Only a small fraction of the total life ever on the planet remains

Life on Earth has been constantly changing, evolving as the surface of the planet changes. The land and the life it harbors have evolved together over time. Just as the shape and position of continents and oceans has changed, so has the composition and diversity of the species that inhabit them.

It is estimated that currently are living about 1% (or less) of the total species that have ever existed on the planet. And what happened to the remaining 99%? They have simply become extinct; some in individual events, as failed experiments of evolution, others during periods of mass extinction where many forms of life disappeared.

So far, about 1.5 million species of animals and plants have been counted, even though the estimates indicate that there may be about 8.7 million. Why is it that they are not all known? The determination of the species corresponds to specialists called taxonomists (people who practice Taxonomy, the science of describing and naming species). And these specialists are few and generally located in research centers far away from the places that deserve more attention.

More than half of the species that have been named come from the temperate regions of the American and European continents, which have been studied for a longer time, and which have less diverse ecosystems when compared with, for example, the tropical zone.

Some groups of organisms are better known than others. Among vertebrates, the best known are mammals, birds, crocodiles and turtles. Inventories for other kinds of vertebrates are still far from complete.


Sea turtles are a very small group of relatively well-known species. Photograph by Ralph Pace

Even in well-studied groups, such as birds, the application of new technologies, such as DNA analysis, has made it possible to identify more species. This is the case of the blue finch of Gran Canaria (Fringilla polatzeki) that was believed to be a form similar to the blue finch of Tenerife (Fringilla teydea), but that the genetic analysis revealed it was a totally different species. The destruction of its native forest habitat as well as the indiscriminate collection of specimens has placed the species on the verge of extinction.

The blue finch of Gran Canaria was formally recognized as a full species in 2016. It is one of the most threatened birds in Europe. Photograph by José Manuel González Salas

Extinction of species (or even whole groups, as in frogs) represents additional pressure for ecosystems. Many organisms are disappearing without even having received a scientific name, or have been known. And it is precisely that 1% of known species, which we know are suffering the disappearance of their populations, mainly because of the action of man over nature.

Do you know which species in your surroundings are threatened with extinction?

If you want to know more about the blue finch of Gran Canaria: Fringilla polatzeki

Do you want to know more? 86% of the species on Earth are still unknown