The Geologic Time Scale L1

• The Geologic Time Scale is a system used by scientists to divide Earth's history into different time periods based on major geological and biological events.
• The Geologic Time Scale is divided into several hierarchical divisions, including eons, eras, periods, epochs, and ages.
• The largest division of the Geologic Time Scale.

  Eons
• There are four eons recognized: the Hadean, Archean, Proterozoic, and Phanerozoic
• The Phanerozoic eon is the most recent eon in the geologic time scale.
• Eras represent major intervals of time within an eon
• The three eras of the Phanerozoic eon are the Paleozoic, Mesozoic, and Cenozoic.
• Each era is characterized by significant geological and biological events
• Periods are subdivisions of eras and represent smaller intervals of time.
• the Paleozoic era is divided into six periods: the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian.
• Epochs are even smaller divisions of time within periods.
• Epochs represent relatively short intervals of time and are characterized by specific geological and biological events
• The current epoch is the Holocene, which began around 11,700 years ago.
• Ages are the smallest divisions of the Geologic Time Scale.
• Ages are used to further refine the timing of events within epochs and periods
• Hadean Eon: Formation of Earth, intense volcanic activity.
• Archean Eon: First evidence of life, formation of continents.
• Proterozoic Eon: Oxygenation of Earth's atmosphere, development of complex life forms
• Paleozoic Era: Explosion of life forms in the oceans, colonization of land by plants and animals
• Mesozoic Era: Age of dinosaurs, emergence of flowering plants
• Cenozoic Era: Rise of mammals, evolution of humans
• Cambrian Period: Rapid diversification of marine life, emergence of complex organisms.
• Jurassic Period: Dominance of dinosaurs, evolution of birds
• Holocene Epoch: Development of human civilizations, significant climate changes