You can’t go for a month without seeing a claim that some new discovery has rewritten evolutionary history. If headlines are to be believed, phylogeny – the business of drawing family trees between different species – is an etch-a-sketch science. No sooner are family trees drawn before they’re rearranged. It’s easy to rile against these seemingly sensationalist claims, but James Tarver from the University of Bristol has found that the reality is more complex.

Check out the full post.

I appreciate comments and ideas from everyone, but I am especially interested in hearing from science writers as they are the intended users.

1. Misconceptions about evolution.

Check. Here’s a headline from a press release by Rice University: “Sponge shines light on life’s origin”. This is off by about 3 billion years. The subtitle to the press release is also awful: “Genome connects the dots between Amphimedon, animal descendants”. Nope. Amphimedon queenslandica is a modern species and is not the ancestor of any non-sponge animals (and probably not of any sponge species either). The common ancestor of all animals may have been sponge-like, but it was not a modern sponge species.

2. Hype about medical significance.

Check. The original paper itself and various news stories play up the “sponges will teach us lots about how to cure cancer” angle. I’ll be glad when (if?) it becomes unnecessary to tie everything to human health for it to gain support. Sequencing the sponge genome has many merits on its own, but the realities of grant competitions dictate that one must often find a link to cancer or climate change to get funded.

Anyway, kudos to the researchers on an interesting contribution to the animal genome dataset!

UPDATE: Along with Jonathan Eisen, I am glad to endorse the press release by UCSB, which shows how important evolutionary concepts can be weaved effectively into a news report. I *almost* was put off by the use of the term “basal”, which is terribly misleading and some implication that this *species* has been around for 650 million years (it definitely has not), but the story author and the researchers interviewed totally redeem themselves with this: “‘You had some ancestral animal that is long-since extinct, and its descendants became these modern-day sponges that we have, and there were other descendants that became the rest of the animal kingdom –– from jellyfish to baboons,’ said Kosik. ‘We speak of the sponge as being this earliest branching phylum, or group of animals.’ ” I’m not sure who the author of the press release was, but he/she did a very nice job here.

One thing that troubles me, however, is that amidst all the good advice being provided to aspiring writers, almost no one has said anything about actually talking to scientists or how to go about doing so. Not much about fact checking, or confirming that the quotes are correct. Lots of “you don’t need to have any training in science” though. Several of the writers have, for no obvious reason, taken digs at scientists. This bothers me.

Scientists love science, too. We like to have our work understood and appreciated. We enjoy having our research discussed outside of scientific journals. However, for the most part we are very anxious about being misquoted or having our research over-hyped. A misconstrued quote can do a lot of damage to our credibility among peers.

I freely admit that many scientists are skeptical, even dismissive, of science writers. Some think that science writers are people who wanted to be scientists but couldn’t hack it (something like this comes up in a number of the writers’ posts, actually), or that they have no experience in science (also common in the posts) and therefore don’t understand what research is like and how important accuracy and tentative conclusions are. Lots of scientists have been burned by stories that caused them embarrassment for much longer than the short lifespan of a typical science story. I have no patience for science writers who don’t respect the practitioners or values of science. (Nor for scientists who oversell their results or make basic errors of interpretation).

All of this said, I recognize that good science writers care a great deal about accuracy and appreciate the challenges of doing science. Likewise, good scientists make an effort to communicate their work both to colleagues and to a larger audience. In this sense, the good writers and good scientists are on the same team and have very complementary skills.

As a follow up discussion, I think it would be useful to consider two additional questions:

1) What advice do scientists have for science writers to ensure accuracy of their stories?

2) What advice do science writers have for scientists to improve their communication with writers and the public?

I have some ideas for #1 but I’ll wait to hear from readers, and I certainly look forward to some feedback for #2 (there are also books on this topic, which scientists should consult).

We need good science writers. (We also need scientists who write well about science, but that’s a different topic). As scientists, we need to point out the best among them and to be willing to help them communicate research in an accurate and interesting way. A good science writer, incidentally, is one who does not consider accuracy versus interest an either-or choice.

Anyway, I am sure that there are some aspiring science writers who read this blog, and others who have not yet recognized it as a viable career path for which they may be well suited. Fortunately, one of the best — Ed Yong of Not Exactly Rocket Science — has begun compiling the stories of science writers and their routes into the profession (On the Origin of Science Writers). If you have an interest in scientific communication then this is highly recommended reading.

Segmentation Is the Secret Behind the Extraordinary Diversification of Animals

ScienceDaily (July 27, 2010) — Segmentation, the repetition of identical anatomical units, seems to be the secret behind the diversity and longevity of the largest and most common animal groups on Earth. Researchers from CNRS and Université Paris Diderot have shown that this characteristic was inherited from a common segmented ancestor thought to have lived 600 million years ago and whose presence “changed the face of the world.”

…

[Arthropods, vertebrates, and annelids] are not closely related to one another. So, where does their segmentation come from? Is it possible that they all inherited this feature from a very distant common ancestor that lived 600 million years ago, before the Cambrian explosion, which produced most of the large animal groups that exist today? Or has segmentation occurred several times during the history of evolution? This is the question addressed by the researchers of CNRS and Université Paris Diderot at the Institut Jacques Monod, because segments seem to offer a significant advantage to the groups that have them, in terms of diversity, longevity and overall evolutionary success.

…

The researchers found that the genes controlling segment formation during embryo development are almost the same in drosophila (an arthropod) and in annelid marine worms, on which they concentrated their studies. These similarities led them to conclude that the genes had been inherited from a common ancestor, which was itself segmented. It also appears that vertebrates inherited this characteristic from an ancestor they share with the arthopods and the annelids. This is what the researchers are now seeking to confirm.

Arthropods are segmented and very diverse. Nothing newsworthy there. But wait, what’s that? The second largest phylum is molluscs, which aren’t segmented? And what else? Nematodes, which are undoubtedly hyperdiverse, aren’t segmented either? Early-branching animals like sponges, cnidarians, and ctenophores aren’t segmented either, you say? Only three phyla are segmented, two of which (Chordata and Annelida) are not as large as Mollusca and Nematoda? Hmmm.

Anyway, the story (which is bad, even by press release standards) suggests that finding a common gene involved in segmentation in three distantly related phyla implies that their common ancestor had the gene and therefore was segmented as well. We’ve been through this whole “shared regulatory gene equals homology of morphological trait” issue with the eye. The alternative interpretation is that the same genes were co-opted for similar functions independently. The authors of the original paper dismiss this possibility in one sentence:

“Because they are not known to be part of a conserved core regulatory network or “kernel” that might have been coopted en bloc, each gene would have been recruited independently, which seems unlikely.”

Let’s think about this for a minute. Yes, it seems “unlikely” that the same genes would be co-opted three times for similar functions. But the hypothesis that the ancestor was segmented requires another major assumption.

Here is a very basic phylogeny from an introductory textbook.

For the ancestor of chordates, annelids, and arthropods to have been segmented, this means that segmentation must have been lost in molluscs, nematodes, echinoderms, brachiopods, rotifers, flatworms, and various smaller phyla. Moreover, several of these phyla that lost segmentation subsequently became more diverse than chordates and annelids.

Another example of misunderstanding phylogenetics.

Anyway, New Scientist seems to have fallen for this in their interpretation of a recent paper.

Bellyflopping frogs shed light on evolution

Playing leapfrog would be tricky for the most primitive living frogs: those from the Leiopelmatidae family crash-land rather than touch down gracefully after leaping. The finding may reveal how frog jumping evolved.

Richard Essner of Southern Illinois University in Edwardsville suspected unusual jumping behaviours in leiopelmatids because they are known to swim differently from other frogs, using a “trotting” movement rather than a synchronous double kick.

Essner’s team used high-speed video to compare jumping in three leiopelmatid species with two more-evolved species. Whereas the more advanced species begin to fold up their hind-limbs in mid-air to prepare for landing and their next leap, “Leiopelmatid frogs don’t fold up their legs until after they’ve hit the ground,” he says.

Ascaphus montanus, the most primitive species, kept its legs splayed as it landed in a belly flop or nosedive, then skidded to a halt on its belly. Perhaps it’s no surprise that frogs evolved to jump before they could master landing.

The authors of the paper state several times that these frogs retain the ancestral swimming style. Presumably this is backed up with clear evidence in the fossil record, and not just position on the reconstructed phylogeny. Otherwise, there is an obvious alternative interpretation: the swimming mode in leiopelmatids is derived and results in a reduced leaping ability. Given that they are mostly aquatic and have other derived adaptations to life in fast-running streams, this is not at all implausible. Again, these are all modern species that have been evolving for exactly the same amount of time since their split from a common ancestor.

UPDATE: Evolutionary concepts are often superficially simple but in fact very difficult to grasp correctly. This story shows how this extends to both researchers and science writers and, presumably, their readers. New Scientist, Scientific American, Discoblog (Discover), Ed Yong (Discover), the journal (Naturwissenschaften), and the study authors all appear to be confused to some extent about what “primitive” means and how one establishes ancestral vs. derived characteristics.

Here’s an example from my paper on evolutionary trees. Which is more “primitive”, “early branching”, “least evolved”, or what have you? Can you conclude anything about the ancestor of echinoderms and chordates by comparing modern humans vs. modern echinoderms and assuming the early branching lineage is primitive?

I have tried to tackle these in my previous series of reviews in the journal Evolution: Education and Outreach. Sadly, despite some moves in the right direction, these are still not freely available from Springer.  (You may recall that I resigned as associate editor over the lack of access).

However, if you want to send a PDF to someone who is confused about these topics, you can get the papers at the links below.

Gregory, T.R. (2009).  Understanding natural selection: essential concepts and common misconceptions.  Evolution: Education and Outreach 2: 156-175.

Gregory, T.R. (2008). The evolution of complex organs.  Evolution: Education and Outreach 1: 358-389.

Gregory, T.R. (2008). Understanding evolutionary trees.  Evolution: Education and Outreach 1: 121-137.

Gregory, T.R. (2008).  Evolution as fact, theory, and path.  Evolution: Education and Outreach 1: 46-52.