Biological diversity, very simply, refers to all of the different kinds of life on Earth. Also called biodiversity, biological diversity is often used to refer to the total number of different species on Earth. A collection of this biodiversity would include human beings, Bengal tigers, sugar maples, oyster mushrooms, bacteria, and the millions of other living organisms found on Earth. Conservative estimates of the number of species on Earth range from 5 to7 million but some scientists estimate as many as 30 million! With only about 1.6 to 2 million of these species having been studied (many only at the most basic level) and given a name, much still needs to be learned about the diversity of life on Earth.

Much of the Earth's biodiversity is concentrated in the tropics. Some scientists estimate that 50 percent of all species on the planet are found in tropical rainforests that comprise only 6 to 7 percent of the Earth's land surface. Given the rapid rate at which tropical rainforests are being cut, it is estimated that up to 20 percent of the Earth's biodiversity may become extinct in our lifetime! 

Loss of this biodiversity means we would not only lose rich and beautiful ecosystems but we might also lose plants and other organisms that could improve or enrich our lives. Already the tropical forests have provided humankind with food crops we enjoy daily such as tomatoes, peppers, corn, rice, coconut, banana, coffee, cocoa, cassava (tapioca), beans, and sweet potatoes, to name but a few. Tropical biodiversity has also provided us with many medicines used to treat such diseases as malaria. How many more valuable products lie waiting in the tropical forests to be discovered before they disappear?