In the context of a presentation on mathematical models for antibiotic-resistance bacteria research, someone mentioned that wild type strain (WT) are expected to be more fit than mutant strains.
Assume that there is one WT introduced to an environment E (no drugs present), and consider the WT mutates, yielding a certain number of fit-enough mutant strains.
Is WT expected to be the ONLY strain to persist in the long run?
How common is this scenario?
What about co-existence?
Examples and references for beginners will be very appreciated.
My context: Please note that this may be a very naive question, and I may even be using the wrong terminology, given my background on mathematical modeling and a very, very basic knowledge on evolution.
Thinking about dynamical systems, I would have guessed that coexistence would be possible, so I didn't understand how strong was such an assumption.