Eons:

* Precambrian Eon: The oldest eon, spanning from the formation of the Earth (around 4.5 billion years ago) to the beginning of the Paleozoic Era (around 541 million years ago). It's further divided into three eras: Hadean, Archean, and Proterozoic.

* Phanerozoic Eon: The most recent eon, starting from the beginning of the Paleozoic Era and extending to the present day. It encompasses the time when complex life forms emerged and diversified.

Eras:

These are further divisions within the Phanerozoic Eon:

* Paleozoic Era: "Old life," ranging from 541 to 252 million years ago. Characterized by the emergence of many animal phyla, including fish, amphibians, reptiles, and early insects.

* Mesozoic Era: "Middle life," ranging from 252 to 66 million years ago. Known for the dominance of dinosaurs, the rise of mammals and birds, and the appearance of flowering plants.

* Cenozoic Era: "Recent life," starting from 66 million years ago and continuing to the present. Marked by the diversification of mammals and the rise of humans.

Periods:

These are further divisions within each Era, each representing a significant geological or biological event:

Paleozoic Era: Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian.

Mesozoic Era: Triassic, Jurassic, Cretaceous.

Cenozoic Era: Paleogene (Paleocene, Eocene, Oligocene), Neogene (Miocene, Pliocene), Quaternary (Pleistocene, Holocene).

Epochs:

These are further subdivisions within the Cenozoic Periods, particularly the Quaternary.

It's important to remember that these divisions are based on significant geological and biological changes, not absolute time intervals. The boundaries between these subdivisions are often subject to debate and revision as new data emerges.