The estimates concerning the number of species Over the last centuries the species of man has identified, classified and given a name to about 1.4 million species of living organisms, ranging from bacteria to blue whales. Scientific estimations, until about 10 years ago, placed the total number to be about 5 million. Today, based upon samplings done in the South American rain forests and other locations that sustain a high degree of diversity this number has been substantially re-estimated to be 30 million or more. This endemism, or narrowness of range, makes them extremely vulnerable. Speciation is something that occurs over millions of years Species do not arise overnight.
Evolutionary processes involve millions of years of genetic selection.
A species maintains its uniqueness through its sexual and genetic isolating mechanisms. A species becomes more and more specialised through its struggle to optimise its reproductive chances. The position of the world's biodiversity was a major agenda point at United Nations conference that recently took place in Rio de Janeiro. Biodiversity is the term used to describe the great variety of life forms found upon earth. Because of factors introduced by the presence of man, such as climatic changes and the destruction of the world's rain forests, a mass extinction is now occurring which poses a grave threat to the continuance of much of the life on earth.