Judith Fitzgerald, age 13, of New Bedford, Mass., for her question:
WHAT IS PALEONTOLOGY?
Paleontology is the science of the study of fossils. Fossil remains of animals and plants can be found in layers of sedimentary rock. Sedimentary rocks were formed in the earth when mineral matter settled out of the air, ice or water.
The animals and plants that are now fossils lived when the rocks were formed. They were buried and preserved as the layers of rock piled up century after century.
Paleontologists learn what kind of life existed during various periods of the earth's history by studying fossils.
The oldest known fossils are one celled plants that lived at least 3.1 billion years ago. The fossil record shows a gradual increase in the complexity of animals and plants. This gradual change in body form is called "evolution."
Paleontology is important in the study of geology. The age of rocks may be determined by the fossils in them. Fossils also tell whether rocks were formed under the ocean or on land.
Most rocks that contain land animals and land plant fossils were formed on land. The knowledge of which rocks were formed under the ocean helps scientists map the world as it was millions and even billions of years ago. Such scientists are called paleographers.
There are three main branches of paleontology:
(1) invertebrate paleontology, which deals chiefly with fossil insects and shells;
(2) vertebrate paleontology, which is the branch that is concerned with extinct fishes, amphibians, reptiles, birds and mammals;
(3) paleobotany, which is the study of fossil plants.
Paleontology also aids in the location of oil. Oil is often found in rocks that contain certain fossils. Oil companies use such fossil information as a clue to where oil might be. Sedimentary rocks lie beneath about three fourths of the land surface of the earth. Most of the rocks contain fossils.
When the scientist reaches an area in the rock which he feels may contain fossils, he begins searching places where the soil has worn away from the rocks. If he wants to study plants or invertebrates, he splits open rocks to find fossils inside. To study larger animals, he searches for fragments of bones or teeth that stick out of the ground.
As he uncovers the fossil, the paleontologist protects it with shellac or plastic. Then he covers it with strips of wet paper. Next he adds a series of burlap strips dipped in plaster of Paris to form a jacket that protects and supports the fossil.
The paleontologist may strengthen a large specimen by putting sticks or timbers inside the jacket.
When the exposed surface is completely covered with hardened plaster, the whole fossil is rolled over. The scientist places another jacket on the other side. It is then ready to be packed and shipped to a museum.