The Earth became habitable for mankind about 1 billion years ago.
The Earth didn't become habitable for mankind. Mankind evolved to inhabit The Earth.
No. Earth generated a free oxygen atmosphere about 1.7 billion years ago. The atmosphere took another 700 million years to get to the point where mankind could live on the planet. There have been MILLIONS of critters evolve, and die out,long before we came along.
We are merely the latest in a long line of critters to pass through.
And, the planet is still evolving too.