Science Sometimes Disproves Common Knowledge . . .
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It's the job of a scientist to collect data and examine evidence. But what do you do when your dinosaur research leads to a discovery that isn’t possible according to conventional wisdom? Dr. Mary Higby Schweitzer, Biology faculty at NC State University in Raleigh, North Carolina, made this kind of discovery. But instead of giving up and leaving it a mystery, she set out to disprove our common knowledge.
All bone is protein plus mineral. The mineral makes it hard, the protein makes it flexible. If you remove all the minerals you have nothing, right? Except for, we removed the minerals and we had flexible, stretchy tissue. The more we dug into that, we began to see what looked like blood vessels. From there it’s just been, okay if we’ve got this stuff in more than one specimen what is it? What’s it made of? How does it compare with modern material? Has it been changed over time? Can we get any ideas of who these guys are related to at the molecular level, and how evolution progressed?
Doctor Schweitzer had stumbled on the impossible: soft tissue in dinosaur fossils, preserved for more than sixty five million years. Was this a fluke?
If you have a very neat phenomenon that you observe in science and it’s only a one-time thing, it really doesn’t have any value. So we did a survey. We started with modern chicken bone.
Birds are modern dinosaurs. Learn more about “The Dinosaurs in your Backyard” on a past episode of SciWorks Radio.
We found four components in the bone: blood vessels, collagen protein, bone cells, and blood cells. So we used those four markers, and we worked our way back in time. We did a thousand year old specimen, a ten million year old specimen, and the oldest specimen we looked a was a tiny-tiny fragment of triassic bone. We found three out of the four materials, at least, in about half of the specimens we looked at. We looked at about thirty five-ish specimens. They were different taxa, different continents, different depositional settings, different sizes, different everything, and so, it's not that uncommon.
So, not only is soft material in dinosaur fossils possible, but it's common. why?
When we look at some of the soft tissue materials, using different analytical techniques, there’s always an iron spike. So, we thought that makes sense, you know? I mean blood vessels contain red blood cells, and red blood cells contain hemoglobin, and hemoglobin contains iron. So maybe what we’re seeing is iron that when the red blood cells lysed upon death, got deposited on the vessel walls. And so, we took modern ostrich blood vessels that we took from bone, soaked them in hemoglobin, and they’re still sitting at room temperature in my lab four years later with no changes. The ones we didn’t treat with hemoglobin were completely gone in about three or four days. So we think iron plays a big role in initially stabilizing the material against degradation.
The iron hypothesis is currently the best explanation, but there are challenges. The most extreme come from some who see this as proof that dinosaurs lived not millions of years ago, but hundreds. So really, what evidence do we have to support dinosaurs as ancient animals?
If you look at all the evidence from astronomy, geology, sedimentology, biology, and evolution and molecular biology, it’s very consistent. The simplest explanation is we have a lot of evidence for an ancient Earth. In the most ancient rocks we don’t have vertebrates, and then they show up, and then they get more and more complex as you go up the sedimentary column in time. Where they are in the sediment column has been well dated. The overwhelming evidence is that these guys were very old, but not as old as some fossils that we have. What we are supposed to do as scientists is question everything, and never, never ever accept something because someone said so, or because everybody knows. Show me the data. That’s what I want to see, and if your data says what you claim it to say, I’m good with that until some more data comes along. That’s what science is all about. You cannot prove somebody right, however, that’s not the job of science. Science is to disprove. And if you can’t disprove something, then it's supported. But it’s not proven. That’s not our job.