When the solar system settled into its current layout about 4.6 billion years ago, Earth formed when gravity pulled swirling gas and dust in to become the third planet from the Sun.
Banded Iron formations
The first known single-celled organisms appeared on Earth about 4 billion years ago, roughly a billion years after Earth formed.
About 3.5 billion years ago cyanobacteria would form and would eventually using all the silt and debris made stromatolites
KT mass extinction
around 3 billion years ago, photosynthetic organisms were making oxygen, but it reacted with the iron dissolved in seawater to form iron oxide minerals on the ocean floor, creating banded iron formations.
Around 541 million years ago there was a sudden appearance of complex animals.
The KT mass extinction was a global extinction event that happened around 66 million years ago close to the boundary between the cretaceous and paleogene period. It was responsible for wiping out 80% of animals existing at the time.