08 September 2005

Communications and Science,

A little more than a week ago, Mike Syvanen posted an article on Panda's Thumb that discussed a real controversy within the field of evolutionary biology: the role of horizontal gene transfer in early evolution. Today, Paul Nelson misinterpreted that article in a post over on ID: The Future. The specifics of this incident have been covered in more detail both by at Evolving Thoughts, and at Evolutionblog. I'm going to look at this incident from a slightly different perspective: how it illustrates some of the communications issues that scientists are forced to face when dealing with creationists.

I read Mike Syvannen's article, and found it both enjoyable and thought-provoking. I certainly found it to be quite understandable. That is to be expected, of course. I am a grad student in zoology. I read scientific papers on a daily basis and I am familiar with the terms and concepts that appear in scientific papers. I suspect that reading Mike's article would be a very different experience for someone who did not have a strong foundation in biology. Such a person would have been confronted with unfamiliar terms and concepts - lots of them, tightly packed, and with very little familiar ground in between.

That is not meant in any way as a criticism of the paper. The concept of horizontal gene transfer is complex. Understanding how horizontal gene transfer might affect evolution is even more complex. Learning how to read an unrooted phylogenetic tree is complex. Understanding what a phylogenetic tree is is complex. Understanding the mathematics involved in finding the best phylogenetic tree for a set of data is extremely complex. Evolution is a complex science, and complex things can be very difficult to explain in simple terms.

Intelligent design has been accused of being a number of things. Complex isn't one of them. Anyone can follow the basic ID argument: Evolution can't explain it, so God must be the explanation. Some of the IDers might try to wrap that up in some more complex-looking outfit, but the basic argument remains unchanged. In fact, they can't really change it much, since the sheer simplicity is a large part of their argument's appeal.

That's a difficult enough situation, but unfortunately it's just the beginning. Many of the IDers are not above taking advantage of the complexities of real science. It is very easy to misrepresent a complex concept, and it can be very difficult to correct the misrepresentation. This is exactly what is happening with Nelson's misrepresentation of Mike Syvannen's article.

Nelson wrote:
Turns out Mike Syvanen is explaining why Darwin's tree of life -- Mooney and Nisbet's orthodox "common ancestry of all organisms on earth" -- may not be the case, because life may have arisen from multiple independent starting points.


That's a single, long sentence containing 37 words. I'm now going to try to explain, in as simple terms as I possibly can, why this misrepresents what Syvanen was actually arguing.

The conventional way that people have thought about evolutionary descent is as a tree, with all living things branching off from a single starting point - like the family trees that show all of the descendents of one couple. The reason that people have thought about evolution as having happened this way is because parent-to-child was the only way that anyone knew of for genes to be passed on. Over the last thirty to forty years, we have discovered that there are actually some other ways for genes to be passed on to someone else. It's been found that bacteria can transmit small pieces of DNA to other bacteria, that they can do this even between bacteria that are not part of the same species, and that the DNA can contain usable genes. People have seen this happen, and it looks like this kind of gene transmission has helped some kinds of bacteria to get resistance to antibiotics. It also looks like there are some species of virus that can move chunks of DNA from one species to another.

These kinds of non-traditional genetics seem to be more important in things like bacteria than they are in big, multicellular organisms. But way, way back in time everything that was alive was something like bacteria. If that kind of "sideways" movement of genes was important then, we might need to change the way we think about the evolution that was happening then. When we thought that traditional, parent to child genetics was all that went on, we could draw the lines of descent as all running straight from parents to children. But we can't draw those kind of lines if the "child" is also getting some genes from a somewhere else. Instead, we have to draw at least two lines leading to that child - one from the "parent", and one from any other bacteria that contributed genes. If we do that, we don't have a drawing that looks like a tree. We have a drawing that looks like a net.

What Mike Syvanen suggested is that life could have started several times in that "net" of parents, instead of just once. If he is right, then what it would mean is that not everything alive today is descended from a single species. Instead, it would mean that everything that is alive today is descended from a pool of species that were able to (and did) swap some genes back and forth. It doesn't mean that things alive today don't have common ancestry. It just means that the ancestry worked a little different, and a little bit messier, than we used to think about it.

That took 444 words, arranged in seventeen sentences over three paragraphs. It took about half an hour to write. It wasn't as clear as I hoped it would be, and there's a good chance that it would bore the hell out of anyone who isn't really interested in evolution (and maybe some who are). Paul Nelson's comment, on the other hand, was a complete misrepresentation of what was actually written, but it was short, clear, and to the point.

This is a problem. Evolution, like most of the natural world, is very complex. It is simply not possible to explain why Nelson was lying about what Syvannen said in anywhere near the number of words that it took him to do it. I suspect that Nelson and other ID proponents know this, and that is why they do it. I wish I could say that I know how we can counter that strategy, but I do not. A short and simple lie can sound a lot more compelling than a messy and complicated truth. That's just a fact, and it's something that we're going to have to continue to work around.

8 Comments:

Blogger Ed Darrell said...

There are lots of short things to say that are at least crudely accurate, and which lay out facts that can be presented in a more understandable way.

Such as:

"Understanding evolution gives us better crops."

"Evolution says you look a lot like your father because traits are heritable. This is a foundation of civilization, that genes, and also property and history pass father to son, mother to daughter, parents to child."

"Evolution tells us that animal research can accurately predict how drugs will work in humans; it also warns us about the ethical issues of experimenting on life we are really related to."

"Evolution tells us we really are a brotherhood of man, a tighter family than most other species."

"You can't understand the controversy if you don't have the facts, first."

"Studying evolution produces cures for cancer."

"Evolution says you're descended from your mother. Intelligent design says, 'Maybe not.'"

Heck, I'm sure there are better, shorter things to say, too.

I am amused myself by the thrust of ID argumentation that claims, first, ID is scientific because it accepts Darwinian explanations everywhere there's not a rational ID explanation, but second, Darwinian science is in error in it's search for rational explanations of proximate causes. Go figure.

1:41 PM  
Anonymous Anonymous said...

Unfortunately, the reporters and newscasters want short, pithy remarks--they prefer 37 words to 444 words, regardless of whether suitable information is conveyed. The ID folks know this, and are aware of the horsehockey:set-the-record-straight word ratio. Maybe it would help to come out first with the short phrases (like the ones ed suggests)rather than waiting to be on the defensive.

3:40 PM  
Anonymous Anonymous said...

"The 'tree of life' is a good approximation, but with the gene-swapping activities of bacteria and viruses, the actual tree has small web-like connections between branches. Near the trunk where all life was microscopic, these connections dominate among loosely-defined species in a community which freely exchanged genes." - Timothy Chase (47 words)

5:12 PM  
Anonymous Anonymous said...

Honestly, I think I like TQA's explanation better.

-Timothy Chase

5:19 PM  
Blogger Hari Narayan Singh said...

I don't understand why lateral transfer precludes a single common ancestor. If the first species all used RNA, wouldn't they have to have a common ancestor before they diversified and then started exchanging information?

5:45 PM  
Blogger TQA said...

Lateral transfer does not preclude a single common ancestor, but it does mean that a single common ancestor is no longer necessary. Mike Syvanen's point, at least as I understood it, is that it is more parsimoneous to discard the (unnecessary) single ancestor.

Personally, I'd reserve judgement about how parsimoneous one ancestor is versus many until we know a good bit more about the origin of life.

7:08 PM  
Blogger Salvador T. Cordova said...

Mike or anyone,

I have heard some anti-IDists comment on the article in question. Several say that it implies abiogenesis may have happened several times independently. Do you share that interpretation?

I'm reluctant to make that interpretation because I don't see explicitly written down, but that seems to be one of the possible conclusions.

Thanks.

Salvador Cordova

2:46 PM  
Blogger TQA said...

I think it depends on what you mean by "implies". The way I read the article, if horizontal gene transfer was as major a mechanism in evolution as some believe, than multiple abiogenic events is possible. However, it does not imply that multiple abiogenic events are necessary. Does that help?

As I read the article, Mike Syvanen feels that an evolutionary scenario where there is widespread lateral transfer makes multiple abiogenesis a more parsimoneous explanation than a single event. My own personal feeling is that right now we don't know enough about the origin of life to say which explanation would be more likely.

3:25 PM  

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