PCB 4674C Lecture Notes - Lecture 17: Precambrian, Cyanobacteria, Radiometric Dating
Document Summary
Ii fossils or, the record of life preserved in rocks. Fossils are the remains of once-living organisms or the traces of their activities: initially, fossils were viewed as manifestations of ideal forms in rocks, but were not considered as ever having lived. The term fossil originally applied equally to true organic remains, and to crystals and other organized natural objects. Fossil is from the latin verb fodere to dig . Fossils were things that were dug up. Iii the history of life part 1: the precambrian and the origin of life. The earth (as you know) is approximately 4. 5 billion years old: 4. 6 x 109 or 4,600,000,000 years old, this date based on radiometric dating of meteorites and moon rocks. The age of the earth is considered to be approximately the same as the age of the solar system. The earliest suggestive, but not definitive evidence for life on earth comes from "chemical" fossils.
