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Glossary of Terms

Cretaceous: The most recent of the three periods of the Mesozoic Era – the “age of dinosaurs.” Dinosaurs lived during a relatively short time period, (relative, that is, to the geologic time scale, not to humans) . Dinosaurs roamed the Earth for about 175 million years. This is not a long time considering the Earth is 4.6 billion years old. Humans have been around an even shorter time–less than 2 million years

The Mesozoic Era (250 to 65 million years ago) is divided into three periods:
1. the Triassic (250-193 million years ago);
2. the Jurassic (193-136 million years ago);
3. the Cretaceous (136-65 million years ago).

Dinosaur: Extinct ancient land animals that lived on earth between 240 and 65 million years ago, a period of 175 million years. (The term dinosaur is Greek for "Terrible Lizard" although now scientists believe they are only distantly related to reptiles.)

Fossils: Remains of ancient life, these are the basic sources of information to a paleontologist. These can be bones, shells, or teeth (or their impressions), impressions of plant stems and leaves, burrows, or tracks. Soft tissue is rarely preserved as a fossil. Not all fossils are dinosaur fossils. In fact, dinosaur fossils, although among the largest fossils, make up a small percentage of fossils studied. The most numerous fossils are invertebrates (without a backbone), such as animals with shells, and remains of plants.

Hadrosaur: from the Greek, meaning "massive lizard;" a group of bird-hipped dinosaurs that lived during the Cretaceous period. Hadrosaurs had long, flat snouts, which accounts for their nickname “duck-billed,” and many also had crested skulls.

National Monument: public land areas set aside by the President or Congress to protect areas of historic or scientific importance. Grand Staircase-Escalante was proclaimed a national monument in 1996.

Paleontologist: Scientists who study paleontology. They are “detectives” working with “clues” such as fossils, to reconstruct the history of the earth and the plants and animals that have existed over millions of years.

Paleontology: Scientific study of earth’s past life (from Paleos+Ontos+Logos + Ancient Life Study). Paleontology integrates biology and geology. It excludes humans and human artifacts and should not be confused with either anthropology or archaeology, which both study ancient humans. Paleontology can answer questions about what plants and animals existed in a certain ancient time and how they interacted with each other and the land. Paleontology also can reconstruct the history of life and the earth over millions of years.

Parasaurolophus: a genus of dinosaurs that belongs to the family of hadrosaurs, or duck-billed dinosaurs. Remains of only a few species of this dinosaur have been found.

Plateau: an elevated land area with a flat top that is wider than it is high (a butte is about as wide as it is high, and a pinnacle is higher than it is wide.)

Species: the basic unit of classification among living things. A genus (pl. genera) comprises a group of similar species. Similar genera are placed into families.


Last updated: 10-23-2009