I’ve said it before and I’ll say it again: I love a scientific controversy. A good, well reasoned, no holds barred assessment and presentation of the evidence where the ultimate goal is truth, a truth that frequently turns out to be far more nuanced then first thought. One thing I really don’t like is the lazy, distorted, oversimplified way that such controversies are portrayed in the mass media. Generally the science specific outlets will do a better job, although even they can slip up from time to time; but the mainstream press almost universally gets it wrong.
The particular story that I have a bee in my bonnet about this week has to do with the demise of the dinosaurs. A couple of weeks ago there was a paper published, in the Proceedings of the National Academy of Sciences, that argued that nearly all types of dinosaur were in decline for several millions of years before the asteroid impact at Chicxulub that most scientists agree was the cause of the mass extinction event 66 millions years ago. Now, there’s nothing wrong with this assertion, it appears to be a thorough and well researched paper that adds an interesting, additional layer of understanding to a difficult problem. Unfortunately this level of sophistication is apparently too much for the average journalist to try and convey and so what most of them decided to do was to claim that the asteroid impact was of no consequence and that the dinosaurs were all nearly dead anyway. In scientific circles this is what’s known as bullshit.
In their study the authors conducted a very thorough analysis of the three types of dinosaurs extant at the time; the theropoda (these are your velociraptors and T-Rex), the sauropodomorpha (think brontosaurus and diplodocus) and the ornithischia (stegosaurus and the like). They looked back more than 200 million years into each of the these three clades to see how many new species were evolving (speciation) compared to how many were becoming extinct. They found that all three had more species becoming extinct than being created for at least 40 million years before the end of the cretaceous period.
So what does that mean? Well, the authors argue that if a clade is having more extinction events than speciation events that this means there is less diversity (this is definitely true) and therefore less chance that the clade would be able to survive a massive trauma like the asteroid impact (this is just a hypothesis, though a reasonable one). They note that there were exceptions to the lack of speciation; the hadrosauriformes (duckbilled dinosaurs like iguanadon) and ceratopsidae (think triceratops) sub-clades were doing just fine. These two groups made up about 14% of known dinosaur species at the time and were rapidly speciating right up till 66mya.
That is the extent of their claims. They do not claim that all the dinosaurs were gone before Chicxulub, nor that had the impact never occurred that dinosaurs would have died out anyway. Any assertions further than that in the reporting of the paper were completely fabricated in the mind of the journalist. The inanity of the reporting was brought into stark relief when, only three days later, a second paper was published in Current Biology that, on the face of it, seemed to contradict the first. I don’t know whether it was a) a herculean effort of compartmentalisation or b) a complete absence of caring that then allowed some journalists to write a story that contravened their one from three days earlier, but either way it’s a bad thing.
This study looked at a much smaller group of dinosaurs, the maniraptora. These are small, bipedal critters with long arms so think of tiny T-Rex but with less comic potential. Most species would have had some kind of primitive feathering, especially when young, and it should be noted that modern birds all descended from this group. They looked at thousands of maniraptora teeth to see if they were changing in the lead up to the mass extinction of 66mya, the idea being that this is another way of looking at the speciation:extinction ration. If the morphological diversity decreased then it may be assumed that there were fewer species present and the maniraptora were in decline.
They found, however, that they were doing perfectly well; there was no indication at all that they were dying out in the lead up to the asteroid impact. They also noted that all toothed maniraptora very suddenly died out 66mya whilst the non-toothed ones survived; it is this group of species that went on to become modern birds and is also the explanation for why not one bird species today has teeth. Their hypothesis is that toothless birds were able to survive by eating seeds; one of the few foodstuffs that would have survived the nuclear winter long enough to sustain populations until the recovery began which, I think, is fascinating.
Instead of picking up on the interesting hypothesis as to why non-avian dinosaurs died out whilst the ancestral bird ones went on to flourish, many writers simply contradicted themselves and claimed all dinosaurs were fine and only the asteroid impact was of significance. It’s no wonder that the general public often accuse scientists of constantly changing their minds.
Perhaps most depressingly of all is the fact that this isn’t a problem unique to science reporting. Politics, business news and every other type of reporting is suffering from the same disease. The misguided notion that every concept, no matter how complex, must be crowbarred into on of two binary positions leaving no room for nuance or finesse. It’s us or them; it’s yes or no; it’s love or hate. Mercifully there remains a few decent outlets that are still willing to spend an hour or two properly understanding a story rather than instantaneously trying to generate clickbait, but finding these can be difficult, especially for readers that aren’t used to having to deploy their own critical thinking skills. I would like to think that most people would know not to get their science news (or any news, frankly) from tabloids, but despite dire predictions of the future for the dead tree press they still hold significant sway with the masses. I dread to think what Daily Mail readers think causes cancer.