> Quantum states are highly fragile — sneeze and they disappear in a puff of smoke.
No, quantum states never disappear. They just evolve in time. However, it is hard to isolate a system that you are assigning a state vector from its surroundings.
> They say the processes behind light harvesting are a special blend of the quantum and the classical.
This kind of misleadingly suggests that reality has separate quantum and classical components. That's not the case; everything is quantum. It's just that some things that occur cannot be described accurately with classical physics.
> Because energy can exist in a superposition of states, it can travel a variety of routes around the network at the same time. And when it finds the correct destination, the superposition collapses, leaving the energy at the reaction centre.
Light travels. Energy is just a number that's conserved in non-relativistic QM. Also, while I suppose you could describe light as traveling through every path at once (and I know a lot of physicists like to describe it this way too), it sounds much more mysterious than it needs to be to me. I would just say: "as the wavefunction evolves in time, its probability amplitude spreads throughout space".
> Another is the quantum zeno effect, the paradoxical phenomenon in which an unstable state never changes if it is watched continuously.
This makes it sound like its conscious or something. There's no paradox here. "Watching" is just a series of measurements. Measurements collapse a state into an eigenstate. If you perform these frequently enough, the system doesn't have time to decohere, so it just keeps collapsing into the same eigenstate. It would be less like watching the pot and more like pulling it off the stove each time its about to boil.
Anyway, I sound nitpicky, but I remember that before I learned QM I was always bothered by the fact that people tried to make it sound mysterious and vague for some reason when its actually quite objective and concrete.