Most of the ways in which animals are useful to us are pretty obvious, whether it's getting milk or cheese from cows, or bacon from pigs - and, of course, many people don't agree that we should kill animals for food. But there are many other benefits we take from the natural world, not least a huge number of life-saving drugs, and as species disappear from the world we are undoubtedly losing still more chances to discover valuable new treatments. Below are just a few examples of the ways in which we have benefited from the biodiversity of the natural world.
Even dangerous plants and animals can have life saving secrets.
The deadly foxglove flower gives us a drug to treat heart conditions, even more bizarrely, a particular type of scorpion venom is crucial in a new therapy for an otherwise untreatable from of brain cancer. A slightly .modified, radioactive form of the venom attaches itself to and destroys only cancer cells, leaving the body's healthy cells almost completely unaffected - a neat and very useful trick, because cancer cells are so similar to healthy ones, and anything that damages cancer cells usually damages other body tissues.