Can Ancient Fossils Prepare Humans for the Future?
Warming under the Cretaceous sunlight, a dinosaur forages near the mouth of a river. Without warning, she is knocked into an underwater pool by a flash flood. Buried by the load of mud and rocks carried in the water, she dies.
Without oxygen or scavengers, she remains intact. Her bones are replaced, molecule by molecule, by minerals and become rock. Ninety million years after her death, the surface erodes away, exposing her to the sunlight once again.
Recently, Drs. Lindsay Zanno and Victoria Arbour, from the North Carolina Museum of Natural Sciences (check out their Paleontology Lab), took a brief scouting expedition to New Mexico, looking for fossils exposed at the surface of 90-million-year-old rock. Only three North American dinosaur species have been identified from this time period. They want to find more.
Zanno: The process of finding dinosaurs is largely, you get out, you walk around and you cover the hills, and you visually look for fossils that are eroding out of the ground. So our team, which is about five to seven people, would simply just hike up and down these badland hills for eight to ten hours looking for little bits of fossil. So we did that for about a week before we found any bone at all.
Arbour: We found some dinosaur fossils, so that was great, and we found some things that probably represent a new species. But it will take a lot of time to figure out whether or not it gets a new name or what kind of dinosaur it really is, but that was exciting. And when you only have three from a given area, there’s a good chance that if you find something it’s going to be something new.
To fossilize, an animal must be buried shortly after death. Sometimes the bones have been scattered first by scavengers or other natural forces, but sometimes, the animal is buried all at once, remaining undisturbed for millions of years.
Zanno: We found about 42 vertebrae, which are the bones of the spine, just laying on one hillside, which is really rare. Usually you find a couple of pieces of one bone, but you don’t find most of the skeleton just laying on the surface.
Bones aren’t the only things that fossilize. Sometimes a paleontologist will uncover evidence of ancient ecosystems.
Arbour: We also found footprints from dinosaurs, some sort of swimming fish or crocodile; something weird that we couldn’t figure out right there, but some kind of undulating traces.
Zanno: We found lots of fossilized plant material, the remains of some turtles, looks like a couple different types. We found remains of crocodiles; we found some fish scales, and then we found some different types of dinosaurs, and so we’re trying to lay all this out and figure out the different components of the ecosystem that we came across.
The principle of Uniformitarianism states that the natural forces at work now are the same as in the past, and will remain the same in the future. That is why dinosaur discovery and exposing ancient ecosystems is important to us.
Arbour: If you just look outside and see the amount of species loss that’s happening just through human-related climate change right now, that’s happening a lot faster than what we’re seeing in the fossil record.
Zanno: And what we’ve learned is that a lot of these North American dinosaurs disappear. Even though climate change, during the time we’re talking about, is happening much more slowly than anything we’re experiencing now. If you change the habitat, sometimes animals just aren’t responding to that.
The ecosystems that you live in now didn’t evolve in a vacuum - every interaction, every dependency species have on one another. And, if you don’t think that humans are dependent on the rest of the species of this planet, then you might as well stop taking medicine, stop eating food, right? We are a part of an ecosystem, and we need other species for our survival. Those relationships are a product of four billion years of evolutionary history, and, to really understand what those relationships mean, we need to go back to the fossil record because that is the only real data we have on how ecosystems have changed in response to a changing planet.
Other SciWorks Radio interviews from these guests: