
Number of species on Earth estimated at 8.7M (2011) - lifeisstillgood
http://www.nature.com/news/2011/110823/full/news.2011.498.html
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IshKebab
Counting species is like measuring coastlines.

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osrec
Interesting that Hindu scriptures (the Bhagavat Puran specifically) mentioned
84 lakh (8.4 million) species. An eerily accurate estimate!

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dalke
That's 8.7M eukaryotic species. There are many more prokaryotic species,
though the concept of "species" becomes quite difficult.

For this to be 'eerie' rather than a coincidence, there should be some
explanation of why prokaryotes shouldn't be included in the count, and what
'species' means.

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nonbel
Interesting, originally they only counted as one species and there is still
controversy to this day about the issue:

"Initially, prokaryotes were treated as only a single species which could
develop a great variety of shapes (pleomorphism)."
[http://onlinelibrary.wiley.com/doi/10.1111/j.1574-6976.2001....](http://onlinelibrary.wiley.com/doi/10.1111/j.1574-6976.2001.tb00571.x/pdf)

I wonder if they will get plutoed eventually.

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dalke
I read (er, skimmed) that article too, while trying to get an idea of just how
many prokaryotics species there were. :) I quickly realized I was way out of
my depth, but given the 5,000 described species and the "hitherto classified
prokaryotic species account for a very small portion of the real prokaryote
diversity", I figured it as safe to assume there were a lot more.

> I wonder if they will get plutoed eventually.

... No? Though I'm not sure what 'plutoed' means, with 5,000 described
species, making up both the Archaea and Bacteria domains (the third domain is
Eukaryota), it's hard to imagine any sort of demotion or additional
reclassificaton.

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nonbel
I was thinking that if no agreement can be made and the number of species
keeps rising, the prokaryotes would get split into one or a few species and
the current species would become sub-species (or some other appropriate
label). This would be similar to how astronomers kept finding objects like
pluto they didn't want to call planets.

By the way, my spell check doesn't even recognize the word prokaryote
(although it does have eukaryote).

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dalke
The prokaryotes are already split into two domains, so there's no way they
will be called subspecies of a single species.

Note that all the millions of eukaryotes fit into one domain. The domain is a
much higher level than species. It's Domain, Kingdom, Phylum, Class, Order,
Family, Genus, Species. See
[https://en.wikipedia.org/wiki/Bacterial_taxonomy](https://en.wikipedia.org/wiki/Bacterial_taxonomy)
.

Thus, it's hugely more likely that the intermediate classification terms will
be used, rather than group everything a subspecies of a small number of
species.

Even if there are billions of prokaryotic species.

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hyperion2010
Title is misleading. To quote the article "There are 8.7 million eukaryotic
species on our planet — give or take 1.3 million." 8.7M is way too low for a
total species count that includes bacteria much less archaea.

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BurningFrog
Side note: Using the term "species" for non sexually reproducing organisms
like bacteria mostly confuses things.

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randyrand
Why? What do you call different types of bacteria?

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cjhveal
Bacteria are indeed grouped into species. The _coli_ of _Escherichia coli_ is
an identifier for the species. However, species in general is a pretty
nebulous term.

One definition of species is the maximal set of individuals that are pairwise
sexually capable of producing viable offspring (which is obviously non-
sensical when we're talking of organisms which reproduce asexually.) Other
methods of defining species rely on physical or genetic similarity, which are
troublesome due to parallel & convergent evolution (where two phylogenically
distinct populations arrive at the same morphology/phenotype) and horizontal
gene transfer (transfering genetic information between individuals without
directly producing offspring---fairly common in prokaryotes). So it can get a
little bit hazy, but taxonomists carry on nonetheless as best they can.

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mc808
"The DAG of Life" doesn't have quite as nice a ring to it.

