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FireMadeFlesh's avatar

What is the simplest organism that is said to have a brain?

Asked by FireMadeFlesh (16548points) March 4th, 2010

Are there some organisms that have a rudimentary neural network that isn’t necessarily classed as a brain? Do all species of animal have a brain?

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35 Answers

TheLoneMonk's avatar

edited by me because my wee wee is less simple than I gave myself credit for

AstroChuck's avatar

Probably the fairyfly. It’s a tiny variety of wasp.

Cruiser's avatar

My MIL AKA Kathy

cockswain's avatar

@dpworkin Where is a worm’s brain located? Can’t you cut off either end and it the largest segment survives? Freakish.

dpworkin's avatar

Oh, no! Not Dualism again!

FireMadeFlesh's avatar

@cockswain An octopus is thought to have brains in each tentacle, since each tentacle is capable of regrowing a new head and the additional tentacles. Maybe a worm has a brain at both ends.

@AstroChuck Good one, I hadn’t thought in that direction.

nikipedia's avatar

Great question. The gray area between “brain” and “rudimentary neural network” is occupied by lower invertebrates.

As @dpworkin pointed out, worms and other lower-order bilateria have two nerve cords that run along the length of the body from the anus to the mouth.

Members of the phylum Cnidaria (like jellyfish) have diffuse nerve nets and no central nervous system.

Arthropods have a slightly more sophisticated system of nerves bundled together into ganglia and a rudimentary spine.

Above that, I think they all count as brains.

dpworkin's avatar

He’s lower than a worm, which leads to a paradox.

keobooks's avatar

Glen Beck has a nerve cord that runs from anus to mouth. Sometimes, it malfunctions and he excretes waste from his mouth and speaks from his anus. And this is how most talk radio is made.

FireMadeFlesh's avatar

GA @nikipedia, that pretty much answers it.

PacificRimjob's avatar

Attorney General Eric Holder.

Racist, unAmerican, incompetent.

dpworkin's avatar

I don’t know why I bother, but can you give one documented example of just one racist, or un-American, or incompetent act of his? Doesn’t have to be all three, because that we all know is untrue, even you. Just one. With a real source, not Glen Beck or Anne Coulter. Put up or shut up.

cockswain's avatar

@PacificRimjob You tell some pretty good one-liner jokes sometimes. Stick with those.

phoenyx's avatar

removed by me

FireMadeFlesh's avatar

@phoenyx They are definitely simple, but I can’t find anything on their neural structure. Do know what their nervous system is like?

How did my question suddenly become about American politics?

dpworkin's avatar

So now we know. You’ve got nothin’. Now shut up and let the grown-ups enjoy Fluther.

PacificRimjob's avatar

Because you said so @dpworkin?

cockswain's avatar

@PacificRimjob None of those sources support your argument. Celebrifi will not be regarding by intelligent people as a credible source, nor is a simple blog. You might as well have written the blog yourself. You spout Fox News rhetoric anyone could regurgitate without reflection. Present both sides to show you are knowledgeable and people will believe you are informed and respect your opinion more.

PacificRimjob's avatar

Fox News?

Impossible, I don’t watch Fox News.

Respect my opinion more? Don’t make assumptions regarding my objective.

“Now shut up and let the grown-ups enjoy Fluther.” Ironic, but not funny.

cockswain's avatar

Your sources do.

dpworkin's avatar

The offer is still open. One example from one credible source and I will apologize. But you need to think about what credible means. Maybe you should look it up.

cockswain's avatar

My goal isn’t to belittle you. In the past I accepted poor sources as fact and learned from it. Be very careful what you think is fact.

PacificRimjob's avatar

“Credible” means a source your approve of.

This exchange is now futile.

@cockswain : noted and thanks.

dpworkin's avatar

“Credible” just means factual and unbiased. Since it was a lie, there is no such source. You failed to put up, now it’s time to shut up. All you do is to continue to discredit yourself when you can’t substantiate your claims.

PacificRimjob's avatar

I saw and heard Holder’s inapropriate inaugural statement on television live. You can accuse me of hallucinating if you wish.

Who is arguing that holder intends to ‘civilianize’ the terror trials?

phoenyx's avatar

@FireMadeFlesh I’ll just send you a PM so I can skip all of this ^

augustlan's avatar

[mod says] Let’s get back to the actual topic, folks. Thanks!

Response moderated
JeffVader's avatar

….... Umm, Texans!

mattbrowne's avatar

Some primitive animals just have a decentralized nervous system. Earthworms for example lack a brain but have nerve centers (called ganglia). They also lack eyes but can sense light with photoreceptors. Roundworms have a simple brain and nervous system consisting of approximately 300 neurons. The brain of an insect consists of a ganglion in the head. There’s more useful information here:

http://www.scienceclarified.com/Bi-Ca/Brain.html

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