How Many Species Are There on Earth?

There are thought to be about 9 million different species on Earth, not counting bacteria. Out of all these species, almost 85 percent on land and about 90 percent of those in the water have yet to be discovered or described. Out of the five kingdoms of species counted in the estimate, Animalia has the most species, with more than 7.8 million species projected. The smallest kingdom is Chromista, which includes algae and other basic cells, with only about 100,000 projected species. Of these, less than half have been cataloged.

More facts about species:

• If bacteria were counted in the number of species on Earth, it would be dramatically higher. Although estimates of the number of species of bacteria vary widely, even the most conservative are in the 10 million range. That would mean that the number of species on Earth would more than double.


• There are more than 611,000 species of fungi alone, fewer than 15 percent of which have been described and cataloged.


• If the 9 million species estimate is correct, even the most sophisticated endangered species list reviews only about 1 percent of all species.

Frequently Asked Questions

How many species are currently identified on Earth?

As of the latest estimates, scientists have identified over 1.7 million species on Earth. This number includes animals, plants, fungi, and microorganisms. However, this is believed to be just a fraction of the total number of species, with many more awaiting discovery, particularly in biodiversity hotspots like rainforests and coral reefs.

What is the estimated total number of species on Earth?

While only about 1.7 million species have been formally described, estimates of the total number of species on Earth vary widely. According to recent scientific studies, the Earth could be home to anywhere from 8.7 million to over 1 trillion species, accounting for all the microorganisms that are yet to be discovered.

Why is it difficult to determine the exact number of species on Earth?

Determining the exact number of species is challenging due to several factors. Many regions of the world, such as deep oceans and dense rainforests, are underexplored. Additionally, many species, especially smaller organisms and microorganisms, are difficult to detect and identify. The ongoing loss of habitats and species extinction also complicates the count.

Which group of organisms has the most identified species?

Insects are the group with the most identified species, representing a significant portion of biodiversity. According to scientific records, there are over 950,000 known species of insects, which is more than half of all known living organisms. This reflects their adaptability and evolutionary success across various ecosystems.

How are new species discovered and documented?

New species are discovered through field expeditions, the study of museum collections, and advances in technology such as DNA analysis. Scientists often venture into unexplored or underexplored habitats to collect specimens, which are then analyzed morphologically and genetically to determine if they represent new species.

What is the importance of knowing the number of species on Earth?

Understanding the number of species on Earth is crucial for biodiversity conservation. It helps scientists assess the health of ecosystems, guide conservation priorities, and measure the impacts of human activities on the environment. Knowing species diversity also aids in the discovery of new resources, such as medicines, and in understanding the intricacies of ecological interactions.