Definition of Biodiversity

What Is Biodiversity?

Biodiversity refers to the essential variety on our planet, including all organisms and species and their individual genetic variations and how they assemble themselves into harmonized biomes and ecosystems. The concept of biodiversity refers to the rich interconnection and interdependent forces at work in ecosystems that contain creatures of all shapes, sizes, and varieties. There are millions and millions of distinct biological species on the planet that have developed and evolved to depend on a vibrant, varied, biologically diverse system for survival.

Scientists have identified and named over 1.7 million species to date, with millions more yet to be discovered, including 950,000 species of insects, 270,000 species of plants, 19,000 species of fish, 10,500 species of reptiles and amphibians, 9,000 species of birds, and 4,000 species of mammals.[1] These scientists use three separate levels to describe biodiversity, each of which are essential to a healthy biodiversity:

  • Genetic diversity
  • Species diversity
  • Ecosystem diversity

Each of the levels (stated above) impacts the other two levels in significant ways, a process known as the ripple effect. To give you an idea of how these interconnections work, consider these examples:

  • A long-billed bird will pollinate a flower – the bird gains food and the flower gains a reproductive advantage
  • Some insect parasites will live on a particular species of wasp that then lays its eggs on a particular caterpillar
  • Certain bird species will evolve to live in only one small community and cannot be transported to another

Because species are so closely related to one another, when we lose one, there is always the risk that we lose another. Conservation International estimates that we lose one species every 20 minutes, and predicts that 25% of all species will face extinction by 2050 (though some put that figure at 50%).[2] That means between 10,000 and 100,000 species go extinct every year! Current calculations suggest the following percentages for each threatened species:[3]

  • 12% of all birds
  • 21% of all mammals
  • 28% of all reptiles
  • 30% of all amphibians
  • 35% of invertebrates
  • 37% of freshwater fish
  • 70% of plants

The main causes of biodiversity loss include:

  • Habitat loss and destruction due to the expansion of human settlements and agriculture
  • Alterations in ecosystem composition
  • Invasion of alien or non-native species of plants and animals
  • Over exploitation and human consumption of natural resources
  • Pollution and contamination of ecosystems
  • Climate change

The human population will certainly feel a loss of biodiversity in a number of significant ways. Diminishing biodiversity results in:

  • Less food as fish, bird, animal, and plant species decline
  • Loss of livelihood as natural systems are degraded and wiped out
  • Supply falling short of demand resulting in skyrocketing prices for basic necessities
  • Reduction in water quality as ecosystems lose the ability to filter and clean water


1. Diversity of Life. (n.d.). Retrieved November 16, 2010, from WWF Biodiversity911:

2. How do we set our clock?(n.d.). Retrieved November 16, 2010, from Conservation International:

3. What is Biodiversity. (n.d.). Retrieved November 16, 2010, from UN Environment Programme:
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