The topic I am undertaking with Earth's development, evolution, and extinction events could take a semester or even a lifetime to study depending on the degree of detail one wishes to examine. For our purposes here, I will be as brief as possible. For topics like this, I usually would avoid Wiki" and go to a more established science platform, but since we are being general in our approach I will offer this link which will give a more detailed view than what I will share, but still be brief enough for basic understanding: (Link to Geologic Time Scale with events)
To begin, let's go back 4600 million years to the formation of the Earth from swirling clouds to a tumultuous rock. Eventually things cooled down and meteor and asteroid bombardments bring water to the planet. And not that long after water is introduced, very early proto-life develops in the form of nucleic acids and eventually simple self-replicating cells. But this takes time......a LOT of time. While evidence points to life as early as 4280 million years ago, it isn't until 4000 million years ago that we see fossil evidence of it. Eventually bacteria develop that produce............OXYGEN!
More complex cells develop with nuclei. And nearly 2000 million years later we see the Earth with an oxygen atmosphere. This is a game-changer and also important in realizing that evolution is not one-sided. Organisms don't merely adapt to a changing geological environment, but contribute to changing that environment by their mere presence. The development of the non-living characteristics of our planet is just as influenced by the presence of life, as life is influenced by the non-living aspects. Things are what they are because of this complex, often chance-orchestrated dance of circumstances.
Once cells become complex and begin to form very primitive multicellular organisms, the jump to more complex organisms seems wondrous. And about 540 million years ago life explodes across the seas in the "Cambrian Explosion" (not a destructive explosion like a bomb, but a very rapid diversification of complex life).