Earth was created around 4.6 billion years ago. Since
then there have been supercontinents, dinosaurs, shark
eating reptiles, birds of terror, and humans. To
keep track of the earth's history, the timeline was
divided into Eras, Periods, and Epochs. There are
three Eras, the Paleozoic, Mesozoic and Cenozoic.
These are then broken into Periods, which are then
divided into the Epochs. The complete breakdown of the
geologic time scale is pasted below. This is the one
published by the Geological Society of America in
2009. http://www.geosociety.org/science/timescale/
There
are many other ways to represent the history
of the earth. Some people use a spiraling
timeline so you can focus on history since
life began and leave ancient history in the
distance. The Time scale below represents
this.
 http://www.caveofthemounds.com/geotimeline.htmAnother method used to represent the geologic timescale is the clock diagram. This places all 4.6 billion years onto a 12 hour clock. This figure helps put the length of time that humans have walked the earth into perspective.  http://serc.carleton.edu/NAGTWorkshops/time/TLJCfindings.html |