A biodiversity summit is where scientists and policy-makers meet for talks on what can be done to preserve biodiversity.

Biodiversity is the variety of all life on Earth - including animals, plants, fungi and micro-organisms like bacteria.

Together they provide the planet with everything necessary for survival, including fresh water, clean air, food and medicine. Biodiversity matters because humans cannot get these benefits from individual species - a rich variety of living things must work together in harmony as part of an ecosystem.

Plants, for example, are very important for improving our physical environment: cleaning the air, limiting rising temperatures and providing protection against climate change.

Reverse nature's decline or there is no future - UN

The United Nations' biodiversity chief says global talks under way in Montreal are the "last chance" to reverse the destruction of the natural world.

"Biodiversity is the foundation of life. Without it, there is no life," Elizabeth Maruma Mrema stated.

But she is worried about the amount of work still needed for the 196 countries to reach an agreement.