely speaks the truth. The green and budding twigs may represent existing species; and those produced during each former year may represent the long succession of extinct species." p. 129

"As buds give rise by growth to fresh buds, and these, if vigorous, branch out and overtop on all sides many a feebler branch, so by generation I believe it has been with the great Tree of Life, which fills with its dead and broken branches the crust of the earth, and covers the surface with its ever branching and beautiful ramifications." p. 130

"This gradual increase in number of the species of a group is strictly conformable with my theory; as the species of the same genus, and the genera of the same family, can increase only slowly and progressively; for the process of modification and the production of a number of allied forms must be slow and gradual,—one species giving rise first to two or three varieties, these being slowly converted into species, which in their turn produce by equally slow steps other species, and so on, like the branching of a great tree from a single stem, till the group becomes large." p. 317

Darwin's hypothesis of evolution (he termed it a "theory") had several parts. One part was a hypothesis about species diversification; Darwin called it descent with modification. It was this part that Darwin visualized as and illustrated with a tree. As taxa evolve, they split and diversify through time, increasing taxonomic diversity. Of course, the tree was just an image or metaphor for the real thing, or underlying reality as I have described it above. The tree image represents it well: a major aspect of evolution involves the splitting of lineages and the generation of greater numbers of clades. Other aspects of evolution that can also be represented by trees are the gradual change through time of a lineage, the stasis of a lineage, and the extinction of a lineage. Darwin tried to represent all four aspects on his busy tree. Most trees today, termed cladogenetic trees, depict only the splitting of taxa and lineages, since this data can most readily be determined by both morphological and molecular investigation of the shared and derived features of living and fossil organisms. Investigation of the other three aspects are mostly restricted to fossil organisms.

This figure is one of the most important diagrams in the history of science. Darwin illustrates cladogenetic (punctuated) change, anagenetic (gradual) change, stasis, and extinction, all patterns we continue to infer today among different taxa. The concept of evolutionary trees and the Tree of Life are closely associated with Darwin and with the process of evolution. Darwin was as much a geologist and paleontologist as he was a biologist, so his knowledge of the fossil record was the equal of any paleontologist of his day. While the fossil record in his day did not provide proof of evolution--but as did, for example, by the embryological, biogeographical, anatomical, and systematic evidence that Darwin emphasized in the Origin--Darwin certainly interpreted the known fossil record as a consequence of evolution in a way that made sense of it for the first time in science. Unlike modern trees that show the relationships of primitive and derived characters and in a timeless perspective, the vertical axis of Darwin's tree represents time and the horizontal axis represents morphology, just as evolutionary phylogenies of fossils have long been illustrated.

The great antipathy that Creationists have to Darwin's Tree of Life--as expressed in the pseudoscientific and polemical materials from Young Earth Creationists and Intelligent Design Creationists such as the Discovery Institute--may be due to their belief that Darwin expropriated the term from Genesis and gave it a new and dangerous evolutionary meaning. The Tree of Life in the Garden of Eden described in the Bible's Book of Genesis has enormous Christian mythological significance, for eating the fruit of this tree--which was permitted for Adam and Eve by God--gave them eternal life. They were commanded to not eat the fruit of the Tree of Knowledge of Good and Evil, but unfortunately, not having that specific knowledge, they disobeyed God's command and he quite unfairly and cruelly expelled them from the Garden of Eden. Being thus expelled, they could no longer eat the fruit of the Tree of Life and thus became mortal (although still very, very long-lived!) and suffered death. Christianity promises life after death as one of its doctrines of the faith--probably the central doctrine of Christianity, since concern about death is a prime motivator of religious belief. To Creationists, therefore, misappropriating the term "Tree of Life" for an evolutionary metaphor that replaces a central Christian metaphor--which they believe Darwin did--would be an enormous insult to their religion. It is not known if Darwin even considered the fact that the term "Tree of Life" had a long-standing Christian metaphorical and mythical meaning of great significance and that using the term in an evolutionary context might insult them. The prospect that he used the term deliberately for this reason is fascinating, but the truth is probably that he did not consider this aspect.

The concept of phylogenetic tree is very important in modern biosystematics, the study of the diversity of life. There are several different types of evolutionary trees. This is not the place to discuss the differences in detail, but here are graphics of four different trees:


 Universal and Eukaryotic trees


A Simplified Universal Tree


A Eukaryotic Tree

 
A Hominid Tree

The first three trees are cladogenetic trees in which the branches represent differences in shared and uniquely derived characters and show the locations of common ancestors but not direct ancestors. Only the hominid tree has time on the vertical axis and shows direct ancestors. The first three trees are typical of modern biosystematics since they are fully reproducible if the same characters and computation method are used, whereas the hominid tree is not considered to be good practice because the inference of direct ancestors has subjective elements that is not reproducible and may not be accurate. However, both types are commonly found in scientific publications and textbooks, the last less commonly now. It is still common to find phylogenetic trees with stratomorphometric data of fossil organisms in the scientific literature, but typically now different taxa are not represented as being in direct ancestry, but rather sharing common ancestry. The point of this discussion is that evolutionary trees are common in the scientific literature today, they are widely used by molecular, phenotypic, and paleontological systematists, and most of them look like traditional trees, with roots and branching clades and lineages.

Next, let's take a look at the two news articles. The Telegraph took its story from the NS article, and both contain the same fairly outrageous quotes and claims (Graham Lawton is the source unless otherwise indicated):

  1. Evolution is far too complex to be explained by a few roots and branches, they claim.
  2. But today the project [tree of life] lies in tatters, torn to pieces by an onslaught of negative evidence.
  3. Dr. Eric Bapteste: We have no evidence at all that the tree of life is a reality.
  4. By the mid-1980s there was great optimism that molecular techniques would finally reveal the universal tree of life in all its glory. Ironically, the opposite happened.
  5. "As early as 1993, some were proposing that for bacteria and archaea the tree of life was more like a web. In 1999, Doolittle made the provocative claim that "the history of life cannot properly be represented as a tree" (Science, vol 284, p 2124). "The tree of life is not something that exists in nature, it's a way that humans classify nature," he says."
  6. Dr. John Dupré: If there is a tree of life it's a small irregular structure growing out of the web of life.
  7. Dr. John Dupré: Our standard model of evolution is under enormous pressure.
  8. Dr. Michael Rose: The tree of life is being politely buried – we all know that. What's less accepted is our whole fundamental view of biology needs to change.
  9. Surprisingly, HGT [horizontal gene transfer] also turns out to be the rule rather than the exception in the third great domain of life, the eukaryotes. For a start, it is increasingly accepted that the eukaryotes originated by the fusion of two prokaryotes, one bacterial and the other archaeal..."
  10. Having uprooted the tree of unicellular life, biologists are now taking their axes to the remaining branches.
  11. Some researchers are also convinced that hybridisation has been a major driving force in animal evolution, and that the process is ongoing....This is especially true in rapidly evolving lineages with lots of recently diverged species...

These sentences are either untrue or misleading:

  1. True but absurd; no evolutionary biologist has ever claimed that evolution can be explained by a "few roots and branches." The first tree ever published --in Darwin's Origin of Species--had many roots and branches, not a few.
  2. False. The Tree of Life project is stronger and more accurate than ever.
  3. Absolutely false. The tree of life is a metaphor for an underlying reality: the common ancestry of all life.
  4. False. Modern molecular techniques have altered and greatly improved the universal tree of life.
  5. It is true that the "tree" for bacteria and archaea is more like a web (or net, bush, thicket). Indeed, the complete history of life can no longer be represented as just a tree. For prokaryotes it is a web and for eukaryotes it is a tree, but in both cases it is a reticulated, anastomosing, or branching diagram that represents the underlying reality of genetic and evolutionary connection. The tree of life exists in nature as a metaphor or representation of the reality of common ancestry.
  6. A false metaphor. The plants and animals we usually see, the eukaryotes, have a phylogeny that can be represented as an enormous tree of life. But it's base does indeed grow out of a web (or net, thicket, bush) of life, something more complex than the eukaryotic tree.
  7. A misrepresentation. The standard model of evolution has extremely high scientific consensus, but of course it is incomplete and will be modified by additional hypotheses. It is under no more pressure than anything else in science.
  8. False and an exaggeration. The tree of life is being modified, not buried. Our fundamental view of biology does not need to change any more than it has changed over the decades. It has always been changing and will continue to change gradually as new information appears.
  9. False. Horizontal gene transfer (HGT) is certainly not the rule in eukaryotes. Eukaryotes did originate by HGT, but in subsequent evolution eukaryotes have specialized using vertical gene transfer (VGT) since they evolved and possess discrete germ cells. It is true that many unicellular eukaryotes (protists, protozoa, and protophytans) do engage in some HGT, but nothing like the prokaryotes.
  10. Not true. While true for the first clause, traditional eukaryotic trees are still well-accepted.
  11. All true, but the author tries to make the occurrence of eukaryotic hybridization a reason to "uproot" or "cut down" the eukaryotic trees, and this is just nonsense. Fertile hybridization operates with very closely-related species--which have essentially the same genes--so there is reason to say that phylogenetic trees are threatened by these species. But, eventually hybrids become sterile as species differentiation accentuates, and hybridization for the vast majority of eukaryote species in trees quickly becomes a non-issue.

Graham Lawton, the author of the NS article, is primarily to blame for the exaggeration, sensationalism, and misrepresentations in it. New Scientist has done this before, with positive and credulous news stories about Roger Shawyer (Em Drive) and Rupert Sheldrake (formative causation and morphogenic fields). But this was not inevitable. New Scientist often produces scientifically-accurate articles about evolution, such as "Evolution: What missing link?" in February, 2008, by paleontologist Donald Prothero, and The Telegraph correctly reported on this article in a news story by Lucy Cockcroft the next day without exaggeration and sensationalism. I myself found the NS story later on the day (January 22) when Barbara Cargill first mentioned it. I read it and realized how bad it was for many reasons. I did not write about it that day, since I was still live blogging the State Board meetings in Austin and I didn't have my usual documentary resources and waited until I traveled home. However, many evolutionary biologists were outraged when the NS article and cover appeared, and the evolution blogs immediately responded. Here are some of the main ones that covered this story:

The Trouble With Science Journalism

If the article, by Graham Lawton, had some real news to report that would justify such a headline, then that would be one thing. In reality, though, the article has only the yawn-worthy old-news that horizontal gene transfer among single-celled organisms means that the metaphor of a tree of life must be modified. Scientific American published a far more informative version of the same article back in February of 2000.

Of course, it wasn't the tree metaphor itself that was so crucial, at least not those parts of a tree that distinguish it from a web. It was the idea of descent with modification that was critical. And the tree metaphor still works very well for animal evolution.

For the scientifically-curious layperson interested in the major points of evolutionary theory, there is nothing in this article that merits more than a shoulder-shrug.

I have no doubt the editors of New Scientist are patting themselves on the back for their courage in putting so provocative a headline on their cover. They are not the ones who will have to deal with this new creationist talking point....In short, this is just another example of scientists being very poorly served by science journalists.

Darwin Was Wrong?

Nevertheless, proclaiming that "Darwin was wrong" is a different story. That's an egregious example of journalistic hype and it's unacceptable in a magazine like New Scientist....The bottom line is that it's unfair to say that Darwin was wrong.

Graham Lawton: As I'm a senior editor too, however, I can't and won't claim that the coverline was entirely beyond my control. Not my ultimate decision, but I was in on the discussions. We knew we were courting controversy but the feeling was that the story was solid enough to allow us to be provocative and, in any case, the statement is true. So I feel very strong ownership of the article itself, particularly the print version (and I totally stand by the story, which is the product of weeks of hard work, extensive interviews with scientists, a stack of journal papers and much thought, despite what some bloggers are saying). I feel some ownership of the front cover "sell", though as always I'm acutely aware that it is 50% journalism, 50% sales pitch.

You have presented it as an argument for "knocking over" "the" tree of life, rather than elaborating it. This strikes me as a journalistic construct, "creating a conflict". Wording like "the battle over the tree", is pure journalism, of course, as are some other passages which read as hyperbole to me, e.g. "But today the project lies in tatters, torn to pieces by an onslaught of negative evidence." This isn't at all how it is perceived, at least to this scientist.

New Scientist says Darwin was wrong

Pity Roger Highfield, editor of New Scientist, which published an issue in which the cover was the large, bold declaration that "DARWIN WAS WRONG". He has been target by a number of big name scientists who have been hammering him in a small typhoon of outraged private correspondence (I've been part of it) that his cover was a misdirected and entirely inappropriate piece of sensationalism. We're already seeing that cover abused by creationists who see it as a tool — a reputable popular science journal has declared Darwin to be wrong, therefore, once again, science must be in retreat! — and I expect we're going to have to face the headache of many school board meetings where that cover is flaunted as evidence that students ought to be taught about how weak Darwinism is.

Darwin was wrong...ish

Notice that he allows for multiple speciation to occur in a single event? It's not hybridisation, but the topology is roughly the same. So does this undercut the very idea of a tree of life? I think it does not. In particular the really insanely stupid comment by Eric Bapteste of Pierre and Marie Curie University in Paris that "We have no evidence at all that the tree of life is a reality" is so far from the mark that it makes no sense unless you suppose in his mind the evolution of genes and the evolution of species are supposed to be identical. But the distinction between gene trees and taxonomic trees is as old as genetics, although the terminology is recent. So, all in all, either you have really bad journalism here...

Graham, I get corrected and criticised all the time for my blogging. Why don't you do what I do - suck it up and try to do better? Also note that I did not call you in particular really bad - in fact I was attacking the Telegraph article. Is reading for meaning difficult in science journalism?

Oh, and speaking of reading for meaning I will restate the point. Lateral genetic transfer is about gene trees. The tree of life is about taxa. Taxa do not equal genes. And for the groups of what we know now as the eukaryote branches of the tree of life - animals and plants, Darwin's overall point remains as solid as ever.

Why's Graham so Glum: Lawton Critiqued

In point of fact, Lawton himself states in the comments section of Sandwalk,

“I'm acutely aware that it is 50% journalism, 50% sales pitch”

So, why is Graham so glum? He’s clearly aware, as are most readers, that the cover is little more than a publicity stunt aimed at selling copy. He may be missing the very important point that although everyone recognizes the pitch, not everyone approves of the tactic.

Lawton, as well as the editorial staff of New Scientist, may think that sacrificing accuracy for the sake of profit is a respectable endeavor; however I would venture to guess that much of the magazine’s readership does not. In part, it may be that readership’s response to the cover that contributed to the comparatively apologetic tone of the article’s subsequent editorial (Editorial: Uprooting Darwin's tree tone).

At any rate, regardless of the profit margins involved in misrepresenting important biological contributions through creative cover making, why does Lawton continually assert that the article’s content somehow remedies the cover page?

I’ve read the article. It seems abundantly clear to me that Lawton’s goal was to firstly create an artificial dichotomy between Darwin’s branching tree concept and genetic studies involving horizontal gene transfer (HGT) and then, after accomplishing this, to pummel Darwin’s idea through literary biased language.

Was Darwin Wrong?

The primary, most general implication for the history of life is not changed. Darwin's tree of life posits common ancestry of all life. This is the central scientific fact that anti-evolutionists rebel most against. In fact, the new observations about biology continue to reinforce Darwin's history-changing insight that all life shares a common ancestry. There is no reason to provide anti-intellectual, anti-evolutionists with quotes like "The Darwinian paradigm is dead", because this complexity only enhances Darwin's most profound insight – the universal common ancestry of life.

There were many others. All were highly critical. I read most of them and was gratified to learn some new things about the project to revise the tree of life. Some of these insights are discussed below in this report.

Darwin's imagined Tree of Life is very similar to the modern eukaryotic tree above its base, and Darwin would have recognized it easily. Not so the eukaryotic base and the prokaryotic trees below it. New genetic information derived from DNA sequencing has revealed extensive horizontal gene transfer between different species, so the common representation of these "trees" is now a web, net, thicket, or bush, not a tree. Both the NS and Telegraph news articles allude to this when they are free of sensationalism. For example, both articles contain these statements from Dr. Ford Doolittle:

  1. ...downgrading the tree of life doesn't mean the theory of evolution is wrong - just that evolution is not as tidy as we would like to believe.
  2. We understand evolution pretty well it's just it is more complex than Darwin imagined. The tree isn't the only pattern.

These statements are non-objectionable and non-sensationalistic. However, these insights were achieved approximately a decade ago, so the 2009 British news articles are a little late in reporting this news. Dr. Ford Doolittle himself wrote the 2000 article I mentioned above. This article is scientifically accurate and not sensationalistic. In the article, Doolittle makes the following points:

One lesson is that the neat progression from archaea to eukaryote in the consensus tree is oversimplified or wrong.

Deep in the realm of the prokaryotes and perhaps at the base of the eukaryotic domain, designation of any trunk as the main one would be arbitrary.

At the top, treelike branching would continue to be apt for multicellular animals, plants and fungi.

His article contains an excellent illustration of the then-new and still current interpretation of the Tree of Life:


The revised Tree of Life illustrated in "Uprooting the Tree of Life"
by W. Ford Doolittle,
Scientific American, February 2000

Doolittle's illustration is still accurate today and reflects the new knowledge gained about the Tree of Life during the previous decade. It shows that the bacteria and archaea domains are heavily interconnected by HGT and the eukaryotes originated by HGT. More primitive, hypothetical cells also no doubt engaged in HGT. Above their base, the eukaryotes form trees just as Darwin imagined, since eukaryotic lineages and clades rely essentially on VGT.

Is it possible to write a detailed, scientifically-accurate, non-sensationalistic news story about evolutionary trees and the Tree of Life? Of course it is. An excellent one was just published in the New York Times. Written by Carl Zimmer, who specializes in essays, news articles, and blog columns about evolutionary science, this article presents the current scientific reality about researchers who are working to reveal the Tree of Life. To the many scientists Zimmer writes about, the Tree of Life is a very real object, not a construct that "lies in tatters, torn to pieces," or "is being politely buried," or is a "small irregular structure" as Graham Lawton would have us believe. Zimmer's article mentions Dr. David Hillis, one of the foremost molecular evolution researchers in the world and a professor of integrative biology at the University of Texas at Austin. As readers know, Dr. Hillis was one of the "experts" who reviewed the proposed Texas science standards at the request of several SBOE members. Hillis was highly critical of keeping in the "strengths and weaknesses" language so beloved by Creationists. Zimmer writes this about Dr. Hillis:

For Dr. Hillis, drawing the tree of life is not something to do simply because it’s there. He thinks it will become a practical tool, in the same way online databases of DNA have become practical tools for geneticists.

“What I’d really like is the entire tree of life on a small hand-held device,” Dr. Hillis said. Biologists would be able to put a tissue sample from a plant, animal or other organism in the machine, which would then scan its DNA and find its place in the tree of life, even if it’s a new species. The data could then be uploaded to a database, so that every biologist’s machine would get an updated tree. “It would be a ‘tricorder’-like device, able to identify any species on Earth in the field,” he said.

It is clear that Prof. David Hillis, Star Trek fan, believes that the Tree of Life has a future. Here is an extremely large and complete tree that Dr. Hillis had a hand in making:

 

This magnificent diagram is a cladogenetic tree of representatives of all living organisms. The fuzzy circumference of the circular diagram contains the scientific names of thousands of species representing all major taxa of the Eukaryota, Bacteria, and Archaea. I have magnified one tiny sector slightly to show the location of Homo sapiens. If I magnified it more, you could easily read the text. The best thing to do is download the original diagram in a 367 KB PDF file and explore it yourself. Notice that the most deeply-rooted species are archaeans, next bacteria, then protists, and so forth up to higher organisms.

In conclusion, the New Scientist article written by Graham Lawton was unnecessarily sensationalistic and contained both inaccuracies and misrepresentations. Some of these were his fault and some were the fault of the scientists he interviewed. The article tried to give a picture of the current state of scientific thinking about trees, but one that was ten years too late and was obviously timed to coincide with Darwin's 200th anniversary. The currently true picture of evolutionary trees is still amazing--with horizontal gene transfer among the roots, and better represented there as a web or network--but still similar enough to what Darwin imagined for most eukaryotic organisms that the grossly misleading "Darwin was wrong" cover was completely unscientific. Darwin could not be "wrong" about facts that were not discovered until over a hundred years after his death. A better cover, as many suggested, since National Geographic used it without scientific complaint, would be "What Darwin Didn't Know." But this perfectly competent title was just not sensational enough for New Scientist, whose cover suggested to millions of people, mostly Creationists--including some Texas State Board of Education members--that "Evolution was Wrong," since they still improperly refer to evolution as Darwinism. Also, the sensational cover and misleading article was deliberately intended to cash in on the celebration of Darwin's 200th anniversary. Instead, the cover was a party-pooper. This type of journalism is not just unsound and unscientific, it is shameful.

I will give the last word to four prominent evolutionary scientists and writers, Daniel Dennett, Jerry Coyne, Richard Dawkins, and PZ Myers. They wrote a letter to New Scientist published on 2009 February 18. The entirety of their letter deserves repeating:

What on earth were you thinking when you produced a garish cover proclaiming that "Darwin was wrong" (24 January)?

First, it's false, and second, it's inflammatory. And, as you surely know, many readers will interpret the cover not as being about Darwin, the historical figure, but about evolution.

Nothing in the article showed that the concept of the tree of life is unsound; only that it is more complicated than was realised before the advent of molecular genetics. It is still true that all of life arose from "a few forms or... one", as Darwin concluded in The Origin of Species. It is still true that it diversified by descent with modification via natural selection and other factors.

Of course there's a tree; it's just more of a banyan than an oak at its single-celled-organism base. The problem of horizontal gene-transfer in most non-bacterial species is not serious enough to obscure the branches we find by sequencing their DNA.

The accompanying editorial makes it clear that you knew perfectly well that your cover was handing the creationists a golden opportunity to mislead school boards, students and the general public about the status of evolutionary biology. Indeed, within hours of publication members of the Texas State Board of Education were citing the article as evidence that teachers needed to teach creationist-inspired "weaknesses of evolution", claiming: "Darwin's tree of life is wrong".

You have made a lot of extra, unpleasant work for the scientists whose work you should be explaining to the general public. We all now have to try to correct all the misapprehensions your cover has engendered.


Texas Citizens for Science
Last updated: 2009 February 24