Biodiversity

Biodiversity is valuable for the following classes of reasons:

1. Intrinsic Value. Biodiversity has its own intrinsic value, regardless of its worth in terms of human needs. Because of its intrinsic merit, there are ethical considerations to any degradation of biodiversity. For example, do humans have the "right" to diminish or exterminate elements of biodiversity, all of which are unique and irretrievable? Is the human existence itself diminished by losses of biodiversity? Ethical issues cannot be resolved through science, but enlightened people would mourn any loss of species, or of natural ecosystems.
2. Utilitarian Value. Humans have an absolute requirement for the products of other species. Because of this need, wild and domesticated species and their communities are exploited in many ways to provide food, materials, energy, and other goods and services. This fact can be illustrated in many ways. In the United States, for example, about one-quarter of prescription drugs have active ingredients obtained from higher plants, and these uses contribute about $14 billion per year to the U.S. economy, and $40 billion per year worldwide. Potentially, harvests of biodiversity can be conducted in ways that foster their renewal. Unfortunately, potentially renewable biodiversity resources are often harvested too intensively or inadequate attention is paid to regeneration, so the resource is degraded or becomes extinct.
3. Provision of Ecological Services. Biodiversity provides many ecological services that are directly or indirectly important to human welfare. Examples of these services include biological productivity, nutrient cycling, cleaning water and air of pollutants, control of erosion, provision of atmospheric oxygen, removal of carbon dioxide, and other functions related to the integrity of ecosystems. According to the biologist Peter Raven: "Biodiversity keeps the planet habitable and ecosystems functional."

There are many cases of the discovery, through research on previously unexploited plants and animals, of bio-products useful to humans as food, medicine, or for other purposes. Consider the case of the rosy periwinkle (Catharantus roseus), a small plant native to the tropical island of Madagascar. During an extensive screening of wild plants for anti-cancer chemicals, an extract of rosy periwinkle was observed to inhibit the growth of cancerous cells. The active biochemicals are several alkaloids in foliage of the plant, which probably serve to deter herbivores. These natural substances are now used to prepare the drugs vincristine and vinblastine, which can be successfully used to treat childhood leukemia and a lymphatic cancer known as Hodgkin's disease. In this case, a species of wild plant known only to a few botanists has proven to be of great benefit to humans by treating previously incurable diseases, in the process sustaining a large pharmaceutical economy. There is a tremendous undiscovered wealth of other biological products useful to humans in unexplored biodiversity.