Geological epochs are divisions of geological time that help scientists understand the Earth's history. They are part of a larger hierarchy that includes eons, eras, and periods. Each epoch is characterized by significant changes in the Earth's climate, geography, and the evolution of life, allowing researchers to study how these factors influenced the planet over millions of years. The current geological epoch is the Holocene, which began around 11,700 years ago after the last major ice age. Before the Holocene, the Pleistocene epoch was marked by repeated glacial cycles. Understanding these epochs helps scientists track the development of ecosystems and the impact of events like mass extinctions.