It's easy to confuse paleontology with archaeology. Archaeology is the study of ancient people and what they left behind. Archaeologists study how people used to live together, what tools they made, and where they lived. Paleontology is similar and uses many of the same techniques, but it involves studying ancient animals and plants.

Much of the work in these two related sciences is similar. Both kinds of work involve careful digging with delicate tools, detailed laboratory work, and research. However, humans have populated Earth for only about the last 150,000 years. Complex animals and plants have been around three thousand times longer - more than 500 million years!

A paleontologist is a scientist who specializes in paleontology. Paleontology is the study of ancient life - plants and animals usually more than 10,000 years old. Everyone seems to focus on dinosaurs when they think of paleontology - probably because dinosaurs were living monsters. As skeletons of these giants are uncovered and understood, our vision of what's possible expands.

The first dinosaurs were discovered in England in the early 1800's. They were Megalosaurus and Iguanodon, and these were the first dinosaurs to be recognized and described as something people had not seen before. Soon, dinosaurs began popping up in North America, Europe, Asia, and eventually Africa and South America. Now dinosaurs have been found on all continents, including Antarctica. It seem that wherever we have the right-aged rocks, dinosaurs were preserved - and busting out all over.

Animals and plants that die are sometimes buried in sediment - sand or silt deposited by water, wind, or ice. As months and years and then millions of years pass, more and more sediment piles up, and hardens into sedimentary rock. Because of the short time that humans have been around, only a small layer of the earth's crust contains archaeological deposits. But paleontological deposits can be found throughout the earth, in nearly every kind of sedimentary rock. Since so much more sedimentary rock is filled with fossils than with human remains, a paleontologist has much more to find than an archaeologist!

Facts, Theories & Debates

Paleontology is a science of discussion and argument. For paleontologists, this is fun, and it helps their minds expand and think of new possibilities. Plenty of subjects are under debate, and it's interesting to see how the same fossil evidence is used to support various positions.

Also, as more and more evidence is discovered, hypotheses change. Just as our concept of the shape of the earth changed (and finally was proven when we could see it from a distance), paleo debates shift over time from hypotheses to theories to facts. (Sometimes this happens in geologic time!)

Popular T. rex debates: Wishbones, scavenger / predator, T. rex speed, gender.

Paleontologists usually start out as either geologists, who study the earth's layers, or biologists, who study living animals, or botanists, who study plants. They also have to know about chemistry - the building blocks of life. And physics - how our world works. And engineering - the design and building of structures. Once they know these ways of thinking, they can decode what they find in the earth's layers.

Here's a story to show how paleontologists think. You can do this, too, as soon as you discover a question that needs an answer. Our example is: are birds the descendants of dinosaurs?

1. Sir Richard Owen, in 1842, noticed that some dinosaur's feet looked like birds' feet. He was the guy to coin the term Dinosauria.
2. In 1861, Archaeopteryx was discovered. It looked like a bird with some dinosaur parts - but scientists decided that since it had "bird-only" characteristics (feathers, wishbone), and dinosaurs did not, the two could not be related. They said Archaeopteryx was the "missing link" to something else.
3. Nobody thought much about this situation for 100 years, until John Ostrom, in the 1960s, noticed that Deinonychus - definitely a dinosaur - had bird characteristics. At this same time, Bob Bakker postulated that theropods were just too much like birds to be slow, boring reptiles. Dinosaurs got a face lift when Bob started drawing them with feathers.
4. In the next decades, dinosaur fossils were found with more and more bird characteristics, including foot and wrist and tail configurations. And wishbones. And feathers. With each new connection, the "bird-only" definition shrank down to nothing.
5. Finally, most scientists looked at the evidence and agreed that the two groups - meat-eating dinosaurs and birds - were so similar that they had to be very closely related.
6. The geologic timeline shows when birds first appeared. The way it works is that birds and some later theropods developed at the same time, from similar theropod ancestors.
7. The big deal: does this mean that the name Dinosauria is actually inaccurate? The problem is that theropod dinosaurs and other dinosaurs aren't as closely related as theropods and birds! This means that maybe long-necked sauropods are SOMETHING; Triceratops, duckbills, and others in their group are SOMETHING ELSE; and theropods and birds are SOMETHING ELSE AGAIN.

This story shows how one hypothesis after another was developed as evidence mounted. Scientists used biology, geology, and evolution to finally arrive at their conclusion - and more new questions.