We all know that we need to save as much biodiversity as possible because we do not know what a species might be capable of doing. The rare species of tree on which I have done research has turned out to show great promise of producing a pharmaceutical product—a corporation is investigating this possibility.
And it is not just species diversity. It is the diversity of genetic lineages within species. Take the example of Penicillium mold.
We have all heard the story of how Alexander Fleming discovered penicillin. He was trying to find a way to kill pathogenic bacteria. When he came back from vacation (I hope I am getting this right), he found some green Penicillium mold growing in some bacterial plates he had neglected to sterilize. He saw the clear zone around the mold, in which a chemical produced by the mold had killed the bacteria. And, as far as most of us might have known, this was the triumphant discovery of penicillin, which was quickly ramped up to industrial scale production.
But actually Fleming’s work was mostly a failure. Many strains of Penicillium failed to produce penicillin, and none of them produced enough to allow industrial-scale production of the world’s first antibiotic. In 1940, Howard Florey and Ernst Chain tried again. They decided to sample lots of strains of Penicillium, in the hopes of finding one that produced lots of penicillin. They worked in Peoria, and asked for people to bring in specimens of the famous green mold. Most of them were fairly worthless. But someone in Peoria brought in a cantaloupe that just happened to have a potent strain of Penicillium. That is where the industrial production of penicillin got started.
It is obvious that, were Penicillium to have become extinct, we would never have found penicillin, and perhaps it would have been a long time before anyone would have thought to look for other antibiotics such as streptomycin. Certainly nobody would have deliberately looked in the soil of Easter Island (Rapa Nui) for microbes that produce (?) rapamycin. But apparently it was also important that this particular strain of Penicillium not become extinct. Just saving a random specimen of Penicillium was not enough.
Saving biodiversity is more than just saving species. It is saving genetic strains within species and saving all the microbes that grow on plants and animals.