Joni Mitchell was right when she sang "We are stardust ..." in her song "Woodstock." According to University of Chicago professor Neil Shubin in his recent book The Universe Within: Discovering the Common History of Rocks, Planets, and People, the human body is composed of elements that were forged by the stars. There had been a point when there was only hydrogen, helium, and lithium. The process took billions of years, and it may have been only five to ten million years ago that the right elements in the right quantities under the right conditions allowed our species, or at least its predecessors, to evolve on earth. No knowing about elsewhere.
So what contributed to our appearance on earth? Our solar system had to absorb stellar matter, form spheres, and establish orbits, and the earth had to stabilize with a temperature in a receptive range for life. We need to thank Jupiter and its gravitational pull for keeping us viable. Warm water had to foster the growth of single cell organisms, some of which had to develop photosynthesis to build up available oxygen reserves for a great variety of spiny and spineless creatures to evolve and spread over the planet. There were many other contributing factors. Even the break up of the super continent was necessary to get the balance of elements right.
Shubin has written popular science before. His Your Inner Fish was awarded best book of the year by the National Academy of the Sciences in 2009. The Universe Within expands on the themes he introduced in that book, starting with the Big Bang and ending with the age of DNA research. He tells a great story with many interesting characters, some of them human. Look for it in libraries with the earth sciences books.
Shubin, Neil. The Universe Within: Discovering the Common History of Rocks, Planets, and People. Pantheon Books, 2013. 225p. ISBN 9780307378439.