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Formation (4.6 Billion Years Ago):
- Earth formed from the dust and gas surrounding the young Sun. Over millions of years, accretion and collisions led to the creation of our planet.
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Hadean Eon (4.6 - 4 Billion Years Ago):
- During this time, Earth was bombarded by asteroids and comets, and volcanic activity was intense. Conditions were harsh, and the atmosphere began to form.
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Archean Eon (4 - 2.5 Billion Years Ago):
- Simple life forms, such as bacteria and archaea, emerged in the oceans. These early organisms were the first signs of life on Earth.
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Proterozoic Eon (2.5 Billion - 541 Million Years Ago):
- Oxygen levels in the atmosphere increased due to photosynthetic bacteria. Multicellular life forms evolved, and the first complex organisms appeared.
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Paleozoic Era (541 - 252 Million Years Ago):
- Major diversification of life occurred during this era. Fish, plants, insects, and the first land animals emerged. The era ended with the largest mass extinction, the Permian-Triassic Extinction.
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Mesozoic Era (252 - 66 Million Years Ago):
- Often referred to as the "Age of Dinosaurs," this era saw the dominance of reptiles. Dinosaurs evolved, and birds and mammals appeared. The era ended with another mass extinction event, including the extinction of dinosaurs.
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Cenozoic Era (66 Million Years Ago - Present):
- Mammals became the dominant land animals. The first primates appeared, leading to the evolution of humans. The era is divided into the Paleogene, Neogene, and Quaternary periods, with the latter encompassing the development of Homo sapiens and the last Ice Age.
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Human History (2.5 Million Years Ago - Present):
- Early humans evolved, developed tools, and migrated across the globe. Agriculture emerged, leading to settled societies. Technological advancements, civilizations, and the rise and fall of empires characterize more recent human history.
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Modern Environmental Challenges (Industrial Revolution - Present):
- The Industrial Revolution brought about significant technological advancements but also led to environmental challenges, including pollution, deforestation, and climate change.
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The Anthropocene (Unofficial, Proposed Epoch - Present):
- Some scientists suggest that human activities have had such a profound impact on Earth that we have entered a new geological epoch called the Anthropocene.
The story of Earth is ongoing, with humans playing an increasingly influential role in shaping the planet's future. The study of Earth's history helps us understand the processes that have led to the diverse and dynamic world we know today.