A lifetime of life on earth?

Life on Earth has a long and complex history that spans over 4 billion years. Here is a brief timeline of some of the key events in the evolution of life on our planet:

• 4 billion years ago: The Earth formed from a cloud of dust and gas around the sun.

• 3.8 billion years ago: The first evidence of life appears in the form of fossilised microbial mats.

• 1 billion years ago: Complex, multicellular organisms begin to appear.

• 540 million years ago: The Cambrian explosion occurred, resulting in a rapid diversification of life on Earth.

• 252 million years ago: The Permian-Triassic extinction event, also known as the "Great Dying," wipes out over 95% of all species on Earth.

• 66 million years ago: The Cretaceous-Paleogene extinction event, also known as the K-T event, caused the extinction of the dinosaurs and many other species.

• 2.5 million years ago: The first hominids, or human ancestors, appear in Africa.

• 200,000 years ago: Homo sapiens, or modern humans, evolved in Africa.

• 12,000 years ago: The development of agriculture marks the beginning of the Holocene epoch and the end of the last glacial period.

This timeline only scratches the surface of the incredible diversity and complexity of life on Earth. There have been countless other events, extinctions, and evolutionary innovations that have shaped the history of life on our planet.