Key Facts on Biodiversity

• Though the exact number is impossible to determine, an unprecedented mass extinction of life on Earth is occurring. Scientists estimate that between 150 and 200 species of life become extinct every 24 hours.
  
  
• There have always been periods of extinction in the planet's history, but this episode of species extinction is greater than anything the world has experienced for the past 65 million years-the greatest rate of extinction since the vanishing of the dinosaurs.
  
  
• Some 60 per cent of the plant species endemic to the Galapagos Islands are threatened with extinction, as are 75 per cent of the endemic plant species of the Canary Islands. If we continue with our unsustainable patterns of activity, one-fifth of all species could become extinct in the next two decades.
  
  
• This mass extinction is due, in large measure, to humankind's unsustainable methods of production and consumption. This mass extinction is due, in large measure, to humankind's unsustainable methods of production and consumption.
  
  
• More than 60 per cent of the world's people depend directly on plants for their medicines.
  
  
• About 12 per cent of mammal species and 11 per cent of bird species were classified as threatened in 1990.
  
  
• Nearly every animal species may be host to several specialized parasitic species, only a small fraction of which have been described.
  
  
• According to the World Resources Institute, the biggest cause of extinction is loss of habitat.
  
  
• There are as many as 100 million species on Earth, of which only 1.7 million have been identified.
  
  
• Humans are but one of those species.
  
  

All photos, text and illustrations Copyright ©1996 The United Nations Environment Programme.