Timeline of Earth
Introduction
The timeline of Earth is a journey through geological and biological evolution, highlighting significant events that have shaped the planet.
Timeline
Geological and Biological Events
| Era | Period/Epoch | Date | Event |
|---|---|---|---|
| Precambrian | - | 4.6 billion years ago | Earth forms from the solar nebula. |
| - | - | 4 billion years ago | Oldest known rocks form. |
| - | - | 3.5 billion years ago | First evidence of life: prokaryotic cells (bacteria and archaea). |
| - | - | 2.5 billion years ago | Great Oxygenation Event: Oxygen begins to accumulate in the atmosphere. |
| Paleozoic | Cambrian | 541 million years ago | "Cambrian Explosion": Rapid diversification of multicellular life in oceans. |
| - | Ordovician | 485 million years ago | First vertebrates and colonization of land by plants. |
| - | Silurian | 444 million years ago | First land plants and arthropods appear. |
| - | Devonian | 419 million years ago | "Age of Fishes": Diversification of fish; first amphibians and trees. |
| - | Carboniferous | 359 million years ago | Extensive forests form; first reptiles and winged insects evolve. |
| - | Permian | 299 million years ago | Pangaea supercontinent forms; ends with the largest mass extinction in Earth's history. |
| Mesozoic | Triassic | 252 million years ago | Early dinosaurs and mammals emerge after the Permian extinction. |
| - | Jurassic | 201 million years ago | Dinosaurs dominate the land; first birds evolve. |
| - | Cretaceous | 145 million years ago | Flowering plants appear; ends with the extinction of non-avian dinosaurs. |
| Cenozoic | Paleogene | 66 million years ago | Mammals diversify and become the dominant land animals. |
| - | Neogene | 23 million years ago | Early hominins appear in Africa; grasslands spread globally. |
| - | Quaternary | 2.6 million years ago | Ice ages occur; modern humans evolve. |
| - | Holocene | 11,700 years ago | Human civilization develops; agriculture, cities, and technology shape the world. |
Notable Biological Evolution
| Era | Date | Event |
|---|---|---|
| Mesozoic | 150 million years ago | First birds, like Archaeopteryx, evolve from theropod dinosaurs. |
Conclusion
The timeline of Earth reflects a dynamic history of geological transformations and evolutionary milestones, from the formation of the planet to the rise of complex life forms.