Margaret is on the hunt for fossils with scientists from the Cleveland Museum of Natural History. We learn what fossils can teach us about the past and how to compare them with modern creatures.
Class Discussion Questions:
1) Research the dunkleosteus. What modern animal is it most similar with. Support your answer.
2) Why are fossils important to scientists? What can they teach us about the past, and present?
3) What factors impact how well a fossil is preserved?
Read the Script:
[Margaret] I'm excited about this one. We're headed on a hunt for fossils in a special Northeast Ohio spot with scientists from the Cleveland Museum of Natural History. Science is all about making discoveries and learning how the world works. Fossils let us understand what the Earth used to be like and how it's changed.
- So a fossil is any evidence of past life, so it could be an animal, it could be a plant, it could be some trace that the animals leave behind, like a track way or even fossilized poop. I am Dr. Caitlin Colleary and I am the assistant curator of vertebrate paleontology at the Cleveland Museum of Natural History.
[Margaret] That's a long job title, which essentially means Caitlin studies ancient animals that had bones. Over time, the Earth has changed, and so have the animals. The fossils we're looking for today can help teach us what the world was like long ago.
- So behind me is actually the Cleveland Shale. So this is a really cool area for fossils. And it's from the Devonian Period, which was about 358 million years ago. And it was the ocean. And so, we were actually a lot closer to the equator back then, too. So it was like a tropical ocean. And it's full of really big, weird fish. Dunkleosteus is probably the best known. One of the cool things about them is that we only really find their heads because they had bony plates in their heads, but their bodies were cartilaginous like sharks. So we usually don't find their bodies preserved, but we find a lot of heads. And we actually learn a lot about them by studying their jaws. That's something that's really commonly preserved, and we can figure out the sort of things that they were eating and what kind of behaviors they were doing. What kind of animals they were, basically.
[Margaret] The dunk's pretty different from today's sharks. For example, instead of having teeth, it had long, sharp plates on its jaws, almost like a beak. Its features weren't passed onto modern guys because it went extinct with many of the other big, weird fish. Scientists are still looking for clues about what changed in the environment to cause their demise, thus fossil hunting. Okay, big bony-headed fish. That sounds like it would be easy to spot, right? And surely these scientists have some fancy equipment, too.
- There's really not any sort of advanced technology in terms of finding fossils still. So we kinda just walk around looking for them. We know where to look because we know the age of the rocks and the things that we're looking for, what types of rocks that they're in. And so, we go and walk around and look at those rocks.
[Margaret] What's it like to actually find a fossil?
[Caitlin] You get really excited first, especially if you're in the Cleveland Shale, because you do not find fossils very often, and you excavate it, if you can. Take it back to the museum. The museum, maybe 10% of the fossils that we have at the museum are actually on display. Most of them are down in the basement where researchers work on them. And we have a lab down there where we clean up the bones and put them back together and try to figure out what those animals were like.
- I might need to clean off my glasses better because we didn't find any fossils on our trip. But like Caitlin said, often it's when you least expect it that they appear.
- So my favorite fossil that I ever found was when I was in Panama working along the Panama Canal. When they dug the Panama Canal, they exposed all of these rocks. And so we were working on the Panama Canal. And I was sitting, looking at the outcrop all day and it was hours and hours of finding nothing. And at the end of the day, I moved back and started dusting off the spot where I was sitting and I saw a tooth, and then I saw another tooth, and I saw another tooth and I realized that I'd been sitting on this tiny horse jaw all day. And it was this little tiny horse, about the size of a labrador. And we got to excavate the jaw and it was really cool.
[Margaret] If you happen to find yourself sitting on a tiny horse fossil, Caitlin says, snap a photo and take a note of its location, but don't try to excavate it yourself. Instead, contact your nearest museum and have the experts there come take a look.
- So fossils are basically the only way we really get to know about what life was like on the planet throughout all of Earth's history. We have to be careful with fossils, and we also have to make sure that they end up in the hands of scientists. Otherwise there's so much information that we'll never actually get to learn.