Download or read book The Paleozoic Era written by John P. Rafferty Associate Editor, Earth Sciences and published by The Rosen Publishing Group, Inc. This book was released on 2010-08-15 with total page 341 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explores the evolutionary advances of the Paleozoic period including the development of plants with seeds, shelled eggs, and organisms capable of breathing air.