Mutations are by chance.
Darwin taught that the nature would select those mutations of chance that are beneficial.
Thus he taught that life developed from by chance mutations.
"In a letter to Joseph Dalton Hooker on February 1, 1871, Charles Darwin made the suggestion that the original spark of life may have begun in a “warm little pond, with all sorts of ammonia and phosphoric salts, lights, heat, electricity, etc. present, so that a protein compound was chemically formed ready to undergo still more complex changes”.
Note the blind acceptance that life began without intelligent design.
One of the leading proponents of life beginning on its own from non-living sources, or abiogenesis, is Carl R. Woese. Note what he writes on this site.
"Biologists have long subscribed to the powerful, unifying idea that all life on Earth arose from a common ancestor"
Blind acceptance of Darwinism in other words.
From that theory, which is full of holes, as any impartial observer can see, he writes.
“Nothing concrete could be said about the nature of this ancestor initially, but it was intuitively assumed to be simple, often likened to a prokaryote, and generally held to have had little or no intermediary metabolism . Only when biology could be defined on the level of molecular sequences would it become possible to seriously question the nature of this ancestor.”
Note how he now goes from a very weak theory of evolution, supported and pushed and forced on people, only because it claims to explain life developing without God, to blindly accepting as fact that life developed from non-living sources.
Thus he goes from an extremely weak theory, which is only popular BECAUSE it can explain life developing without supernatural means, to the assumption that it HAD TO HAPPEN.
Note that there is NO evidence for such an ancestor to have ever existed. None.
Notice what he writes next.
"The unrooted universal phylogenetic tree that emerged from ribosomal RNA (rRNA) sequence comparisons provided the first glimpse of our ultimate ancestor, albeit an indirect one (3, 4). Whatever it was, this cryptic entity had spawned three remarkably different primary groupings of organisms (domains)http://www.pnas.org/math/12pt/normal/mdash.gifthe Archaea, the Bacteria, and the Eucarya-and these necessarily reflected the ancestor’s nature. Phylogenies derived from the few other molecules that then had been sequenced confirmed the three predicted groupings, and concurrent biochemical characterizations further developed their uniqueness But, from this first universal tree, one could infer only that the ancestor was some ill-defined “urstoff” from which three primary lines of descent somehow arose . "
He just assumes this ancestor existed. Since he assumes it had to exist, then he assumes it had to develop from “molecular sequences” which could replicate. Of course these phantom “molecular sequences” that replicate have never been found, nor the ancestor similar to a prokaryote.
Why does he assume they had to exist. Because he blindly believes in evolution by chance mutations and natural selection.
Note that none of his early life assumptions are based on any factual data, but solely on preconceived theories.
It is all based on a weak theory, and blindly accepted as true and factual and a tremendous amount of stories and myths are built up to fill in the vast amount of missing data to make the theory even remotely plausible.
He doesn’t even begin to explain how one of the simplest parts, which is a cell wall, could develop from non-living sources. Cell walls are not inert, like a plastic film. They are living entities, which must take in oxygen, and selective nutrients, excrete wastes, CO2, etc. He doesn’t even begin to explain what would make RNA to even think of forming a cell wall or how in the world chance mutations of RNA would occur that could even form a cell wall.