Overview

The fossil record spans three-quarters of Earth history but forms a coherent whole only since the time that animals with skeletons appeared at the beginning of the Cambrian period. Both the origin of life and the origin of the major groups of animals remain unknown. The seafloor became heavily populated with animals in Cambrian time, and the lands were colonized in the Silurian Period. Organic communities have become more complex through geologic time, but not in a linear fashion. Extinction of species is normally counterbalanced by speciation, but at times it has prevailed, and during the great biotic crises some communities were reduced to low levels throughout the world, and major groups of organisms, such as the dinosaurs and ammonites, were lost. That part of the record is a reminder that organisms exist at the tolerance of the environment, and that this environment, throughout geologic time, has exhibited variations of a nature and magnitude outside the realm of human experience.

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  	Bones, Bones, Dinosaur Bones by Byron Barton Use high-quality literature to observe nature and encourage children to act and think like scientists. $24.95 Big Book | Grades Pre-K-3

  
  Bones, Bones, Dinosaur Bones
  Grades Pre-K-3 $24.95
  
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  Dinosaur Teeth by Susan H. Gray REVIEWS:   10/1/07 Library Media Connection With its fabulous photography and large print, this content vocabulary building set gives our youngest paleontologists a fine introduction to all things dinosaur while providing a motivating framework for learning to read nonfiction. In each book, a word hunt immediately follows the table of contents, giving children new words with a pronunciation guide and a corresponding photo. Children learn the vocabulary as they read, $14.00 You save: 30% Library Binding | Grades 1-2

  
  Dinosaur Teeth
  Grades 1-2 $14.00
  

What Color Were the Dinosaurs?
Scientists' theories vary about what color skin dinosaurs may have had.

What Did Dinosaurs Eat?
Scientists can tell whether a dinosaur was a plant-eater, a meat-eater, or both, by studying its teeth.

Digging Dinosaurs
Dinosaurs didn't just walk the Earth long ago -- they lived underground too! That's what scientists learned when they discovered the first species of a burrowing dinosaur. The discovery will go on display this summer at Montana State University's Museum of the Rockies.