Most bacteria are eventually able to change their genetic makeup in order to become resistant to antibiotics. Therefore, the antibiotics no longer have an effect on the infections.
Sorry, I didn´t see this one, maybe you already have the answer, if not: Yes, it is a good idea, because it balances the impact forces of every bumper car.
It is different because the energy moving through the ecosystem is from organisms, and the energy moving through an ecosystem is from sunlight and other resources.