against autotroph

I'll change my question about the autotroph vs. heterotroph thing, can you prove that heterotrophs came first than autotrophs?

I think is better to say that there are strong signs that heterotrophy preceded autotrophy.
The earliest Earth was rich in organic compounds from meteorites and comets bombardment.
The earliest atmosphere had no, or very little, oxygen. The organic compounds were not oxidized. Metabolism could not be aerobic.
The molecular studies with archea and bacteria, seem to allocate heterotrophic as the oldest.
Fossils of apparently heterotrophic prokaryotes, precede in 300 MY the oldest known stromatolyte fossils: 3.8 to 3.5 billions years respectively.I think these are correct, but sure there are more.

Thanks for the reply. Though I don't know how to rebut it, which is my main purpose because i'm really defending autotrophism.
I can just say that "how can you be sure that there are no more evidence and there is a possibility that there are more fossils not yet found that can prove my statement?"Again thank you for the info. the other team need not know these proofs....hehe