First Life on Earth

"While some evidence suggests that life may have originated from non-life in hydrothermal vents on the ocean floor, it is possible that abiogenesis [life arising from non-life] occurred elsewhere, such as deep below Earth’s surface, where newly arisen protocells could have subsisted on methane or hydrogen, or even on ocean shores, where proteinoids may have emerged from the reaction of amino acids with heat and then entered the water as cell-like protein droplets...

As the Miller-Urey experiment demonstrated, organic molecules can form from abiogenic materials under the constraints of Earth’s prebiotic atmosphere. Since the 1950s, researchers have found that amino acids can spontaneously form peptides (small proteins) and that key intermediates in the synthesis of RNA nucleotides (nitrogen-containing compounds [bases] linked to sugar and phosphate groups) can form from prebiotic starting materials... ... in addition to carrying and translating genetic information, RNA is a catalyst, a molecule that increases the rate of a reaction without itself being consumed, meaning that a single RNA catalyst could have produced multiple living forms, which would have been advantageous during the rise of life on Earth...  

Stromatolites, deposits formed by the growth of blue-green algae, are the world’s oldest fossils, dating to 3.5 billion years ago."