Precambrian era

Okay, so a long long time ago, before even dinosaurs existed, there was a time called the Precambrian Era. It started about 4.6 billion years ago and ended about 540 million years ago. That's a really really long time, like way longer than you can even imagine!

During the Precambrian Era, the Earth was just getting started and still forming. There weren't even any plants or animals yet! The Earth was like a big ball of hot molten rocks and it was slowly cooling down.

After a while, some simple single-celled organisms started to form in the water. These were like very small and basic forms of life, kind of like tiny bacteria. They didn't look like any animals or plants we know today, but they were alive and moving around!

Over millions of years, these simple life forms evolved into more complex ones, like jellyfish and sponges. Eventually, around 540 million years ago, the Precambrian Era ended and the Cambrian Era began. This is when we start seeing the first fossils of animals with hard shells and body parts like trilobites and strange creatures like the Hallucigenia.

So, to sum up, the Precambrian Era was a really long time ago when the Earth was just getting started and there were only simple life forms like bacteria and jellyfish.