Blame people like Boy Hovind for the incomprehensibility of that argument, as it is one of the creationists' classic rectal extractions.
Individuals do not evolve. Population groups do. It is not a quick "morph" like in the cartoons, but a process that encompasses untold numbers of generations.
Your highly primitive species of bacterium evolved into a slightly-less primitive form, which evolved further, and so on. The event [unknown to me] that caused some unicellular organisms to cluster, gave rise to functional specialization of sub-groups within the cluster, and those individual cells lost their independent viability. Soon (after millions of generations, perhaps), these clusters of cells were pressured into reproducing in tandem, and then as a unit, to preserve their viability.
When mobility became a requisite for survival, techniques to move developed...first by flowing within the skin, then by flagella, and millions of evolutions down the road, by the skeletomuscular leverage with which we, as vertebrates, are familiar.
With all this happening, please keep in mind that for every single positive evolution there were scores, hundreds, or even thousands of failures.
Now, I'm not even a biology student, but I believe this covers some of the basic concepts.
Read a book. If it gives you a headache, rest your eyes periodically and take an aspirin.