Unsettling Issues That Remain
Science can take us as far back as a single-celled, complex, organism. We can also show that simple elements can naturally come together to create amino acids. But 100's of amino acids make a single protein and DNA (even the more simple RNA) is far more complex than that. How could early life replicate itself without DNA or RNA? There appears to be an enormous gap.
Where's the link? How did life make this incredible jump from pre-biological chemistry in just a few hundred million years? Must we invoke Divine Intervention? There are other unsolved issues.
Handedness
Amino Acids come in two geometries: Left-handed and Right-handed.
Naturally occurring Amino Acids are equally divided between the two kinds.
So, how come all 20 biologically active Amino Acids are Left-handed?
What's more, sugars and nucleic acids in DNA/RNA are all Right-handed.
Answer: Once life began using Amino Acids, all Amino Acids had to 'match',
the same is true for DNA/RNA. You can't mix handedness. So once a certain
handedness was established (and either one or the other would have been)
it was set to be the mode for that time forward.
Cellular Membranes
A membrane defines what is and is not part of an organism.
It also allows it to isolate nutrients, contain its genetic code,
and dispose of waste outside itself. The cell membrane allows for
the charge separation required for REDOX reactions. Even the simplest
single-celled organism have highly complex cell membranes. How
did such structures come about? How did the earliest life
accomplish such things without a complex cell wall?