How can we know that there were dinosaurs millions years ago? How do we know how they looked?
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> How do we know how they looked?
You’d be surprised at how many things we can deduce based on just bones embedded in old rocks. Paleontologists are detectives of the past, and with the growth of technology we have improved remarkably in being able to fit pieces of the past together.
Here’s an example: If you’re presented with a segment of the leg of a Utahraptor, how would you explore further what not only this individual raptor was like, but all raptors in general?
Look at the structure of the bone, is it slanted? Does it look thick and well built? That’s evidence that it was a predator, because it had to evolve powerful legs in order to pursue prey. But what else? Look at the endings of the bones: Are they chipped? Slotted? Do they have a socket? You can remodel what the rest of the leg may have been like using computers which will draw thousands of models that potentially fit the leg sample you have.
But let’s take it a step further, how would you find out what this dinosaur ate? Well we know that it was likely a predator, so it’s likely that it also had sharp or serrated teeth made for ripping through flesh and bone. But we can analyze the setting in which this fossil was found. Was it found in a grassy environment? A forested one? A hot and dry desert? This fossil was found in Utah (hence the name), and millions of years ago, Utah used to be an open woodland and river-forest area. We know that the herbivores in these areas had to be fast and nimble, they were probably quadrupedal and had sharp eyesight to look for predators and other prey. And based on the size of the fossil we found for Utahraptor, we know it wasn’t enormous and likely just hunted prey that was smaller or slightly bigger than it, so no gigantic animals like brachiosaurs or sauropods.
But let’s take it one step even further: How do we find out what this dinosaur behaved like, and how it really looked? We can extract samples of genes from the fossil we found! Because all living organisms use the same mechanism for storing information (DNA), we can analyze the genetic makeup of this dinosaur to find out more. You load your sample of damaged but viable DNA into a computer and it begins churning away. You see traits associated with social intelligence (which suggest that this animal likely hunted in a pack), you see traits for large forward facing eyes which reveal that this animal was likely a pursuit predator and chased prey instead of scavenging, and, oh no, the rest of the DNA is too damaged or missing and the computer can’t process it.
But that’s OK. From just one tiny little leg you were able to discern information about not just what the leg looked like, but what this dinosaur *ate* and behaved like. And the good news? There are so many more fossils out there that reveal even more information. And you can collaborate with other bright minds to draw hypotheses about this dinosaur and countless other dinosaurs you come across. And with the help of technology, it becomes easier to see and model all these things.
The moral of the story is that there’s a lot more beneath the surface, and with fossils, just what you see is not the end all presentation.
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