How many species live on Earth and in the ocean?
A validated taxonomic extrapolation estimates ~8.7 million eukaryotic species on Earth, with most still undescribed.
Source
How many species are there on Earth and in the ocean?
Study at a glance
- Design
- Computational / modelling — Higher-taxon discovery models extrapolating eukaryotic species richness, plus taxonomist survey
- N
- N=548 · 548 taxonomists responded of ~2,938 contacted (18.7%); species estimate ~8.7 million is model-based
- Population
- Global taxonomic catalogues and surveyed taxonomy experts
- Outcome
- Estimated number of eukaryotic species on Earth and in the ocean
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Inspect source passages
How many species live on Earth and in the ocean?
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Estimate of ~8.7 million species on Earth.
Our current estimate of ∼8.7 million species narrows the range of 3 to 100 million species suggested by taxonomic experts and it suggests that after 250 years of taxonomic classification only a small fraction of species on Earth (∼14%) and in the ocean (∼9%) have been indexed in a central database ().
What fraction of Earth species are catalogued?
only a small fraction of species on Earth (∼14%) and in the ocean (∼9%) have been indexed in a central database ().
What they did
Authors modeled higher-taxon discovery patterns to extrapolate species richness for Earth and ocean eukaryotes, validating against well-sampled groups and surveying taxonomists about synonyms and effort.
What they found
They estimate ~8.7 million species overall, narrowing prior expert ranges of 3–100 million, and conclude only ~14% of Earth and ~9% of ocean species are catalogued after 250 years of taxonomy.
The limits
What it doesn't show
Prokaryote diversity is poorly captured by the same species concept; estimates will shift with better synonym control and sampling.
Key terms
- Species richness
- Count of distinct species in a region or on Earth.
- Higher-taxon approach
- Using patterns among known genera/families to extrapolate unknown species.
- Synonymy
- Multiple names for the same species that inflate catalogue counts.
- Taxonomic effort
- Rate and capacity of describing new species.
- Marine biodiversity
- Species diversity in ocean ecosystems.
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Headline Earth species estimate:
Common questions
What is the headline Earth estimate?
About 8.7 million species.
How much is catalogued?
Roughly 14% on Earth and 9% in the ocean.
What prior range did this narrow?
Expert guesses from about 3 to 100 million.
Why are prokaryotes special?
Species concepts differ; known prokaryotes barely move the eukaryotic total.
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