There are a whole bunch of plants on this planet which produce an array of chemicals. I'm sure there are chemicals in the plants which had developped as a result of natural selection; some of them are used to help the plant survive certain conditions/predators. But I'm sure there are a lot of chemicals which don't seem to have any value to the survival/reproduction of the plant. As far as I know, these chemicals (like aspirin, for example) are more useful to humans/other creatures than to the plant itself. Does each and every chemical a plant produce have a specific function for the plant itself? I have a few thoughts on this.. A friend of mine suggested that these chemicals might not necessarily have use for the plant, but it could have been created as a by product of some other reaction within the plant. This could be true, but, as far as my knowledge in chemistry goes, the chemical reaction would need to involve a chemical that's similar in structure to what is being produced. Morphine, for example, has a specific structure and requires a reactant of a somewhat similar structure to be produced. So it still seems to bring it back to the initial question; the plant would have to produce a morphine related structure, but what would be the purpose of doing this? Another thought I had, assuming certain chemicals don't have a reason in being in the plant, was that these chemicals are produced to help other species survive. This would imply that the plant, in evolving, had intentions of assisting the survival of future species. In some ways I'd like to believe that there is an overall awareness within evolution, an arranged plan. The plants are realllllllly old, AFAIK, one of the first forms of life (well, maybe not that close, but they're earlier than the insects). So the chemicals they had produced through evolution at the time weren't designed to fight off any predators, because there weren't any predators there to eat it. Okay, I must add that I'm speculating here, I really don't know very much about plants; I'm sure there were predators, but surely all plants had more advantage in survival then than they do now. I'm guessing the determing factor at that point was reproduction/surviving the elements...So anyways, these plants made the chemicals many, many years ago and only now do we really see how useful they are for ourselves and most certainly other species. End!