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Evidence record

How many living things have we never met?

Every sentence on the exploration belongs to at least one claim below. Each says what kind of statement it is, what it rests on, what the evidence does not establish, and how far it was checked. Nothing here is a score, and none of it is a verdict on a belief or a theory.

Last checked 19 October 2026.

  • A judgement, not a fact: 15
  • Source checked: 42
  • Partly checked: 5

If something here is wrong, misquoted, out of date or unfair, write to support@unknownoceans.com and give the claim number, which does not change.

What the question takes for granted

A scientific question about a number nobody can count directly. Every answer is an extrapolation, the methods disagree by orders of magnitude, and for microbes what counts as one species is itself a convention.

  • Most species on Earth have not been described

    Established

    Holds for the central figure of every estimate on the page. It fails only at the bottom of the lowest range, 2 million species with 1.5 million named.

  • Life divides into species that can be counted

    Contested

    Workable for animals and plants, where species are defined by conventions the page’s sources share. For bacteria and archaea the unit counted is a sequence cluster, and how finely to cut it changes the total.

  • To meet a species is to describe and name it

    Contested

    The page counts formal descriptions. Many species without a name have been met in another sense: as DNA sequences in environmental samples, or as specimens waiting in collections.

How the question is labelled

Claim: The unnamed majority

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The page’s title. It follows from claims 3 and 9: on the central figure of every estimate, most species are undescribed.

Claim 1 · checked 24 September 2026 · AI-assisted audit

Claim: Unnamed life

Kind
Framing. Signposting. It asserts nothing a source could check.

The question

Claim: Most species on Earth have no name and no description.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    How Many Species Are There on Earth and in the Ocean?abstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Model

    The source reads: our results suggest that some 86% of existing species on Earth and 91% of species in the ocean still await description

  • Supports

    How many species are there on Earth? Progress and problemssecond paragraph

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: This paper has since become the “default” estimate of the number of living species on the plant (8.75 million), even though approximately 80% of those species are hypothetical.

  • Qualifies

    A census-based estimate of Earth's bacterial and archaeal diversityabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in microbes · Observational study: associations, not causes

    The source reads: From this data set, we recovered 739,880 prokaryotic operational taxonomic units

    Unnamed, but recorded as sequences.

  • Qualifies

    Fungal Diversity Revisited: 2.2 to 3.8 Million Speciesabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: and material in collections awaiting study

    Unnamed, but already collected.

What this does not establish

True of every central estimate on the page. At the bottom of the lowest published range, 2 million species with 1.5 million named, most would be named.

Later work looked for

Europe PMC, 2014 on, titles on species on Earth: the 2023 Perspective reports estimates built on DNA running higher, which widens the undescribed share.

Corrected

24 September 2026. Previously: “Most species on Earth have no name, no description, and no record.” Many unnamed species have a record: the 2019 census recovered hundreds of thousands of prokaryotic sequence types, and a fungal review points to undescribed material already in collections.

Claim 3 · checked 24 September 2026 · AI-assisted audit

Claim: About 2.4 million species of animals, plants, fungi and other eukaryotes had been formally described by August 2026.

Kind
Present-day figure. A count, survey or report finding, as the named source gives it.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Catalogue of Life, release COL26.8 XR (26 August 2026): species by domainclassification of release COL26.8 XR, domain Eukaryota

    Cited · Link answered, 19 October 2026 · Read in full, 19 October 2026 · Reference work

    The source reads: "id":"CS5HF","rank":"domain","status":"accepted","count":2440722,"childCount":7,"name":"Eukaryota"

    The release counts 2,440,722 species of eukaryotes. Bacteria, archaea and viruses are listed beside them as separate groups and are not in this figure.

  • Supports

    Catalogue of Life, release COL26.8 XR (26 August 2026): species in the kingdoms of eukaryotesclassification of release COL26.8 XR, kingdoms under Eukaryota

    Cited · Link answered, 19 October 2026 · Read in full, 19 October 2026 · Reference work

    The source reads: "rank":"kingdom","status":"accepted","count":1780634,"childCount":17311,"name":"Animalia" ... "rank":"kingdom","status":"accepted","count":72698,"childCount":15,"name":"Chromista" ... "rank":"kingdom","status":"accepted","count":174018,"childCount":14272,"name":"Fungi" ... "rank":"kingdom","status":"accepted","count":410502,"childCount":31,"name":"Plantae" ... "rank":"kingdom","status":"accepted","count":2870,"childCount":89,"name":"Protozoa"

    The five kingdoms sum to 2,440,722, the count for Eukaryota.

What this does not establish

The count is the Catalogue of Life’s Extended Release, which adds data from other sources to the part verified by taxonomic experts for the Catalogue. It covers eukaryotes only. The release’s counts do not say how many of these species are extinct.

Later work looked for

Release COL26.8 XR is a fixed version and its counts do not change. The Catalogue’s home page moved on to release COL26.9 XR, issued 25 September 2026, on 19 October 2026; the page dates the figure to the release rather than following it.

Corrected

19 October 2026. Previously: “About 2.4 million species have been formally described.” The figure came from the Catalogue of Life home page, which moved to a later release and stopped carrying it. It is now dated to the August 2026 release and cited to that versioned release, where it is the count for eukaryotes alone: bacteria, archaea and viruses are counted separately.

Claim 4 · checked 19 October 2026 · AI-assisted audit

Claim: Estimates of how many exist range from under 10 million to numbers that make the word “species” difficult to apply at all.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    How many species are there on Earth? Progress and problemssummary; first paragraph

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: Projections have ranged from the millions to the trillions. ... estimates have ranged wildly, from 2 million [2] to 3 trillion [3]

  • Supports

    How Many Species Are There on Earth and in the Ocean?Assessment of Possible Limitations, Species definitions

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Model

    The source reads: that prokaryotes add only 0.1% to the total number of known species is not so much a statement about the diversity of prokaryotes as it is a statement about what a species means in this group

Claim 5 · checked 24 September 2026 · AI-assisted audit

Claim: Cataloguing life is a scientific project about 250 years old.

Kind
Historical claim. A statement about the past that historical evidence can test.
Review
Source checked. The cited passage was read, and it says this.

Formal classification of species, dated by the 2011 analysis.

  • Supports

    How Many Species Are There on Earth and in the Ocean?abstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Model

    The source reads: In spite of 250 years of taxonomic classification and over 1.2 million species already catalogued in a central database

Corrected

24 September 2026. Previously: “Cataloguing life is one of the oldest scientific projects.” The cited analysis gives cataloguing 250 years of taxonomic classification; no source on the page ranks it among the oldest scientific projects.

Claim 6 · checked 24 September 2026 · AI-assisted audit

Claim: It is also one of the least finished.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Follows from claims 3 and 9.

Claim 7 · checked 24 September 2026 · AI-assisted audit

Claim: The catalogue is not merely incomplete.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

A lead into claim 9.

Claim 8 · checked 24 September 2026 · AI-assisted audit

Claim: Depending on whose estimate you take and which group you count, it may be missing most of what is out there, or almost all of it.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    How Many Species Are There on Earth and in the Ocean?abstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Model

    The source reads: our results suggest that some 86% of existing species on Earth and 91% of species in the ocean still await description

  • Supports

    How many species are there on Earth? Progress and problemssection on bacteria, after Table 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: Mora and colleagues [4] estimated approximately 10,000 bacterial species (roughly the number of described species). ... Recent studies have estimated a staggering range of species numbers for bacteria, from low millions [6], to hundreds of millions [10], to low trillions [3].

  • Context

    Fungal Diversity Revisited: 2.2 to 3.8 Million Speciesabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: it appears that at best just 8%, and in the worst case scenario just 3%, are named so far

  • Context

    Can We Name Earth's Species Before They Go Extinct?abstract

    Cited · Link answered, 19 October 2026 · Abstract only, 24 September 2026 · Texts · Review of the field

    The source reads: We argue that the number of species on Earth today is 5 ± 3 million, of which 1.5 million are named.

Later work looked for

As claim 3.

Corrected

24 September 2026. Previously: “Depending on which group you count, it may be missing between three quarters and almost all of what is out there.” No source on the page gives three quarters as a lower bound for any group. The figures run from 86 per cent of eukaryotes on the 2011 estimate to more than nine in ten fungi and nearly all bacteria, and the lower total of Costello, May and Stork puts the missing share lower still. The new wording says what the range of estimates carries.

Claim 9 · checked 24 September 2026 · AI-assisted audit

What has actually been counted

Claim: What has actually been counted

Kind
Framing. Signposting. It asserts nothing a source could check.

What has actually been described

Claim: What has actually been described

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: The Catalogue of Life lists about 2.44 million species of eukaryotes in its August 2026 release.

Kind
Present-day figure. A count, survey or report finding, as the named source gives it.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Catalogue of Life, release COL26.8 XR (26 August 2026): species by domainclassification of release COL26.8 XR, domain Eukaryota

    Cited · Link answered, 19 October 2026 · Read in full, 19 October 2026 · Reference work

    The source reads: "id":"CS5HF","rank":"domain","status":"accepted","count":2440722,"childCount":7,"name":"Eukaryota"

    The release counts 2,440,722 species of eukaryotes. Bacteria, archaea and viruses are listed beside them as separate groups and are not in this figure.

  • Context

    Catalogue of Lifehome page, Documentation

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work

    The source reads: The base release is verified by taxonomic experts specifically for COL. The Extended Release includes extra data from other sources

What this does not establish

The count is the Extended Release, part of which comes from other sources and has not been verified by the Catalogue’s own experts.

Later work looked for

Release COL26.8 XR is a fixed version and its counts do not change. The Catalogue’s home page moved on to release COL26.9 XR, issued 25 September 2026, on 19 October 2026; the page dates the figure to the release rather than following it.

Corrected

24 September 2026. Previously: “The Catalogue of Life lists about 2.44 million species in its August 2026 release, and the total is revised upward with every release.” No source read says the total rises with every release.

19 October 2026. Previously: “The Catalogue of Life lists about 2.44 million species in its August 2026 release.” Read against the versioned release, 2,440,722 is its count for eukaryotes. Bacteria, archaea and viruses are counted separately and are not in it.

Claim 12 · checked 19 October 2026 · AI-assisted audit

Claim: The World Register of Marine Species passed 250,000 accepted living marine species in May 2026, and is edited continuously as taxonomy is revised.

Kind
Present-day figure. A count, survey or report finding, as the named source gives it.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    World Register of Marine Specieshome page, news item added 2026-05-18

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work

    The source reads: as of last Wednesday (13 May 2026), there are officially more than 250.000 accepted (extant) marine species documented in the World Register of Marine Species

  • Supports

    World Register of Marine Specieshome page

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work

    The source reads: WoRMS is continuously updating and strives to reflect current published scientific knowledge, without making new taxonomic decisions.

Later work looked for

The live count on the date read was 250,855 accepted marine species.

Claim 13 · checked 24 September 2026 · AI-assisted audit

Claim: New species are described by the thousand every year, and the rate is not slowing.

Kind
Present-day figure. A count, survey or report finding, as the named source gives it.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

Overall, across all groups. Rates differ between groups: fungi have sped up, insects have not. The 2025 analysis stops at 2020 to allow for the lag before new species reach the databases.

Later work looked for

Europe PMC, 2013 on, titles on rates of species description: the 2025 analysis is the most recent across all life and is now cited. A 2026 paper whose title reports declining rates in one megadiverse insect group (title only read) fits the insect caveat.

Corrected

24 September 2026. Previously: “New species are described at a rate of thousands per year, and the rate is not slowing.” The claim now rests on a 2025 analysis of the Catalogue of Life, cited on the page, rather than on the 2011 analysis’s data to 2006 alone.

Claim 14 · checked 24 September 2026 · AI-assisted audit

Claim: A 2025 analysis of the Catalogue of Life found the fastest years all since 2015, with a peak of 17,044 new species in 2020.

Kind
Present-day figure. A count, survey or report finding, as the named source gives it.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

Unique, accepted, living species in the Catalogue, counted by year of description, to 2020. Recent years may still be undercounted while new names reach the database.

Later work looked for

As claim 14.

Corrected

24 September 2026. Previously: “” Added so that “not slowing” carries a current figure and its source.

Claim 15 · checked 24 September 2026 · AI-assisted audit

Claim: Costello, May and Stork report more taxonomists describing species than ever before, their number growing faster than the rate of description itself.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Partly checked. Only part of the source could be read. What was not read is listed.

  • Supports

    Can We Name Earth's Species Before They Go Extinct?abstract

    Cited · Link answered, 19 October 2026 · Abstract only, 24 September 2026 · Texts · Review of the field

    The source reads: New databases show that there are more taxonomists describing species than ever before, and their number is increasing faster than the rate of species description.

What this does not establish

Read as the abstract only; how the taxonomists were counted is not in it. The next sentence gives the objections.

Later work looked for

Europe PMC, 2013 on, titles on taxonomists: a 2025 analysis questions whether author counts measure effort; now on the page.

Corrected

24 September 2026. Previously: “There are more taxonomists at work describing them than at any earlier point, and their number is growing faster than the rate of description itself.” The finding is one team’s, and it is disputed. It is now attributed, and the other side is reported beside it.

Claim 16 · checked 24 September 2026 · AI-assisted audit

Claim: Others doubt that counting authors on taxonomic papers measures effort, and most of the taxonomists who answered a poll for the 2011 analysis thought the number of experts in their own field was falling.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The past and future of known biodiversity: Rates, patterns, and projections of new species over timeDiscussion, on taxonomic effort

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Observational study: associations, not causes

    The source reads: Other authors have argued against using the number of authors on taxonomic papers as an indication of the effort needed to find new species ... the number of authors on a taxonomic paper may not actually reflect the number of dedicated taxonomists involved

  • Supports

    How Many Species Are There on Earth and in the Ocean?Assessment of Possible Limitations, Changes in taxonomic effort; Materials and Methods, Survey of Taxonomists

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes

    The source reads: a majority (79.4%) of experts that we polled in our taxonomic survey felt that the number of taxonomic experts is decreasing

    The 79.4 per cent is of the 548 who responded. About 2,938 experts received the request, so the view of those who did not answer is not known; the roughly 435 who said the number was falling are about 15 per cent of those reached.

  • Supports

    How Many Species Are There on Earth and in the Ocean?Materials and Methods, Survey of Taxonomists

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in people · Observational study: associations, not causes

    The source reads: about 2,938 experts received our request, of which 548 responded to our survey (response rate of 18.7%)

What this does not establish

The poll had a response rate of about 19 per cent, and asked for an impression rather than a count. The same authors noted that other factors, among them more amateur taxonomists and new tools, were offsetting the trend.

Later work looked for

As claim 16.

Corrected

24 September 2026. Previously: “” Added with claim 16, so that the disagreement is on the page.

24 September 2026. Previously: “Others doubt that counting authors on taxonomic papers measures effort, and most taxonomists polled for the 2011 analysis thought the number of experts in their own field was falling.” The 79.4 per cent is of the 548 who responded, out of about 2,938 reached (a response rate of 18.7 per cent), not of all those polled.

Claim 17 · checked 24 September 2026 · AI-assisted audit

The total is much larger than the catalogue

Claim: The total is much larger than the catalogue

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    How many species are there on Earth? Progress and problemssecond paragraph

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: This paper has since become the “default” estimate of the number of living species on the plant (8.75 million), even though approximately 80% of those species are hypothetical.

What this does not establish

On central estimates. The lowest end of the lowest published range, 2 million, is close to the catalogue.

Later work looked for

As claim 3.

Claim 18 · checked 24 September 2026 · AI-assisted audit

Claim: A widely cited 2011 analysis estimated roughly 8.7 million eukaryotic species, of which about 2.2 million are marine, implying that around 86% of species on Earth and 91% of those in the ocean had not yet been described.

Kind
What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    How Many Species Are There on Earth and in the Ocean?abstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Model

    The source reads: it predicts ∼8.7 million (±1.3 million SE) eukaryotic species globally, of which ∼2.2 million (±0.18 million SE) are marine ... our results suggest that some 86% of existing species on Earth and 91% of species in the ocean still await description

  • Supports

    How many species are there on Earth? Progress and problemssummary paragraph

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: The study by Mora and colleagues [4] has become very widely cited and used, and deservedly so.

What this does not establish

An extrapolation from how species are grouped into genera, families and orders, not a count. The percentages compare it with the 1.2 million species catalogued then, not with today’s catalogue. Its prokaryote figure is only a lower bound, and it did not use DNA-based species counts.

Other readings

Lower and higher totals are reported in claims 22 and 23.

Later work looked for

Europe PMC, 2014 on, "species on Earth": the 2023 Perspective reviews it as the default figure and reports DNA-based estimates for several groups that are much larger.

Claim 19 · checked 24 September 2026 · AI-assisted audit

Claim: It became the default figure,

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    How many species are there on Earth? Progress and problemssecond paragraph

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: This paper has since become the “default” estimate of the number of living species on the plant (8.75 million)

Corrected

24 September 2026. Previously: “That estimate is contested in detail but not in kind.” “Not in kind” held only against the lower rival. Estimates built on DNA put several groups far above it, so the disagreement runs in both directions.

Claim 20 · checked 24 September 2026 · AI-assisted audit

Claim: and it is challenged from both sides.

Kind
Disputed. A contested point, where the page reports a side or the disagreement.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Follows from claims 22 and 23: one published total is lower, and several group totals are higher.

  • Context

    Can We Name Earth's Species Before They Go Extinct?abstract

    Cited · Link answered, 19 October 2026 · Abstract only, 24 September 2026 · Texts · Review of the field

    The source reads: We argue that the number of species on Earth today is 5 ± 3 million, of which 1.5 million are named.

  • Context

    How many species are there on Earth? Progress and problemsfifth paragraph

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: Mora and colleagues generally did not incorporate the vast species numbers revealed through molecular analyses (e.g., metabarcoding).

Other readings

The 2023 Perspective credits the 2011 analysis as a transformative advance and argues only that it should not be treated as the final word.

Claim 21 · checked 24 September 2026 · AI-assisted audit

Claim: Costello, May and Stork put the total lower, at 5 million give or take 3, with 1.5 million named.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Partly checked. Only part of the source could be read. What was not read is listed.

  • Supports

    Can We Name Earth's Species Before They Go Extinct?abstract

    Cited · Link answered, 19 October 2026 · Abstract only, 24 September 2026 · Texts · Review of the field

    The source reads: We argue that the number of species on Earth today is 5 ± 3 million, of which 1.5 million are named.

What this does not establish

Read as the abstract only, so how the figure was reached was not read. The paper counts 1.5 million named; the Catalogue now lists more (claim 12).

Later work looked for

As claim 19.

Corrected

24 September 2026. Previously: “The main rival puts the total at 5 million give or take 3, with 1.5 million named, which still leaves the described fraction a minority.” Named, rather than called the main rival, which no source read establishes. The closing clause was not true across the whole range: at 2 million, 1.5 million named would be a majority. Claim 24 now makes the point for central estimates.

Claim 22 · checked 24 September 2026 · AI-assisted audit

Claim: Estimates built on DNA run far higher, to around 20 million insects alone once species that look identical are counted separately.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    How many species are there on Earth? Progress and problemsparagraph on insects

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: morphologically cryptic species revealed by molecular analyses. ... each insect species initially delimited by morphology might conceal (on average) 3.1 cryptic species [9]. Combined with projections of approximately 6 million morphology-based insect species, this yields estimates of approximately 20 million insect species [9].

  • Qualifies

    How many species are there on Earth? Progress and problemsparagraph on insects

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: Nevertheless, these extrapolations could be overestimates for two main reasons.

What this does not establish

An extrapolation from studies of cryptic species, which the review itself says could be too high: large barcoding studies find fewer cryptic species, and undescribed species may hide fewer than described ones.

Later work looked for

The Perspective is the most recent overview found (Europe PMC, 2014 on, "species on Earth").

Corrected

24 September 2026. Previously: “” The page reported only the lower rival. The higher side, from molecular data, is reported in a 2023 review of the 2011 estimate.

Claim 23 · checked 24 September 2026 · AI-assisted audit

Claim: At the centre of every one of these ranges, most species are still unnamed.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Follows from claims 19, 22 and 23: 1.5 of 5 million named on the lowest central estimate, and smaller shares on the others.

Corrected

24 September 2026. Previously: “” Replaces a clause that claimed the described fraction was a minority on every estimate, which the lower end of one range does not bear out.

Claim 24 · checked 24 September 2026 · AI-assisted audit

Why the estimates disagree

Claim: Why the estimates disagree

Kind
Framing. Signposting. It asserts nothing a source could check.

Where the estimates disagree

Claim: Where the estimates disagree

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: The methods disagree by an order of magnitude, and Mora and colleagues set them out side by side.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    How Many Species Are There on Earth and in the Ocean?Introduction; Table 1

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: see detailed review of available methods, estimates, and limitations in Table 1

What this does not establish

The estimates in Table 1 cover different groups, so they are not all estimates of the same total.

Claim 27 · checked 24 September 2026 · AI-assisted audit

Claim: Host-specificity ratios gave Erwin 30 million arthropods in the tropics.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    How Many Species Are There on Earth and in the Ocean?Table 1, Host-specificity and spatial ratios

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: Erwin [9] estimated 30 million species of arthropods in the tropics

What this does not establish

Read as summarised in the 2011 analysis; Erwin’s paper was not read.

Claim 28 · checked 24 September 2026 · AI-assisted audit

Claim: Known-to-unknown ratios gave Hodkinson and Casson 1.84 to 2.57 million insects worldwide.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    How Many Species Are There on Earth and in the Ocean?Table 1, Known to unknown ratios

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: they estimated between 1.84 and 2.57 million species of insects globally

What this does not establish

Read as summarised in the 2011 analysis; the original was not read.

Claim 29 · checked 24 September 2026 · AI-assisted audit

Claim: Asking taxonomists gave a range of 3 to 100 million species.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    How Many Species Are There on Earth and in the Ocean?Introduction

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: our best approximation to the total number of species is based on the opinion of taxonomic experts, whose estimates range between 3 and 100 million species [1]

Claim 30 · checked 24 September 2026 · AI-assisted audit

Claim: Extrapolating from well-studied groups assumes that poorly studied groups behave similarly, and there is no guarantee they do.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    How Many Species Are There on Earth and in the Ocean?Table 1, limitations of ratios between taxa

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: locally estimated ratios between taxa may or may not be consistent at the global scale [3],[12] and because at least one group of organisms should be well known at the global scale, which may not always be true [15]

  • Supports

    How Many Species Are There on Earth and in the Ocean?Assessment of Possible Limitations, Completeness of taxonomic inventories

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Model

    The source reads: These results suggest that our estimates for Chromista and Fungi (in the ocean) need to be considered with caution due to the incomplete nature of their data.

Claim 31 · checked 24 September 2026 · AI-assisted audit

Claim: Fungi are a stark case.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Follows from claims 33 to 35.

Corrected

24 September 2026. Previously: “Fungi are the starkest case.” Bacteria are starker on the page’s own figures (claims 37 and 38), and no source ranks the groups.

Claim 32 · checked 24 September 2026 · AI-assisted audit

Claim: The Catalogue of Life’s August 2026 release lists about 174,000 described species.

Kind
Present-day figure. A count, survey or report finding, as the named source gives it.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

As claim 12: the Extended Release.

Later work looked for

Release COL26.8 XR is a fixed version and its counts do not change. The Catalogue’s home page moved on to release COL26.9 XR, issued 25 September 2026, on 19 October 2026; the page dates the figure to the release rather than following it.

Corrected

19 October 2026. Previously: “The Catalogue of Life lists about 174,000 described species.” The Catalogue’s home page moved to a later release and stopped carrying the figure; it is now dated to the August 2026 release and cited to that versioned release.

Claim 33 · checked 19 October 2026 · AI-assisted audit

Claim: A 2017 review of the evidence put the real total at 2.2 to 3.8 million, against 120,000 species accepted at the time: about 3 to 5 per cent named.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Fungal Diversity Revisited: 2.2 to 3.8 Million Speciesabstract; section proposing the updated range

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: the actual range is properly estimated at 2.2 to 3.8 million. With 120,000 currently accepted species, it appears that at best just 8%, and in the worst case scenario just 3%, are named so far.

  • Supports

    Fungal Diversity Revisited: 2.2 to 3.8 Million Speciesabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: We conclude that the commonly cited estimate of 1.5 million species is conservative and that the actual range is properly estimated at 2.2 to 3.8 million.

    The review’s 8 per cent is 120,000 of the 1.5 million it calls conservative. Within its own range, 120,000 of 3.8 million is 3.2 per cent and of 2.2 million 5.5 per cent, which is the page’s 3 to 5.

What this does not establish

The percentages are arithmetic on the review’s range and its count of 120,000 accepted species; against today’s 174,000 the named share would be about 5 to 8 per cent.

Later work looked for

Crossref and OpenAlex, 2018 on, global fungal diversity: a larger sequence-based estimate, now claim 35.

Corrected

24 September 2026. Previously: “A 2017 review of the evidence put the real total at 2.2 to 3.8 million, and concluded that at best 8 per cent of fungi have names, and at worst 3 per cent.” The review's 8 per cent is 120,000 of the commonly cited 1.5 million, which it calls conservative; within its own range of 2.2 to 3.8 million, 120,000 is 3.2 to 5.5 per cent.

Claim 34 · checked 24 September 2026 · AI-assisted audit

Claim: An analysis of fungal DNA from more than 200 studies has since put it higher, at about 6.3 million, which its authors call conservative.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Partly checked. Only part of the source could be read. What was not read is listed.

  • Supports

    High-throughput sequencing view on the magnitude of global fungal diversityabstract

    Cited · Link answered, 19 October 2026 · Abstract only, 24 September 2026 · Research in microbes · Observational study: associations, not causes

    The source reads: > 200 studies published until 2019 have generated over 250 million sequences of the primary mycological metabarcoding marker ... The Chao-1 estimate of the total extant fungal diversity based on this dataset is 6.28 million taxa, representing a conservative estimate of global fungal species richness.

  • Supports

    How many species are there on Earth? Progress and problemsparagraph on fungi

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: They extrapolated from this sampling to conservatively project 6.3 million fungal species.

What this does not establish

Read as the abstract, and as reported in the 2023 review. The unit is a sequence cluster at 97 per cent similarity, standing in for a species, and the authors say the method’s limitations have to be taken into account.

Later work looked for

This is the newer work; nothing later found that revises it.

Corrected

24 September 2026. Previously: “” The 2017 range was reported as the current figure. A later sequence-based estimate, reported in the 2023 review of the field, is higher.

Claim 35 · checked 24 September 2026 · AI-assisted audit

Whether microbial diversity is countable at all

Claim: Whether microbial diversity is countable at all

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: One analysis of microbial scaling laws put global diversity at as many as a trillion species.

Kind
What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Scaling laws predict global microbial diversitySignificance

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in microbes · Model

    The source reads: Using this scaling law combined with the lognormal model of biodiversity, we predict that Earth is home to as many as 1 trillion

  • Supports

    Scaling laws predict global microbial diversityDiscussion

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in microbes · Model

    The source reads: Powerful relationships like those documented here and a greater unified study of commonness and rarity will greatly contribute to finding the potentially 99.999% of microbial taxa that remain undiscovered.

What this does not establish

A prediction from a scaling law fitted to local communities and carried to the whole planet, not a count. The paper’s range is a hundred billion to a trillion microbial species; the trillion is its upper end.

Other readings

The 2019 census, claim 38, says it refutes the trillion.

Later work looked for

Europe PMC, 2016 on, replies and later estimates: the 2019 census and the 2021 exchange, all on the page.

Corrected

24 September 2026. Previously: “One analysis of microbial scaling laws put global diversity near a trillion species.” The paper's own range is 10^11 to 10^12 microbial species, and its headline is 'as many as 1 trillion'; 'near a trillion' dropped the lower end, a tenth of that.

Claim 37 · checked 24 September 2026 · AI-assisted audit

Claim: A census of 1.7 billion ribosomal RNA sequences from 492 studies arrived at 2.2 to 4.3 million prokaryotic operational taxonomic units instead, and says in its abstract that it refutes the trillion.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    A census-based estimate of Earth's bacterial and archaeal diversityabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in microbes · Observational study: associations, not causes

    The source reads: we analyzed over 1.7 billion 16S ribosomal RNA amplicon sequences in the V4 hypervariable region obtained from 492 studies worldwide ... we further estimate that there exist about 2.2–4.3 million full-length OTUs worldwide

  • Supports

    A census-based estimate of Earth's bacterial and archaeal diversityabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in microbes · Observational study: associations, not causes

    The source reads: Our estimates constrain the extent of a poorly quantified rare microbial biosphere and refute recent predictions that there exist trillions of prokaryotic OTUs.

What this does not establish

The census’s direct estimate is 0.8 to 1.6 million units for the short stretch of gene it sequenced; 2.2 to 4.3 million is its conversion to the full-length gene.

Later work looked for

Europe PMC, 2019 on, replies to the census: a 2021 Formal Comment and the authors’ response, both now on the page.

Claim 38 · checked 24 September 2026 · AI-assisted audit

Claim: A formal comment by John Wiens argued that bacteria living only in particular insects and other animals put the total in the hundreds of millions or billions instead.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Vast (but avoidable) underestimation of global biodiversityabstract; paragraph giving the projections

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in microbes · Review of the field

    The source reads: this Formal Comment suggests instead that there are more likely hundreds of millions or billions of species, and that the majority of these are bacteria associated with insects and other animals ... These projections are based on refined estimates of host-specific bacterial richness

What this does not establish

The comment’s own projections rest on assumptions about how many bacterial species are unique to each host, and span 0.18 to 4.2 billion species.

Later work looked for

Nothing later found that settles the exchange.

Corrected

24 September 2026. Previously: “” The census was reported with no reply. It had one in the same journal, and the page now gives both sides.

Claim 39 · checked 24 September 2026 · AI-assisted audit

Claim: The census authors replied that thousands of animal samples were in their data.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

Corrected

24 September 2026. Previously: “” Added with claim 39.

Claim 40 · checked 24 September 2026 · AI-assisted audit

Claim: More than five orders of magnitude separate the census from the trillion,

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Arithmetic on claims 37 and 38: a trillion against 2.2 to 4.3 million is a factor of about 230,000 to 450,000, and against the census’s direct 0.8 to 1.6 million it is about a million.

Corrected

24 September 2026. Previously: “Six orders of magnitude separate them,” Against the full-length figures the page quotes, the gap is five and a half orders, not six.

24 September 2026. Previously: “Nearly six orders of magnitude separate the census from the trillion,” A trillion against the census's 2.2 to 4.3 million full-length units is a ratio of 2.3 to 4.5 x 10^5, 5.4 to 5.7 orders of magnitude, not nearly six.

Claim 41 · checked 24 September 2026 · AI-assisted audit

Claim: although both count the same unit: sequences grouped at 97 per cent similarity.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    A census-based estimate of Earth's bacterial and archaeal diversityabstract; Introduction

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in microbes · Observational study: associations, not causes

    The source reads: (OTUs, 16S-V4 gene clusters at 97% similarity), a commonly used measure of microbial richness ... Locey and colleagues [6] even predicted that there exist trillions of microbial OTUs (at 97% similarity)

Corrected

24 September 2026. Previously: “and most of that gap is method: where you draw a species boundary in organisms that exchange genes freely and reproduce without sex.” The page put the gap down to where the species boundary is drawn. Both estimates use the same boundary, a 97 per cent sequence cluster; the census attributes the gap to extrapolation. The boundary question is real but separate, and is now stated as such. “Freely” and “reproduce without sex” had no source.

Claim 42 · checked 24 September 2026 · AI-assisted audit

Claim: That gap is method, a scaling law carried from single communities to the whole planet against a statistical census of what sequencing has found.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    A census-based estimate of Earth's bacterial and archaeal diversityIntroduction

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in microbes · Observational study: associations, not causes

    The source reads: based on an extrapolation of empirical scaling laws of local diversity in individual communities to global scales

  • Supports

    Response to “Vast (but avoidable) underestimation of global biodiversity”third paragraph

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in microbes · Review of the field

    The source reads: our estimates of global bacterial (and archaeal) richness, discussed in our main article, are based on 7 alternative well-established estimation methods founded on concrete statistical models

  • Context

    Scaling laws predict global microbial diversityabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in microbes · Model

    The source reads: We document a universal dominance scaling law that holds across 30 orders of magnitude

What this does not establish

This is the census authors’ account of the difference. Locey and Lennon’s own abstract presents the scaling law as holding across 30 orders of magnitude.

Corrected

24 September 2026. Previously: “” See claim 42.

Claim 43 · checked 24 September 2026 · AI-assisted audit

Claim: Beneath both lies a harder question, where to draw a species boundary in organisms that pass genes between lineages,

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    How Many Species Are There on Earth and in the Ocean?Results, on prokaryotes

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Model

    The source reads: for prokaryotes, the species concept tolerates a much higher degree of genetic dissimilarity than in most eukaryotes [26],[27]; additionally, due to horizontal gene transfers among phylogenetic clades, species take longer to isolate in prokaryotes than in eukaryotes

Corrected

24 September 2026. Previously: “” See claim 42.

Claim 44 · checked 24 September 2026 · AI-assisted audit

Claim: and the census authors allow that finer genetic resolution may reveal far more kinds than their unit does.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Response to “Vast (but avoidable) underestimation of global biodiversity”last paragraph

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in microbes · Review of the field

    The source reads: it may well be that at finer phylogenetic resolutions, e.g., at bacterial strain level, host specificity and bacterial richness are substantially higher. In particular, future whole-genome sequencing surveys may well reveal the existence of far more genomic clusters and ecotypes than 16S-based OTUs.

Corrected

24 September 2026. Previously: “” See claim 42.

Claim 45 · checked 24 September 2026 · AI-assisted audit

Claim: That boundary is a convention, not a discovery.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The 97 per cent threshold is a commonly used measure, not a natural break, and different communities of taxonomists draw species at different levels.

  • Context

    How Many Species Are There on Earth and in the Ocean?Assessment of Possible Limitations, Species definitions

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Model

    The source reads: Different taxonomic communities (e.g., zoologists, botanists, and bacteriologists) use different levels of differentiation to define a species.

  • Context

    A census-based estimate of Earth's bacterial and archaeal diversityabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in microbes · Observational study: associations, not causes

    The source reads: Qualitatively similar results are also obtained for other 16S similarity thresholds (90%, 95%, and 99%).

Claim 46 · checked 24 September 2026 · AI-assisted audit

Claim: Three totals, counting different things

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The three figures below are a count of described species in every kingdom, a model of eukaryotes, and a prediction for microbes.

Corrected

24 September 2026. Previously: “Three totals, depending on what counts as a species” The totals differ mainly in what they cover and how they were reached, not in their definition of a species (claim 42).

Claim 47 · checked 24 September 2026 · AI-assisted audit

Claim: 2.4 million

Kind
Present-day figure. A count, survey or report finding, as the named source gives it.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Catalogue of Life, release COL26.8 XR (26 August 2026): species by domainclassification of release COL26.8 XR, domain Eukaryota

    Cited · Link answered, 19 October 2026 · Read in full, 19 October 2026 · Reference work

    The source reads: "id":"CS5HF","rank":"domain","status":"accepted","count":2440722,"childCount":7,"name":"Eukaryota"

    The release counts 2,440,722 species of eukaryotes. Bacteria, archaea and viruses are listed beside them as separate groups and are not in this figure.

What this does not establish

As claim 4.

Later work looked for

Release COL26.8 XR is a fixed version and its counts do not change. The Catalogue’s home page moved on to release COL26.9 XR, issued 25 September 2026, on 19 October 2026; the page dates the figure to the release rather than following it.

Claim 48 · checked 19 October 2026 · AI-assisted audit

Claim: Formally described

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: The Catalogue of Life, August 2026 release: animals, plants, fungi, chromists and protozoa.

Kind
Present-day figure. A count, survey or report finding, as the named source gives it.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Catalogue of Life, release COL26.8 XR (26 August 2026): species in the kingdoms of eukaryotesclassification of release COL26.8 XR, kingdoms under Eukaryota

    Cited · Link answered, 19 October 2026 · Read in full, 19 October 2026 · Reference work

    The source reads: "rank":"kingdom","status":"accepted","count":1780634,"childCount":17311,"name":"Animalia" ... "rank":"kingdom","status":"accepted","count":72698,"childCount":15,"name":"Chromista" ... "rank":"kingdom","status":"accepted","count":174018,"childCount":14272,"name":"Fungi" ... "rank":"kingdom","status":"accepted","count":410502,"childCount":31,"name":"Plantae" ... "rank":"kingdom","status":"accepted","count":2870,"childCount":89,"name":"Protozoa"

    The five kingdoms sum to 2,440,722, the count for Eukaryota.

Later work looked for

Release COL26.8 XR is a fixed version and its counts do not change. The Catalogue’s home page moved on to release COL26.9 XR, issued 25 September 2026, on 19 October 2026; the page dates the figure to the release rather than following it.

Corrected

19 October 2026. Previously: “The Catalogue of Life, August 2026 release, across every kingdom.” The 2.4 million is the release’s count for its five kingdoms of eukaryotes. Bacteria, archaea and viruses are counted separately, so "every kingdom" overstated it.

Claim 50 · checked 19 October 2026 · AI-assisted audit

Claim: 8.7 million

Kind
What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

As claim 19: a model estimate, with a standard error of 1.3 million.

Claim 51 · checked 24 September 2026 · AI-assisted audit

Claim: Estimated eukaryotes

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: From the 2011 analysis.

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: About 2.2 million of them marine.

Kind
What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    How Many Species Are There on Earth and in the Ocean?Results

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Model

    The source reads: Restricting this approach to marine taxa resulted in a prediction of 2.21 million eukaryote species in the world's oceans

What this does not establish

A model estimate, with a standard error of 0.18 million.

Claim 54 · checked 24 September 2026 · AI-assisted audit

Claim: ~1 trillion

Kind
What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Scaling laws predict global microbial diversitySignificance

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in microbes · Model

    The source reads: we predict that Earth is home to as many as 1 trillion

What this does not establish

As claim 37: a prediction, not a count, and the upper end of a range that runs from a hundred billion.

Other readings

The 2019 census puts prokaryotes at a few million sequence clusters (claim 38).

Claim 55 · checked 24 September 2026 · AI-assisted audit

Claim: Microbial species, by scaling law

Kind
Framing. Signposting. It asserts nothing a source could check.

Corrected

24 September 2026. Previously: “If microbes are counted the same way” The trillion does not come from counting microbes as animal species are counted. It is a prediction from a scaling law, and the label now says so.

Claim: From scaling laws extrapolated to the whole planet, and disputed: a sequence census puts prokaryotes at a few million instead.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    A census-based estimate of Earth's bacterial and archaeal diversityIntroduction

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in microbes · Observational study: associations, not causes

    The source reads: Locey's extrapolation of empirical scaling laws from local to global scales and across several orders of magnitude has been criticized and remains controversial

  • Supports

    A census-based estimate of Earth's bacterial and archaeal diversityabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in microbes · Observational study: associations, not causes

    The source reads: we further estimate that there exist about 2.2–4.3 million full-length OTUs worldwide

Later work looked for

As claim 38.

Corrected

24 September 2026. Previously: “From microbial scaling laws, and disputed: a sequence census puts prokaryotes at a few million instead.” Says what the method does, which is what the dispute is about (claim 43).

Claim 57 · checked 24 September 2026 · AI-assisted audit

What the catalogue will never hold

Claim: What the catalogue will never hold

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Section title. That some species will go extinct undescribed follows from claims 61 and 63; how many is what the section says cannot be known.

Claim 58 · checked 24 September 2026 · AI-assisted audit

How many we will lose before we meet them

Claim: How many we will lose before we meet them

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: Whether extinction is outrunning description is disputed.

Kind
Disputed. A contested point, where the page reports a side or the disagreement.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The two sides are claims 61 and 62.

Other readings

Mora and colleagues expect losses before description; Costello, May and Stork call that worry overstated.

Claim 60 · checked 24 September 2026 · AI-assisted audit

Claim: Mora and colleagues expect the slow advance of description to leave species extinct before anyone knew they existed.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    How Many Species Are There on Earth and in the Ocean?Discussion, second paragraph

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Model

    The source reads: our results also suggest that this slow advance in the description of species will lead to species becoming extinct before we know they even existed

What this does not establish

The expectation rests on an extinction rate of 100 to 1,000 times background, which the paper takes from another source, and on its assumed description rate.

Claim 61 · checked 24 September 2026 · AI-assisted audit

Claim: Costello, May and Stork answer that the despair rests on overestimates of how many species there are, on a belief that the expertise to describe them is shrinking, and on alarmist extinction rates.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Partly checked. Only part of the source could be read. What was not read is listed.

  • Supports

    Can We Name Earth's Species Before They Go Extinct?abstract

    Cited · Link answered, 19 October 2026 · Abstract only, 24 September 2026 · Texts · Review of the field

    The source reads: Some people despair that most species will go extinct before they are discovered. However, such worries result from overestimates of how many species may exist, beliefs that the expertise to describe species is decreasing, and alarmist estimates of extinction rates.

What this does not establish

Read as the abstract only.

Corrected

24 September 2026. Previously: “Costello, May and Stork answer that the despair rests on overestimates of how many species there are and on alarmist extinction rates, which they put at 0.01 to 1 per cent per decade, and that taxonomists are now being added faster than species are being described.” The old wording made 0.01 to 1 per cent the alarmist rates; it is the paper’s own range, which it calls poorly quantified. “Taxonomists are being added faster than species are being described” misread the paper, which says the number of taxonomists is growing faster than the rate of description; that point is made once, in claim 16. The paper’s third reason, a belief that expertise is shrinking, was missing.

Claim 62 · checked 24 September 2026 · AI-assisted audit

Claim: Their own range for extinction is 0.01 to 1 per cent per decade, at most 5, and they call it poorly quantified.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Partly checked. Only part of the source could be read. What was not read is listed.

  • Supports

    Can We Name Earth's Species Before They Go Extinct?abstract

    Cited · Link answered, 19 October 2026 · Abstract only, 24 September 2026 · Texts · Review of the field

    The source reads: Extinction rates are, however, poorly quantified, ranging from 0.01 to 1% (at most 5%) per decade.

What this does not establish

Read as the abstract only, which does not say how the range was derived.

Corrected

24 September 2026. Previously: “” See claim 62.

Claim 63 · checked 24 September 2026 · AI-assisted audit

Claim: The number of lineages that will disappear without ever being recorded cannot be measured, because measuring it would require the record that does not exist.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The page’s own reasoning. It can be estimated, as claims 61 to 63 do; it cannot be counted.

  • Context

    How many species are there on Earth? Progress and problemslast paragraph

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: Soon, we may not be estimating how many species there are on Earth. We will be estimating how many there were.

Claim 64 · checked 24 September 2026 · AI-assisted audit

What lives in habitats nobody has sampled

Claim: What lives in habitats nobody has sampled

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: Existing catalogues are biased towards species that are large, abundant and widely spread,

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    How Many Species Are There on Earth and in the Ocean?Discussion, third paragraph

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: Previous studies have indicated that current catalogues of species are biased towards conspicuous species with large geographical ranges, body sizes, and abundances

What this does not establish

Reported by the 2011 analysis from earlier studies, which were not read.

Claim 67 · checked 24 September 2026 · AI-assisted audit

Claim: so what is missing should be the opposite: small ranges and small bodies, in hotspots and in less explored places such as the deep sea and the soil.

Kind
Hypothesis. A proposed explanation, not an established one.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    How Many Species Are There on Earth and in the Ocean?Discussion, third paragraph

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: This suggests that the bulk of species that remain to be discovered are likely to be small-ranged and perhaps concentrated in hotspots and less explored areas such as the deep sea and soil; although their small body-size and cryptic nature

What this does not establish

An inference from the bias in the catalogue, stated by its authors as likely rather than shown. They add that many could be found close to home.

Corrected

24 September 2026. Previously: “so what is missing should be the opposite: small ranges, small bodies, and the deep sea and the soil.” Brought closer to the source, which names hotspots and calls these places less explored.

Claim 68 · checked 24 September 2026 · AI-assisted audit

Claim: For fungi, a 2017 review adds little-explored habitats such as lichens, and specimens already in collections that nobody has yet studied.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Fungal Diversity Revisited: 2.2 to 3.8 Million Speciesabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: We further draw attention to undescribed species awaiting discovery in biodiversity hot spots in the tropics, little-explored habitats (such as lichen-inhabiting fungi), and material in collections awaiting study.

  • Supports

    Fungal Diversity Revisited: 2.2 to 3.8 Million Speciessection on existing reference collections

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: most reference collections of fungi, whether of dried specimens (fungaria) or living cultures (culture or microbial resource collections), include material that is not named to the species level

What this does not establish

The review’s lichen example is the lichenicolous fungi, which grow on lichens: 457 species known in 1976 and more than 1,800 by 2016.

Corrected

24 September 2026. Previously: “” Added in place of a sentence listing unsampled habitats that no cited source carried (see the retired claim 66).

Claim 69 · checked 24 September 2026 · AI-assisted audit

Finishable, or not

Claim: Finishable, or not

Kind
Framing. Signposting. It asserts nothing a source could check.

The number is around 8–10 million eukaryotes

Claim: The number is around 8–10 million eukaryotes

Kind
Hypothesis. A proposed explanation, not an established one.
Review
Source checked. The cited passage was read, and it says this.

Other readings

Costello, May and Stork put the total lower (claim 22); estimates built on DNA put several groups far higher (claims 23 and 35).

Claim 71 · checked 24 September 2026 · AI-assisted audit

Claim: If extrapolation from taxonomic hierarchy is sound, the total for animals, plants, fungi and protists settles in single-digit millions, and the cataloguing project is finishable.

Kind
Hypothesis. A proposed explanation, not an established one.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    How Many Species Are There on Earth and in the Ocean?abstract; Results

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Model

    The source reads: the higher taxonomic classification of species (i.e., the assignment of species to phylum, class, order, family, and genus) follows a consistent and predictable pattern from which the total number of species in a taxonomic group can be estimated

  • Qualifies

    How many species are there on Earth? Progress and problemsfifth paragraph

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Texts · Review of the field

    The source reads: Mora and colleagues generally did not incorporate the vast species numbers revealed through molecular analyses (e.g., metabarcoding).

What this does not establish

“Finishable” is the page’s reading of the timescale in claim 73.

Other readings

The 2023 review argues that the method missed the species that DNA reveals, which would raise the total well above single-digit millions for several groups.

Claim 72 · checked 24 September 2026 · AI-assisted audit

Claim: At the description rates and costs Mora and colleagues assumed, finishing it would take about 1,200 years, 303,000 taxonomists and US$364 billion.

Kind
What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

The assumed rate was 6,200 eukaryote species a year, from data to 2006. The 2025 analysis finds the fastest recent years above 16,000 new species of all kinds, so the time would be shorter at today’s rate.

Later work looked for

Europe PMC, 2013 on, rates of description: the 2025 analysis (claim 15), recorded in limits.

Claim 73 · checked 24 September 2026 · AI-assisted audit

The number is effectively unbounded

Claim: The number is effectively unbounded

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Heading for the view in claim 75. A trillion is finite; “effectively” marks it as too large to catalogue.

Other readings

The 2019 census puts prokaryotes in the low millions (claim 38).

Claim 74 · checked 24 September 2026 · AI-assisted audit

Claim: If the scaling laws behind the trillion hold, the total is so large that a complete catalogue is not a meaningful goal.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

A conditional on claim 37. Whether a catalogue of that size is a meaningful goal is the page’s judgement.

  • Context

    Scaling laws predict global microbial diversityabstract

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Research in microbes · Model

    The source reads: In combining this scaling law with the lognormal model of biodiversity, we predict that Earth is home to upward of 1 trillion

Other readings

The census in claim 38 rejects the premise.

Corrected

24 September 2026. Previously: “If microbial lineages are counted the way animal species are, the total may be so large that a complete catalogue is not a meaningful goal.” The condition the trillion rests on is a scaling law, not counting microbes as animal species are counted.

Claim 75 · checked 24 September 2026 · AI-assisted audit

Claim: On this view the right question is not how many species exist but what kinds of life exist, and how they are distributed.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The page’s reading of what follows if claim 75’s condition holds.

Claim 76 · checked 24 September 2026 · AI-assisted audit

What was read