Evolution can't explain photosynthesis (Talk.Origins)

Claim CB510:

Evolution cannot explain the origin of photosynthesis.

Source:
 * Nelson, Chuck, 2001. Purposelessness personified.

CreationWiki response:

This is Talk Origins’ response to any claim that Evolution is incapable of doing something, on the assumption that all they need to do is invent a just so story about how it could happen to show that it is possible. This ignores the fact that any good science fiction writer can make an impossible event sound plausible. Such an argument ignores the fact that the burden of proof is on them to show that such structures can form by natural processes, but they can offer none.

In the case of photosynthesis, the process is an example of Organized complexity, which Statistical Thermodynamics shows cannot form by natural processes.

Translation: They don’t even have enough evidence on which to base even a just so story.

This raises an important question: Is there anything that Talk Origins or any Evolutionist would agree is impossible for evolution to produce, such that if it is actually discovered it would totally falsify the General Theory of Evolution? If not, General Evolution Theory is untestable and therefore unscientific.