# How many macroscopic (naked-eye visible) single-celled beings are there? **URL:** \ **Category:** Factual Questions\ **Created:** [November 21, 2008, 11:23am UTC](https://boards.straightdope.com/t/how-many-macroscopic-naked-eye-visible-single-celled-beings-are-there/473807 "2008-11-21T11:23:11Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [November 21, 2008, 11:23am UTC](https://boards.straightdope.com/t/how-many-macroscopic-naked-eye-visible-single-celled-beings-are-there/473807/1 "2008-11-21T11:23:11Z")
[Inspired by a living fossil, the _Gromia sphaerica_, a _grape-sized_ Protist.](http://www.eurekalert.org/pub_releases/2008-11/uota-dog111308.php) None of the reports I’ve read indicate that this wee beastie is the only macroscopic single-celled being, but I’ve never heard of any others. How many are there? What is the largest single-celled being? Note: I don’t care about things that are single-celled only in that they are made up of billions or trillions of single cells. I know about slime molds, mosses, lichens, ferns, and Bill Gates. I even know about gigantic things growing under the surface of the Pacific Northwest. I don’t care if they are formed of loose collections of single cells, either: This thread is about single-celled beings that _themselves_ can be seen with the unaided (human) eye. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [November 21, 2008, 12:26pm UTC](https://boards.straightdope.com/t/how-many-macroscopic-naked-eye-visible-single-celled-beings-are-there/473807/2 "2008-11-21T12:26:40Z")
There’s a type of algae that is single celled but quite large; I found a [mention](http://bio.classes.ucsc.edu/bio170/oldsite/C.fragile/Morphology.html) of it growing to 10 meters in size. It has many cell nuclei, but no internal cell walls. ---
**Author:** ![Sigene](https://avatars.discourse-cdn.com/v4/letter/s/df788c/32.png) [@Sigene](https://boards.straightdope.com/u/Sigene)\ **Post date:** [November 21, 2008, 12:30pm UTC](https://boards.straightdope.com/t/how-many-macroscopic-naked-eye-visible-single-celled-beings-are-there/473807/3 "2008-11-21T12:30:10Z")
> [@Derleth](#): > > I know about slime molds, mosses, lichens, ferns, and Bill Gates. . It is inappropriate in this forum to say disparaging things about lichens and mosses.😃 ---
**Author:** ![Wiltshire](https://avatars.discourse-cdn.com/v4/letter/w/ea5d25/32.png) [@Wiltshire](https://boards.straightdope.com/u/Wiltshire)\ **Post date:** [November 21, 2008, 1:11pm UTC](https://boards.straightdope.com/t/how-many-macroscopic-naked-eye-visible-single-celled-beings-are-there/473807/4 "2008-11-21T13:11:29Z")
How rude. What have those slime molds ever done to you? Hm, _codium fragile_ seems hard to beat, though it feels a bit like cheating. How’s this: [Acetabularia - Wikipedia](http://en.wikipedia.org/wiki/Acetabularia), single nucleus, up to 10 cm. Browsing around a little, there appear to be quite a few of lesser giants. [http://www.glerl.noaa.gov/seagrant/GLWL/Algae/Chrysophyta/Cards/Botrydium.html](http://www.glerl.noaa.gov/seagrant/GLWL/Algae/Chrysophyta/Cards/Botrydium.html) [Polychaos dubium - Wikipedia](http://en.wikipedia.org/wiki/Amoeba_dubia) …“Amoeba Dubya”? I _knew_ it. ---
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [November 21, 2008, 1:44pm UTC](https://boards.straightdope.com/t/how-many-macroscopic-naked-eye-visible-single-celled-beings-are-there/473807/5 "2008-11-21T13:44:31Z")
> [@Der\_Trihs](#): > > There’s a type of algae that is single celled but quite large; I found a [mention](http://bio.classes.ucsc.edu/bio170/oldsite/C.fragile/Morphology.html) of it growing to 10 meters in size. It has many cell nuclei, but no internal cell walls. Bah. How come I didn’t predict the existence of things with multiple nuclei but no internal cell walls? I know: Because I’m not absolutely nuts! OK, I guess both that and [_Chaos_](http://en.wikipedia.org/wiki/Chaos_(amoeba)) are out, despite the fact [_Chaos_](http://www.bms.ed.ac.uk/research/others/smaciver/chaos.htm) (Seriously? Are all microbiologists D&D fans?) will now haunt my dreams. > [@Wiltshire](#): > > How rude. What have those slime molds ever done to you? Looked like Steve Ballmer. > [@](#): > > Hm, _codium fragile_ seems hard to beat, though it feels a bit like cheating. How’s this: [Acetabularia - Wikipedia](http://en.wikipedia.org/wiki/Acetabularia), single nucleus, up to 10 cm. This qualifies and is really cool. One nucleus == one cell, unless there is no nucleus at all. (Do any prokaryotes get this big?) Even biologists apparently call the multi-nucleus monsters ‘acellular’. > [@](#): > > Browsing around a little, there appear to be quite a few of lesser giants. > [http://www.glerl.noaa.gov/seagrant/GLWL/Algae/Chrysophyta/Cards/Botrydium.html](http://www.glerl.noaa.gov/seagrant/GLWL/Algae/Chrysophyta/Cards/Botrydium.html) > [Polychaos dubium - Wikipedia](http://en.wikipedia.org/wiki/Amoeba_dubia) Amazing. Absolutely amazing. ---
**Author:** ![Henrichek](https://avatars.discourse-cdn.com/v4/letter/h/5daacb/32.png) [@Henrichek](https://boards.straightdope.com/u/Henrichek)\ **Post date:** [November 21, 2008, 2:13pm UTC](https://boards.straightdope.com/t/how-many-macroscopic-naked-eye-visible-single-celled-beings-are-there/473807/6 "2008-11-21T14:13:20Z")
The largest bacterium seems to be the [Thiomargarita namibiensis](http://en.wikipedia.org/wiki/Thiomargarita_namibiensis), which can be up to 0.75 mm wide, and visible to the naked eye. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [November 21, 2008, 2:15pm UTC](https://boards.straightdope.com/t/how-many-macroscopic-naked-eye-visible-single-celled-beings-are-there/473807/7 "2008-11-21T14:15:00Z")
Ostrich egg? ---
**Author:** ![Zsofia](https://avatars.discourse-cdn.com/v4/letter/z/7bcc69/32.png) [@Zsofia](https://boards.straightdope.com/u/Zsofia)\ **Post date:** [November 21, 2008, 2:20pm UTC](https://boards.straightdope.com/t/how-many-macroscopic-naked-eye-visible-single-celled-beings-are-there/473807/8 "2008-11-21T14:20:59Z")
Why do most of these articles not have a picture, considering the size of the organism is the interesting feature? Especially a picture with a size reference? And not a little legend, but a dime or something? Sigh. Scientists are bad at people. ---
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [November 21, 2008, 2:33pm UTC](https://boards.straightdope.com/t/how-many-macroscopic-naked-eye-visible-single-celled-beings-are-there/473807/9 "2008-11-21T14:33:04Z")
> [@beowulff](#): > > Ostrich egg? Bah! I forgot that eggs technically qualify as single cell. OK, the biggest current egg has been mentioned. Let’s not list off dinosaur eggs or what blue whales produce when they menstruate, OK? > [@Zsofia](#): > > Why do most of these articles not have a picture, considering the size of the organism is the interesting feature? Especially a picture with a size reference? And not a little legend, but a dime or something? Sigh. Scientists are bad at people. [MicrobeWiki likes pictures.](http://microbewiki.kenyon.edu/index.php/Haloquadra) [Here is a page on the _Epulopiscium_, with an interesting depiction of its unusual life cycle.](http://microbewiki.kenyon.edu/index.php/Epulopiscium) As for scale, well, the vast majority of single-celled beings consider a drop of water the Ocean Sea. It’s impossible to provide a human scale for them. ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [November 21, 2008, 3:08pm UTC](https://boards.straightdope.com/t/how-many-macroscopic-naked-eye-visible-single-celled-beings-are-there/473807/10 "2008-11-21T15:08:50Z")
I’m confused by the article linked to in the OP. It seems to be saying the featured organism is an amazing new discovery that should change the way we understand the precambrian era. But then it says at the very end that they already knew about this organism, and what’s new is just that they found it in the Bahamas. And in this thread, we’re seeing that people have known about other, similarly huge single-cellers for a while. So what’s with the hype in the article? -FrL- ---
**Author:** ![Spectralist](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Spectralist](https://boards.straightdope.com/u/Spectralist)\ **Post date:** [November 21, 2008, 3:23pm UTC](https://boards.straightdope.com/t/how-many-macroscopic-naked-eye-visible-single-celled-beings-are-there/473807/11 "2008-11-21T15:23:15Z")
I think it’s that they didn’t know it left tracks like it does. And had previously attributed such tracks to multicellular organisms. ---
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [November 21, 2008, 3:46pm UTC](https://boards.straightdope.com/t/how-many-macroscopic-naked-eye-visible-single-celled-beings-are-there/473807/12 "2008-11-21T15:46:36Z")
> [@Frylock](#): > > So what’s with the hype in the article? It’s because we used to think only worms could have left the kinds of fossil tracks we’ve seen in really old rocks. Now that we know really big single-celled beings could have, it revises what we thought we knew about life back then. ---
**Author:** ![bouv](https://avatars.discourse-cdn.com/v4/letter/b/bc8723/32.png) [@bouv](https://boards.straightdope.com/u/bouv)\ **Post date:** [November 21, 2008, 4:05pm UTC](https://boards.straightdope.com/t/how-many-macroscopic-naked-eye-visible-single-celled-beings-are-there/473807/13 "2008-11-21T16:05:21Z")
> [@Derleth](#): > > Bah. How come I didn’t predict the existence of things with multiple nuclei but no internal cell walls? I know: Because I’m not absolutely nuts! You know your skeletal muscle cells have multiple nuclei, right? Squid giant axons are _huge_…compared to other axons, that is. They are between 0.5 and 1mm wide. The funny thing is, we usually associate nerves are conduction information very fast, using electrical signals and all. But the squid axon in unmyelinated, and has a conduction velocity of only 25m/s. ---
**Author:** ![Hello\_Again](https://avatars.discourse-cdn.com/v4/letter/h/85e7bf/32.png) [@Hello\_Again](https://boards.straightdope.com/u/Hello_Again)\ **Post date:** [November 21, 2008, 4:55pm UTC](https://boards.straightdope.com/t/how-many-macroscopic-naked-eye-visible-single-celled-beings-are-there/473807/14 "2008-11-21T16:55:51Z")
Some Amoeba can get big enough to be visible to the naked eye. - _Pelomyxa palustris_ can get to 5mm. ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [November 21, 2008, 5:02pm UTC](https://boards.straightdope.com/t/how-many-macroscopic-naked-eye-visible-single-celled-beings-are-there/473807/15 "2008-11-21T17:02:06Z")
> [@Derleth](#): > > It’s because we used to think only worms could have left the kinds of fossil tracks we’ve seen in really old rocks. Now that we know really big single-celled beings could have, it revises what we thought we knew about life back then. I see that now. I guess it just never occured to people that they would leave tracks until they actually saw them. -FrL- ---
**Author:** ![Neidhart](https://avatars.discourse-cdn.com/v4/letter/n/bbe5ce/32.png) [@Neidhart](https://boards.straightdope.com/u/Neidhart)\ **Post date:** [October 24, 2010, 12:45pm UTC](https://boards.straightdope.com/t/how-many-macroscopic-naked-eye-visible-single-celled-beings-are-there/473807/16 "2010-10-24T12:45:37Z")
I want one of these as a pet! ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [October 24, 2010, 2:37pm UTC](https://boards.straightdope.com/t/how-many-macroscopic-naked-eye-visible-single-celled-beings-are-there/473807/17 "2010-10-24T14:37:20Z")
A single celled zombie pet? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 24, 2010, 9:13pm UTC](https://boards.straightdope.com/t/how-many-macroscopic-naked-eye-visible-single-celled-beings-are-there/473807/18 "2010-10-24T21:13:40Z")
> [@](#): > > Bah! I forgot that eggs technically qualify as single cell. OK, the biggest current egg has been mentioned. Let’s not list off dinosaur eggs or what blue whales produce when they menstruate, OK? While we’re at it, human ova are also barely visible to the naked eye, if you’ve got sharp vision. “Naked-eye visible” is not as strict a criterion as you might think. ---
**Author:** ![falcotron](https://avatars.discourse-cdn.com/v4/letter/f/3ab097/32.png) [@falcotron](https://boards.straightdope.com/u/falcotron)\ **Post date:** [October 24, 2010, 10:23pm UTC](https://boards.straightdope.com/t/how-many-macroscopic-naked-eye-visible-single-celled-beings-are-there/473807/19 "2010-10-24T22:23:47Z")
> [@Derleth](#): > > OK, I guess both that and [_Chaos_](http://en.wikipedia.org/wiki/Chaos_(amoeba)) are out, despite the fact [_Chaos_](http://www.bms.ed.ac.uk/research/others/smaciver/chaos.htm) (Seriously? Are all microbiologists D&D fans?) will now haunt my dreams. Does the genus have three species called Chaos agatho, Chaos [I’m not sure how to say neutral], and Chaos kako? ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [October 24, 2010, 10:43pm UTC](https://boards.straightdope.com/t/how-many-macroscopic-naked-eye-visible-single-celled-beings-are-there/473807/20 "2010-10-24T22:43:05Z")
[Siphonous green algae](http://everything2.com/title/siphonous+green+algae) > [@](#): > > Siphonous green algae are actually enormous single cells which can grow to a meter in length or more. They are the largest unicellular organisms on earth, and have the largest single cell volume of any organism, squid neurons and ostrich eggs inclusive. [Next page](https://boards.straightdope.com/t/how-many-macroscopic-naked-eye-visible-single-celled-beings-are-there/473807.md?page=2)