Geologic Time Table Flashcards
Involves vast amounts of times - millions or billions of years
Magnitude of geologic time
Describes the processes in the geologic time
Gradual
The basis of the division of the time scale
Life-forms
Geologic time divisions called
Geochronological units
Most life-forms found as
Fossils
Divisions in the geologic time scale
Eons, eras, periods, epochs
Longest subdivision; based on the abundance of certain fossils
Eons
The four geologic eons
Phanerozoic, Proterozoic, Archaean, Hadean
The four geologic eons collectively called
Precambrian
Percentage that the Precambrian encompasses in the geologic time
about 88%
Next to the longest subdivision; marked by major changes in the fossil record
Eras
Three geologic eras
Paleozoic, Mesozoic, Cenozoic
The basic unit of geologic time
Period
Large interval units of time that encompasses smaller intervals of time
Periods
Paleozoic meaning
Old Life
Mesozoic meaning
Middle Life
Cenozoic meaning
New Life
Began with the breakup of one supercontinent and the formation of another; plants became widespread; vertebrate animals colonized the land; abundant ocean-dwelling organisms that required oxygen to live
Paleozoic era
Six divisions of the Paleozoic era
Permian, Carboniferous, Devonian, Silurian, Ordovician, and Cambrian
Major extinction; reptiles diversify
Permian period
First reptiles, trees, seed ferns
Carboniferous period
First amphibians; fish diversify
Devonian
First vascular plants
Silurian
Major diversification of animal life
Ordovician