Paleontology is the study of the history of life on Earth. It focuses on fossils. A fossil is the remains of a long-dead animal or plant.

There are mainly two kinds of fossils. In one case, animal, or plant matter is replaced by rock over time. The remains still keep their shape. In the other case, the fossil is actually an impression. It can be a footprint, for example. Or it can be the outline of a body pressed into mud. Over time, the earth and mud turn to rock. Yet, the impression remains.

Paleontologists study all species, or kinds of animals and plants. They study species that still exist. They also study extinct species. Extinct species are ones that have died out. Dinosaurs are one example.

Fossils show how living things evolved, or changed, over time. They also show how one species evolved out of another. For example, paleontologists believe whales evolved from land animals. They think this because of the fossils of certain extinct animals. These animals are closely related to whales. Like whales, they lived in the ocean. Yet, they still had legs. Over time, those legs disappeared. Then, whales developed.

Subdisciplines of Paleontology

There are several different kinds of paleontology, called subdisciplines. Each looks at a different kind of fossil.

Vertebrate Paleontology

Vertebrate paleontology is one kind of paleontology. It is the study of fossils of animals with backbones. Vertebrate paleontologists have dug up the fossilized skeletons of many ancient animals. For example, they have found many kinds of dinosaurs.

Invertebrate Paleontology

Invertebrate paleontology is the study of the fossils of animals without backbones. Such animals are called invertebrates. They include things like crabs, shrimp, sponges, and worms. Invertebrates do not have bones. They do leave things like shells behind, though. Or, they leave an impression of their soft bodies.

Paleobotany

Paleobotany is the study of fossils of ancient plants. These can be impressions of plants left on rocks. Or, they can be parts of plants preserved in rock. Such fossils show how plants have evolved.

Micropaleontology

Micropaleontology is the study of fossils of microscopic organisms. These living things are very, very tiny. Most are so small they cannot be seen with the eye alone. They can only be seen with microscopes.

History of Paleontology

People around the world have been finding fossils for thousands of years. They did not always understand what they were, though.

Paleontology as we know it began in the 1700s. At that point, scientists were carefully studying fossils for the first time.

Scientist Charles Darwin changed paleontology greatly. In the 1850s, he showed that new species evolve over time. Over millions of years, one species can change and become a new species. Animals living today are related to species from the distant past. This can be true even when they look very different.

After Darwin, paleontologists saw fossils in a new way. They began to make connections between fossils and living animals. These connections helped show how ancient animals lived. They also showed how one kind of animal evolved into another.

Take the example of the Archaeopteryx. The Archaeopteryx lived many millions of years ago. Paleontologists discovered it had wings like a bird. Yet, it also had teeth like a dinosaur. That made paleontologists decide the Archaeopteryx was a very early kind of bird. Over time, dinosaurs evolved into birds. The Archaeopteryx was a first step in that direction.

In the late 1800s, scientists discovered radioactivity. Radioactive objects send out a certain amount of energy over time. By measuring how much radioactive material a fossil has, scientists can guess the fossil's age. This is called radiometric dating.

Paleontology Today

Today, paleontologists use many advanced tools. They study the smallest fossils with microscopes. They use x-ray machines to look inside fossils. Computers help them figure out how extinct animals looked and moved.

Paleontologists still make important discoveries with simple tools, too. They still use pickaxes and brooms. Around the world, many are still digging away. Each is hoping to learn more about the history of life on Earth.