Species on Earth

Emperor penguin (Aptenodytes forsteri), species of bird of Antarctica. Source

How many species exist on Earth? 

Identifying all living beings might seem like an easy task, but it is very complicated due to the great diversity of organisms that are generally unknown and of very small size. If we add the microbes, we would face a challenge of enormous proportions.

Currently, almost 1 million 750 thousand species are known. This is only an approximation very far from the estimated total of 8.7 million. Previous estimates, always surrounded by much controversy, vary between 3 and 100 million species.

A 2016 study predicts that Earth is home to one trillion (1012) of species, many of which would be marine microbes. Of this total of species, only a small fraction, estimated at much less than 1%, would have been described.

Known number of animals and plants in different categories (Excludes the largest group, insects, with about 1 million species). Source

Why is it difficult to know the total number of species on the planet?

It is practically impossible to know the total number of different life forms on the planet, mainly because the pace of discoveries is not enough to carry it out, and because there are not enough taxonomists.

Taxonomists are the people responsible for describing and giving names to species, a task that began in 1735, with the pioneering work of Carl Linnaeus who developed the classification system that is used up to this day. Linnaeus described some 6000 species from all continents, much smaller than the number of new species currently described each year.

The panorama of determining the totality of species on the planet is very complicated for different reasons, among others:

  • A large number of species live in countries with high diversity but incomplete inventories.
  • Little known environments remain, such as tropical forests and oceans.
  • Many species annually disappear without being known.
  • Changes in species nomenclature due to new research and taxonomic revisions.

Why it will it be useful to know the total biodiversity?

  • If we know an organism, we can empathize with it and, therefore, the greater will be our interest in wanting to conserve it if it is threatened.
  • It would facilitate environmental impact assessments, as well as estimates for habitat destruction, climate change and other adverse effects resulting from human activity.
  • Greater knowledge of biodiversity would encourage conservation studies and ecotouris

Which countries do you think have the greatest diversity of species? Which ones would you like to know?