As John Lennox of Oxford University points out: the theory of evolution presumes the existence of a mutating replicator, but it tells us nothing about how the mutating replicator got there in the first place.
The specific problem involves this: a certain number of highly complex genes must have been present in the very first theoretical living cell in order for it to produce more organisms.
These kinds of logical problems present a very serious challenge to Rand’s ideology, given that her atheism seems to be fundamental to her ideology and these problems describe reality in terms which refute atheistic naturalism.