The first life on Earth is thought to have appeared around 3.8 billion years ago in the form of simple single-celled organisms. Over the next few billion years, these organisms evolved and diversified into more complex forms. By 500 million years ago, the first animals had appeared in the oceans.
Around 250 million years ago, the Earth experienced a mass extinction event that wiped out most of the life on the planet. This event is believed to have been caused by a massive volcanic eruption that released huge amounts of carbon dioxide into the atmosphere.
Over the next few million years, the Earth recovered and life began to diversify again. Around 65 million years ago, a large asteroid struck the Earth, causing another mass extinction event. This event is believed to have wiped out the dinosaurs and allowed mammals to become the dominant species on the planet.
Since then, the Earth has continued to evolve and change. The climate has fluctuated, species have come and gone, and humans have appeared and spread across the planet. Today, the Earth is home to millions of species, including humans, and is a vibrant and diverse place.