How did the world start

The earth formed around 4.54 billion years ago, approximately one-third the age of the universe, by accretion from the solar nebula. Volcanic out gassing probably created the primordial atmosphere and then the ocean, but the early atmosphere contained almost no oxygen.

How did life evolve on Earth?

The evolutionary history of life on Earth traces the processes by which living and fossil organisms evolved, from the earliest emergence of life to the present. Earth formed about 4.5 billion years (Ga) ago and evidence suggests life emerged prior to 3.7 Ga.