The physiology of bears could lead to a better understanding of some diseases
A new generation of medical treatments could be lost forever unless the current rate of biodiversity loss is reversed, conservationists have warned.
They say species are being lost before researchers have had the chance to examine and understand their potential health benefits.
The findings appear in Sustaining Life, a book involving more than 100 experts.
It is being published ahead of a global summit in May that will look at ways to stem biodiversity loss by 2010.
"While extinction is alarming in its own right, the book demonstrates that many species can help human lives," said co-author Jeffrey McNeely, chief scientist at IUCN (formerly known as the World Conservation Union).
"If we needed more justification for action to conserve species, it offers dozens of dramatic examples of both why and how citizens can act in ways that will conserve, rather than destroy, the species that enrich our lives."
Killing the cure
One creature whose potential benefits have been lost to science is the southern gastric brooding frog (Rheobatrachus silus), say the authors.
Some sharks have seen numbers fall by as much as 75% in 15 years
First described in 1973, the frogs, which were only found in Australia, interested researchers because they raised their young in the females' stomachs.
Preliminary studies suggested that the young produced substances that stopped them being digested.
Further research could have led to new ways of preventing and treating stomach ulcers in humans, but the amphibian was last recorded in the wild in 1981.
"These studies could not be continued because both species of Rheobactrachus became extinct," said co-authors Eric Chivian and Aaron Bernstein from Harvard Medical School, US.
"The valuable medical secrets they held are now gone forever."
The team added that there was a wide range of threatened species whose biology could hold secrets to possible treatments for a growing variety of ailments.
For example, they said some bears' ability to maintain bone mass when they entered a dormant state could lead to a better understanding of diseases such as osteoporosis.
"We must do something about what is happening to biodiversity," the UN Environment Programme's (Unep) executive director, Achim Steiner, told a conference in Singapore, where the book was previewed.
"Societies depend on nature for treating diseases; health systems over human history have their foundation on animal and planet products that are used for treatment."
The authors hope the publication will illustrate why delegates at a forthcoming key biodiversity summit in Germany have to back plans to halt species loss by 2010.
Mr Steiner said: "The UN Convention on Biological Diversity (CBD) has achieved a great deal but it needs to achieve more if it is to meet the international community's goals and objectives.
"We need a breakthrough in Bonn on all three pillars of the convention: conservation, sustainable use, and access and benefit sharing of genetic resources."