[on-ramp]

but seriously,

4.5 billion years go (yes, that's a damn long time), earth was formed.

then about 3.5 billion years ago, that's 1 billion years after the earth was formed, came the first life in the form of a prokaryotic cell. these cell bacteria dominated the earth.

then about 1.5 billion years ago, nucleated cells arose, these being of the eukaryotic type. (with nucleus and DNA).

then about .5 billion years ago, there was the cambrian explosion when multicellular eukaryotes arose

fast forward to today. we are the product of billion years of evolution. how fascination..

but why and how? i don't know.