The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
All other sections in this Literature Study Guide are owned and copyrighted by BookRags, Inc.
The Phanerozoic Eon represents geologic time from the end of Precambrian time, approximately 544 to 570 million years ago (mya), until the present day. As such, the Phanerozoic Eon includes the Paleozoic Era, the Mesozoic Era, and the current Cenozoic Era. The Phanerozoic Eon and constituent eras are then further divided into 12 geologic periods.
The Phanerozoic Eon derives its name from phaneros, meaning visible or evident, and zoon, meaning life. Although early life existed in Precambrian time—including prokaryotes (e.g., bacteria) and eukaryotes (organisms with a true nucleus containing DNA)—the onset of the Phanerozoic Eon marks the start of complex life (e.g., invertebrates) found in the Cambrian Period.
In terms of the fossil record, the Phanerozoic Eon represents not the origin of life, but of life capable of leaving extensive fossil remains (e.g., organisms with shells, etc.). Fossilization refers to the series of postmortem (after death) changes that lead to replacement of minerals in the original hard parts (shell, skeleton, teeth, horn, scale) with different minerals, a process known as remineralization. Infrequently, soft parts may also be mineralized and preserved as fossils. Fossils of soft bodied Precambrian time fossils have been found but, as expected, they are rare and present an incomplete evolutionary record.
Archean; Cretaceous Period; Dating Methods; Devonian Period; Eocene Epoch; Evolution, Evidence Of; Fossil Record; Fossils and Fossilization; Historical Geology; Holocene Epoch; Jurassic Period; Miocene Epoch; Mississippian Period; Oligocene Epoch; Ordovician Period; Paleocene Epoch; Pennsylvanian Period; Pleistocene Epoch; Pliocene Epoch; Proterozoic Era; Quaternary Period; Silurian Period; Tertiary Period; Triassic Period