dysnomia.us

darwin’s not wrong, he’s just old-school

I’m stepping away from my usual focus for a minute here, because those of us who support science should be aware of this story and how it could spin. It’s an awesome story that just makes science better, but I’m afraid New Scientist’s “Darwin was wrong” angle will be misunderstood or misused. It’s worth reading in its own right, but also so we can understand the changes in the field of evolution and speak effectively against the creationist zealots who will argue that scientists don’t really agree.

• Why Darwin was wrong about the tree of life

To summarize: Darwin’s model of evolution is often called the tree of life- a steady branching out of new species from earlier ones, all leading back to a theoretical single ancestor. Evolution occurs, according this model, in a forward direction along the branches of the tree.

DNA evidence, however, now strongly supports a model more like a web, in which genetic material is carried between branches in what they’re calling Horizontal Gene Transfer (HGT). Evolution occurs, according to this model, through genetic swaps and hybridization as much as through the forking of a single branch.

At first HGT was assumed to be a minor player, transferring only “optional extra” functions such as antibiotic resistance. Core biological functions such as DNA replication and protein synthesis were still thought to be passed on vertically. For a while, this allowed evolutionary biologists to accept HGT without jeopardising their precious tree of life; HGT was merely noise blurring its edges. We now know that view is wrong. “There’s promiscuous exchange of genetic information across diverse groups,” says Michael Rose, an evolutionary biologist at the University of California, Irvine.

It’s a radical and awesome idea that reshapes biology in the same way that quantum mechanics and relativity reshaped physics. It may well take just as long to penetrate the mainstream as modern physics has to overcome the Newtonian worldview, and could cause as much confusion for the layperson along the way.

But where there was no one actively attacking Newton, there is a large body of people trying to undermine Darwin. Not because they think his theory of evolution is old-fashioned or simplistic, but because they would prefer a more medieval view. As scientists thrash out a new model of life, the creationists will seize on their disputes as evidence that all this evolution business is “only a theory.”

So pay attention to this development, not only out of awe for nature and respect for science, but out of the need to defend scientific progress against reactionary fools. Know your science, and stand up for it.