Pub. date: 2006 | Online Pub. Date: September 15, 2007 | DOI: 10.4135/9781412952453 | Print ISBN: 9780761930297 | Online ISBN: 9781412952453| Publisher:SAGE Publications, Inc.About this encyclopedia
The origin and diversity of life on Earth has been one of humankind's most enduring sources of curiosity. The questions of,“who, how, when, where, and why” are still widely debated. These questions cross the boundaries between science, philosophy, and religion. It is not the intent of this entry to settle this controversy. Rather, it will look at these topics from the standpoint of science based on our current level of knowledge and understanding. This entry is arranged chronologically by era. The time spans discussed are compared to their relative positions from the “recent” end of a 100-meter-long rope to illustrate the quantity of time discussed and its distance from the present. Dates presented herein are primarily from the revised stratigraphic chart of the International Commission on Stratigraphy, 2004. The abbreviation mya means “million years ago.” One feature of the fossil record is that preserved fossil localities increase in direct proportion ...