"In some sense, we're all parasites on plants, that in turn feed on the energy delivered by the giant fusion reactor in the middle of our solar system."
I think that's wrong. By definition, a parasite interacts with a living organism. For example worms that eat the remnants of fallen leafs are not parasites, they are saprophytes. Humans as well can live consuming bits of fallen fruits that do not take part in plants' further reproduction (i.e. fruit's seeds) and would otherwise just rot (and can thus be considered dead tissue).
I think that's wrong. By definition, a parasite interacts with a living organism. For example worms that eat the remnants of fallen leafs are not parasites, they are saprophytes. Humans as well can live consuming bits of fallen fruits that do not take part in plants' further reproduction (i.e. fruit's seeds) and would otherwise just rot (and can thus be considered dead tissue).