The bacterial resistance is a perfect example of how the evolution works, though it is much quicker between the bacteria than it is at the bigger and more complicated life forms. Since the modern medicine has started to be used, lot of medications have been used to kill the bacteria in order to prevent or cure diseases among the people. It has been noticed though that the bacteria needs very short period to adjust to the medications so that they are harmless to it, thus developing resistance. This is a nice example of how the bacteria is evolving in order to be able to survive and thrive in a new environment where there's something that destroys it, thus it is developing advantageous traits to be able to survive.
