I heard a very good point against evolution

Life is abundant. In simple terms, a mutation that would occur to a bacterium once in the time that life has been on Earth will occur to one of the bacteria in your gut roughly daily. There are 7 billion people on Earth and they compose a tiny fraction of the biomass. Mutations are passed on, and some are transferred between organisms. Additionally, it doesn't take hundreds of thousands of years to evolve slightly. It has been observed in populations of vertebrates in spans of decades or less. Radical changes in bacteria have been seen in the same time span.

1)Single celled organisms can evolve much more rapidly than that. And the assumption that only one started the chain is not necessarily a valid assumption.
2) 20 seperate, individual mutations from a single organism mat take 200,000 years to develop into 20 unique organisms.
#) Along the 200,000 year differentiation, how many other copy errors could occur spawning how many more unique species?
4) You are assuming that no more genetic anomalies can occur until the first has completely evolved.
5) The fossil record indicates the sudden appearance of hundreds if not thousands of new species.
6) Which can also reinforce that god did it in "seven days" as long as you ge tover the concept that those "seven days" were not one week.

You forget that in the beginning there was no ecoli. It was a very very very simple lifeform that made lots of errors while reproducing. We still make much errors.

Todays bacteria have all this systems to keep the genome stable and avoid mutation. Back then this didnt evolve yet.