Most of Earth’s 8.7m species remain unknown

PLANET EARTH is home to 8.7 million species of animals and plants, only a tiny proportion of which are known to science.

Scientists adopted a way of estimating species numbers more accurately. Previous estimates have put it at anything from three to 100 million.

The research indicates there are 6.5 million species living on land and 2.2 million, about a quarter of the total, in the oceans.

Yet 86% of all terrestrial species and 91% of marine species have yet to be discovered and catalogued.

Lead scientist Dr Camilo Mora, from the University of Hawaii, US, and Dalhousie University in Halifax, Canada, said: “The question of how many species exist has intrigued scientists for centuries and the answer, coupled with research by others into species’ distribution and abundance, is particularly important now because a host of human activities and influences are accelerating the rate of extinctions.

“Many species may vanish before we even know of their existence, of their unique niche and function in ecosystems, and of their potential contribution to improve human well-being.”

Experts from the Census of Marine Life, a major investigation of life in the oceans, reported their findings in online journal Public Library of Science Biology.

Swedish scientist Carl Linnaeus created the system still used to name and describe species in 1758.

In the 253 years since, around 1.2 million species, roughly a million on land and 250,000 in the oceans, have been described and catalogued.