Answers to frequently asked questions about biodiversity:
What is biodiversity?
Biodiversity is the diversity of genes, species and ecosystems in a region or worldwide.
Why is it important?
Biodiversity, including the existence of countless varieties of small and microscopic organisms that we cannot see or whose appearance we might not like, is essential for supporting life, including that of humans. For example, birds along with bees and other insects are estimated to be responsible for a third of the world's crop pollination, and a wide variety of invertebrates and microorganisms help maintain the productivity of the soil. Likewise, complex webs of organisms in the oceans and other water bodies are necessary to sustain the seafood that provides many millions of people with their main source of protein.
Numerous medicines, along with many other complex chemicals, originate from plants and animals. For example, nearly 25 percent of the pharmaceuticals used in modern medicine are obtained from tropical plants, and the majority of cancer drugs are natural or synthetic products derived from or inspired by living organisms. Thus, every time another species becomes extinct, the opportunity for discovery of a new medicine or other useful substance is lost forever.
How many species are there?
The total number of species currently alive is unknown, and estimates vary widely. Some recent estimates place it at more than eight million, of which only about 14 percent have been described. The great majority of these are microorganisms, such as bacteria and fungi. For example, there are more than 43,000 cataloged species of fungi, and estimates of the total number range from a mere 660,000 to as high as 5.1 million. Likewise, a single spoonful of soil might contain more than 10,000 species of bacteria, many of which have not yet been described, and each human body is home to hundreds or thousands of species of microbes. Moreover, all of these estimates are for currently extant species and thus they are only a tiny fraction of all species that have ever existed.
Species have always been going extinct and they have been replaced by new ones, so what is the problem?
The problem is that the rate of extinction now is far faster than the natural rate of past centuries and millennia, and it can take millions of years for new species to arise.
What is the cause of this accelerating extinction?
It is the result of human activity. This includes deforestation and other forms of habitat destruction, human-caused climate change, hunting and poaching, overfishing, and pollution of the water, land and air.
But is it really a problem? There are many millions of species, so what does it matter if we lose just a few?
One reason is that there is extensive interdependence among species so that the loss of one species often endangers other species. It also matters because every time another species becomes extinct, the opportunity for discovery of a new medicine or other useful substance is lost forever. And very often we are losing some of the most important species, that is, the species that play a major role in maintaining ecosystems. Moreover, we are not losing just a few species, but we are probably losing thousands of species every year and the number of endangered species is increasingly rapidly.
Can anything be done to stop this great loss of biodiversity?
We generally cannot bring back what has already been lost. However, it is definitely possible to slow down the current surge of extinctions. One important way in which this could be accomplished is by stopping the rampant destruction of habitats and restoring damaged habitats, through such means as replanting forests, removing fill and contaminants from degraded or destroyed wetlands, removing harmful alien species, and rewilding.
Another important way is drastically reducing the use of fossil fuels and petrochemicals in order to both stabilize the climate and reduce pollution. Still additional things that could be done include improving land use patterns (such as discouraging sprawl) and reducing the extraordinarily high growth rates of human population that are still common in some parts of the world.