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.
| Geologic Time Scale | ||||
| Era | Period | Epoch | Significant Events | Million Years Before Present |
| Cenozoic | Quartenary | Holocene | recorded human history, rise and fall of civilizations, global warming, habitat destruction, pollution mass extinction | 0.01 |
| Pleistocene | Homo sapiens, ice ages | 1.6 | ||
| Tertiary | Pliocene | global cooling, savannahs, grazing mammals | 5.3 | |
| Miocene | global warming, grasslands, Chalicotherium | 24 | ||
| Oligocene | 37 | |||
| Eocene | modern mammals flourish, ungulates | 58 | ||
| Paleocene | 66 | |||
| Mesozoic | Cretaceous | last of age of dinosaurs, modern mammals appear, flowering plants, insects | 144 | |
| Jurassic | huge plant-eating dinosaurs, carnivorous dinosaurs, first birds, breakup of Pangea | 208 | ||
| Triassic | lycophytes, glossopterids, and dicynodonts, and the dinosaurs | 245 | ||
| Paleozoic | Permian | Permian ends with largest mass extinction in history of Earth, most marine inverterbrates extinct | 286 | |
| Pennsylvanian | vast coal swamps, evolution of amniote egg allowing exploitation of land | 320 | ||
| Missipian | shallow seas cover most of Earth | 360 | ||
| Devonian | vascular plants, the first tetrapods, wingless insects, arachnids, brachiopods, corals, and ammonite were also common, many new kinds of fish appeared | 408 | ||
| Silurian | Coral reefs, rapid spread of jawless fish, first freshwater fish, first fish with jaws, first good evidence of life on land, including relatives of spiders and centipedes | 438 | ||
| Ordovician | most dry land collected into Gondwana, many marine invertebrates, including graptolites, trilobites, brachiopods, and the conodonts (early vertebrates), red and green algae, primitive fish, cephalopods, corals, crinoids, and gastropods, possibly first land plants | 505 | ||
| Cambrian | most major groups of animals first appear, Cambrian explosion | 570 | ||
| Proterozoic | stable continents first appear, first abundant fossils of living organisms, mostly bacteria and archeobacteria, first eukaryotes, first evidence of oxygen build-up | 2500 | ||
| Archean | atmosphere of methane, ammonia, rocks and continental plates began to form, oldest fossils consist of bacteria microfossils stromatolites, colonies of photosynthetic bacteria | 3800 | ||
| Hadean | pre-geologic time, Earth in formation | 4500 | ||
BibliographyFoster, Robert. Geology. 3rd ed. Columbus, OH: Charles E. Merrill, 1976. Stanley, Stephen. Earth and Life Through Time. New York: W. H. Freeman, 1989. Toulmin, Stephen and June Goodfield. The Discovery of Time. New York: Harper & Row, 1965. Internet Resources |