ICANT writes:
I understand the statement to mean more than one as they are to be spread out on a plate.
It nowhere says all these bacteria was from a single bacteria.
You are correct. The Lederbergs' experiment does not show the source of the mutation. It only shows that the observed mutations were not induced by the antibiotic or after the antibiotic was introduced. The limitations of the experiment are no surprise; they are appropriate for the hypothesis being tested.
That seems to be of little consequence in light of other more detailed experiments. Other experiments have been done showing mutations of bacteria genome over a large number of generations.
One such experiment is described
here:
Molecular methods are used widely to measure genetic diversity within populations and determine relationships among species. However, it is difficult to observe genomic evolution in action because these dynamics are too slow in most organisms. To overcome this limitation, we sampled genomes from populations of Escherichia coli evolving in the laboratory for 10,000 generations. We analyzed the genomes for restriction fragment length polymorphisms (RFLP) using seven insertion sequences (IS) as probes; most polymorphisms detected by this approach reflect rearrangements (including transpositions) rather than point mutations. The evolving genomes became increasingly different from their ancestor over time. Moreover, tremendous diversity accumulated within each population, such that almost every individual had a different genetic fingerprint after 10,000 generations.
The reference linked to above describes several experiments where changes to the genomes of organisms over 100s to thousand of generations where detected. I don't see how any of the results are compatible with your theory that changes were already present in the original organisms.
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