[MUSIC] I'm Bruce Fouke from the University of Illinois, Urbana-Champaign. If we think about the idea of crimes and our ability to reconstruct a crime scene, we immediately think of crimes that might have happened days, or hours, or weeks ago. And we think immediately of crime scene investigation units that are housed in police departments all over planet Earth. And this ability to use a combination of observation and very clever intuition. And also apply the most cutting edge tools that we have available, both in terms of the physical analysis of objects, the photography of objects, or the DNA and RNA extraction from blood, and bones, and other body parts that are found at crime scenes. This is something that almost everyone now is quite familiar with because of the popularity of TV shows. But one way to look at evolutionary biologists who study evolutionary history and the history life itself through geological time, it's required that those scientists are truly forensic scientists who do a very similar type of work as CSI, except the time-frames are different. We're talking about going back and finding the beheaded carcass of a hadrosaur that went crossways with a tyrannosaurus rex during the cretaceous time period about 110 million years before present. But fundamentally, the approach is the same. [COUGH] So, I think it's really important to evaluate what are the lines of evidence because eventually we have to stand in a court of law. Now, of course, it doesn't have to do with modern-day crimes but the court of law for an evolutionary scientist is the ability to publish. And then from those publications, they'd be able to write grants and gain new research funding to do the next line of investigation. So there is a court of justice when it comes to doing science, and it's very, very intense, [COUGH], and it's very competitive to do this. So what are those lines of evidence for doing dinosaur crime scene investigation? Well, one of them is that dinosaurs, part of the diapsid reptile lineage, they had very thick and leathery skin. So the skin itself is very preservable. Or it can become fossilized relatively easily. And that's really the question for us is, what are the pieces and parts of the history of the body or the life of a dinosaur that could actually get fossilized. So preservation potential is what we want to think about. So in this picture you see, is a good example of a large piece of dinosaur skin. That was beautifully preserved from the cretaceous time period, and this one was found in some of the classic fossil sites that are up in Canada in Alberta. And in this piece of dinosaur skin that was fossilized we have beautiful preservation of the individual cells. There are many plants that undergo these kind of preservations things. Like the petrified forest where you have groundwater move in, and at an ion by ion basis dissolve out and remove the original plant cells and then precipitate a mineral-like silicon dioxide in its place. So we call that replacement fossilization. Well, the same thing happens with dinosaurs, but even more remarkably we have examples of the replacement of dinosaur skin into another type of mineral. But even other deposits, we've been finding that the dinosaur skin itself is still partially mummified and preserved. So, we have a lot of information about dinosaur skin from these slabs and pieces of dinosaur skin that have been found in the geological record. One thing that we don't have such good control on, yet it's what everyone wants to see when they see these kind of beautiful reconstructions and 3-D pictures of dinosaurs is, what was their color? Now, color reconstruction is something that many of the pigments that were in the original skin of the dinosaur, if you do have this remarkable skin preservation, those pigments fade and disappear with time. So, most artists who work with scientists, the color red. If blood is fluxed through vesicles and veins that are near to the surface of a dinosaur, then that skin would have turned red from the blood. But the other pigments, which we know there would have been many, blue, and green, and orange, and all kinds of beautiful pigmentation. We don't have a lot of good control on that. So, often times the morphologies and the skeletal structure and the reconstructions we see that are so striking for us, especially in Hollywood for the movies, most of those are fanciful. And they're linked to reality, but we don't necessarily always have good evidence for the coloration. Now, another piece of evidence is one that might be a little uncomfortable to think about but it's basically, it's dinosaur do-do. It's dinosaur defecation. Dinosaurs were large and there were a lot of them, and you know, there's just the fact of life. There was a lot of dinosaur poop that was created throughout the entire process of having dinosaurs both in the marine environment and in the terrestrial environment. So fossilized dinosaur poop, fossilized dinosaur defecation, is a really important piece of information about the dinosaurs. And not only is the composition of the fossilized defecation important to us, but also the distribution of it, and then linking it to what it was eating and what it was doing. Going forward, again, we do this in the modern, looking at stool samples is an important way for doctors to be able to understand human health. So these aren't foreign things to us. We have a unique name for these fossilized dinosaur defecation deposits, and they're called coprolites. The coprolites are very abundant throughout the world, wherever you get these dinosaur remains. Another important part of dinosaur forensics, if you will, is the dinosaur egg. So dinosaurs had, some of them had a leathery outer membrane, but others actually had true eggs that were very similar to some of the hard shelled eggs that modern day chickens have. So dinosaur eggs are very well preserved in some places. Now of course, a chicken egg if you'll make an analogy to that, it's a pretty sturdy object right. You can crush it, but it's actually quite strong. And if you were to have a grouping of chicken eggs put into some kind of depression or pocket that was protected from too much force that would crush them, you can actually get full eggs nicely persevered in your shopping bags, right? Because you make it from the grocery store home and the eggs are still in one good piece. So fundamentally, the dinosaurs did this for us by laying many of their eggs in nests. So as an example the hadrosaurs in the cretaceous would build nests where there'd be an elevated platform of mud, perhaps as high as half a meter to a meter. It had a depression in the middle. It looked kind of like a little volcano, and in the middle of that depression [COUGH] they would lay their eggs, and sometimes they would partially cover those eggs. And if the eggs in a mud nest where to be inundated, say by a flooding event from a stream or perhaps the dinosaurs would place sediment into the nest. Some kind of an event that would take place to add a covering of sediment over the top. You have a ready made egg container that's going to preserve those eggs through geological time and prevent them from being destroyed. As we see in this image, the eggs not only are preserved in the outer shell. But remarkably, inside we have the embryonic stages that are well fossilized, and we can see there the internal vertebrate skeleton of the dinosaurs as well. Well, recently too, analyses of the inner portions of the dinosaur eggs have shown that, remarkably, there are bacterial cells that are preserved inside of the eggs as well. And we see those in modern day chicken eggs in addition. So the idea that dinosaur eggs are very well fossilized. And some of the most famous sights of these come from Mongolia, but they are in other places as well. Is another piece of forensic evidence that we put together to have such a robust history. Now in the modern day, if there's a crime, and one of the first things they do on TV of course is they look outside the window in the dirt and look for the track of the culprit who'd done the murder, climbed out the window. And they have this beautiful print of their boot, which of course, they make a plaster cast of, and then they go off trying to find where that boot was manufactured and who sold it to the bad guy. Well, we do the same thing with the dinosaurs. There are many examples of what we call dinosaur tracks and dinosaur traces. And so one of the most well developed ones of these actually comes from Connecticut, as we see in this picture. And there was a sauropod, one of the long-neck saurischian herbivorous dinosaurs, that was walking as part of a herd across a shallow part of the margin of the ocean, where you had muds and sands, and their body weight would have created a very deep depression of their foot print. And they kept marching forward as we can see in this image, those dinosaur footprints are extremely well preserved. And from the footprints, by measuring the diameter and the size of the footprints, how deep the footprint went into the sediments, and then the distance between footprints, we can reconstruct body size, age, and the speed at which the dinosaurs were walking or running. And in fact, there are many examples, as we see in this image, where we have the predator-prey relationship fossilized in the footprints. And so you can see the large footprints, in this case, of a saurichian T-Rex dinosaur that was chasing some kind of smaller, probably herbivorous, dinosaur. You can see there, the example of the large footprints and the small footprints. Now, of course, I've saved towards the end, one of the most remarkable lines of evidence and that's the fossilized dinosaur bones. And so hopefully everyone, if you haven't seen them in person at least you've seen them through these kinds of images. These remarkable, entire full skeletons that have been recovered from the fossil record. And these continue to be found, many students make the assumption that, well, all dinosaurs have been found and therefore the field is now working on dinosaur bones that are collected and hiding in drawers in some kind of museum. That couldn't be farther from the truth. On a daily basis new dinosaur finds are occurring all the time. The remarkable preservation of these bones, it's not just the mineral replacement that is found, but actually the full bone itself. There are scientists that have found actual pieces of connective tissue. Which are still exhibiting the pigment of the red blood cells and then those connective tissues are remarkable, right? And these things are on order of 90-100 million years old. So it's crime scene investigation of the demise of the dinosaurs, and the life history, and the habits of the dinosaurs. It's a very exciting, very robust, very integrative and cutting edge type of field. And as science and technology moves forward and our ability to have advancements in human medicine go forward, those same tools that are derived from those areas of scientific advancement can be used directly to the fossil record. [MUSIC]
