To see our still very incomplete overview of the history of life on Earth, click on one of the following links or images.
We even have a rough idea of geological timescales on the moon and Mars.
The colours associated with each have no other significance, other than to brightly label jars of geological specimens, and brighten up the Palaeos timeline pages.
By convention, the oldest units are at the bottom, the youngest at the top (representing the order of deposition of strata, as this diagram derives originally from 19th century geology) .
These divisions are pretty arbitrary, like all such man-made classifications, but they at least can serve as useful labels, so we can orientate ourselves in our journeys through deep time.
So the Paleozoic, the era of "ancient life" is characterized by fossils of invertebrates, primitive tetrapods, etc; the Mesozoic or era of "middle life", by fossils of dinosaurs etc, and the Cenozoic or era of "recent life" by mammals and modern plants and invertebrates.
These eras are divided into periods, the system of which was established by the middle of the last century.
The periods are in turn divided into epochs, and the epochs are divided into ages called ages.
The Discovery of Deep Time Pre-modern concepts of Time Geology and the discovery of Deep Time Geology and the discovery of Deep Time - Reading List Geological Timescale Stratigraphy Radiometric dating Detailed Geological Timescale Precambrian Time Phanerozoic Eon Geological Time Units The Geon Planetary Timescales Lunar Geological timescale Martian Geological timescale Glossary References Quaternary Time Historical Time Although (as explained in the parent unit (more inclusive unit) of this topic) there are many possible timescales (which range from the very long (billions of years) to the very short) , Geological time, which deals in millions or tens of millions of years, is the main focus here at Palaeos.
Therefore this page provides the starting point for an overview of Earth history.