Darwin Was Wrong?

The cover is this week's issue of New Scientist is sure to get your attention.

I happen to believe that the science of evolutionary biology has moved on since 1859, and I happen to be a proponent of evolutionary processes that Darwin new nothing about. 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 main article is Why Darwin was wrong about the tree of life. The author is science journalist Graham Lawton.

The essence of the story is that the early history of evolution is probably characterized by a net of life and not a traditional tree. The "net" metaphor is due to many example of lateral gene transfer.

Ever since Darwin the tree has been the unifying principle for understanding the history of life on Earth. At its base is LUCA, the Last Universal Common Ancestor of all living things, and out of LUCA grows a trunk, which splits again and again to create a vast, bifurcating tree. Each branch represents a single species; branching points are where one species becomes two. Most branches eventually come to a dead end as species go extinct, but some reach right to the top - these are living species. The tree is thus a record of how every species that ever lived is related to all others right back to the origin of life.

For much of the past 150 years, biology has largely concerned itself with filling in the details of the tree. "For a long time the holy grail was to build a tree of life," says Eric Bapteste, an evolutionary biologist at the Pierre and Marie Curie University in Paris, France. A few years ago it looked as though the grail was within reach. But today the project lies in tatters, torn to pieces by an onslaught of negative evidence. Many biologists now argue that the tree concept is obsolete and needs to be discarded. "We have no evidence at all that the tree of life is a reality," says Bapteste. That bombshell has even persuaded some that our fundamental view of biology needs to change.

As it happens, I was at a function last night with Jan Sapp of York University (Toronto, Canada). Loyal Sandwalk readers might recall a series of articles on the Three Domain Hypothesis. The articles were based on a book edited by Jan Sapp. Sapp is a supporter, as am I, of the scheme advocated by Ford Doolittle (see below).


This net, or web, of life is characteristic of the earliest stages of evolution when all organisms were single cells and the distinction between eukaryotes and prokaryotes was barely discernible. Once the main groups rose out of the web, they evolved pretty much as you light expect by binary speciation events. This gives rise to a traditional tree-like pattern.

As Jan and I discussed, for the last three billion years of evolution the tree of life is a very good metaphor for evolution. Darwin was mostly right about that. On the other hand, the New Scientist article discusses some problems with the tree of life that extend beyond the early history. It makes several valid points that should make everyone skeptical of claims about evolution that are too simple. The tree isn't perfect.

The bottom line is that it's unfair to say that Darwin was wrong. It's as unfair as saying the Newton was wrong because of Einstein. We need to recognize that modern evolutionary biology is an improvement over the view of the Victorian founder of the field, but a cover saying that Darwin was wrong conveys the wrong message. It suggests that up until recently scientists believed that Darwin was right about everything.

A better headline might be: "More evidence that Charles Darwin didn't know everything there is to be known about evolution when he published his book in 1859."

UPDATE: In a surprising development, the IDiots at Uncommon Descent have picked up on these recent (sic) developments in evolutionary theory. Paul Nelson, a Young Earth Creationist philosopher, writes: “The tree of life is being politely buried”.

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