Naked Science Forum
Life Sciences => Plant Sciences, Zoology & Evolution => Topic started by: thedoc on 16/09/2015 16:50:01
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John Gamel asked the Naked Scientists:
The vast majority of animals are symmetrical - i.e., the left sides of their bodies are mirror images of the right sides. Of course very few if any are symmetrical when it comes to internal organs. Also, I've read that some crabs have one claw much larger than the other. So what is the most asymmetrical living animal on the planet - excluding, of course, congenital defects?
What do you think?
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The flounder immediately comes to mind, depending on how you look at it. I can't really think of any others off the top of my head. It's interesting that you mention crabs. I'd always noticed the asymmetry but hadn't really consciously thought of it until now.
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How about the amoeba (https://en.wikipedia.org/wiki/Amoeba_proteus)? It's shape is continually changing due to cues in its environment.
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Yeah, the amoeba would probably be the best answer. Nice thinking, I wasn't thinking outside the multicellular box.
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It has occurred to me, while soaping down Mistress Olivia's back, that sponges have no symmetry whatsoever.
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They have a roughly cylindrical symmetry. As such they have a higher degree of symmetry that you , me or a starfish.
However, at a molecular level, no life form on earth is symmetrical. The amino acids, sugars, DNA etc which we are made from are all unsymmetrical- they can't be superimposed on their mirror images.
https://en.wikipedia.org/wiki/Chirality
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There is symmetry and there is not symmetry.
There is no "rough" symmetry just as there is no roughly being heterosexual. There is straight, bi, gay, neuter, or good red herring..
If you do not speak precisely - outside of the quantum milieu - in science, well, that's the sort of unfortunate result of teaching science on television.
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There is symmetry and there is not symmetry.
There is no "rough" symmetry just as there is no roughly being heterosexual. There is straight, bi, gay, neuter, or good red herring..
If you do not speak precisely - outside of the quantum milieu - in science, well, that's the sort of unfortunate result of teaching science on television.
Don't be silly.
If there are no degrees of symmetry then the thread is meaningless but plenty of people have replied to it, so they understand that things can be more symmetrical than others.
Approximate symmetries are important in some areas of science like spectroscopy- they explain why some transitions are weak.
Also, as I pointed out, no life is actually symmetrical.
Also, if you are going to complain about people not speaking precisely, don't blame it on unrealistic things like teaching on television.
Nothing I do can be a result of teaching on television.
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The subject is symmetry not it's second cousin fuzzy transitions in spectroscopy.
The fact that many people have replied to an erroneous statement only constitutes "truth" among people who have learned logical rigor on the "telly".
There are symmetrical groups, but there are no degrees of symmetry. There is no transformation of the image of a sponge which reproduces the image. A geometric shape or object is symmetric if it can be divided into two or more identical pieces that are arranged in an organized fashion. Can you do that with the images I showed?
I learned about symmetry in the Physical Chemistry class, Stanislaus State College at Turlock, California. It is essential to understanding chirality,spectroscopy, and crystallograpy. Where did you learn your chemistry, Mister? Could you get a refund of the tuition?
I have replied directly to you, my argumentative, and foul-mouthed friend, because I thought it was more important to clear up your misinformation in front of the readers than my original intent to tell you to talk to the hand.
Having done that ..... talk to the hand.
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There is no transformation of the image of a sponge which reproduces the image.
An image of a sponge isn't a sponge. The yellow sponges in the image you posted appear to have rotational symmetry about their long axis.
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And yet another argumentative Big Noise from Winnetka [2.] chips in for the home team.
The Phylum Porifera
Etymology:- From the Latin porus for pore and Ferre to bear,
hence an animal with with pores.
Characteristics of Porifera:-
1)No definite symmetry. (my emphasis)
2)Body multicellular, few tissues, no organs.
3)Cells and tissues surround a water filled space but there is no true body cavity.
4)All are sessile, (live attached to something as an adult).
5)Reproduce sexually or asexually, sexual reproduction can be either gonochoristic or hermaphroditic.
6)Has no nervous system.
7)Has a distinct larval stage which is planktonic.
8)Lives in aquatic environments, mostly marine.
9)All are filter feeders.
10)Often have a skeleton of spicules. [1.]
When you want to try that on, you best have facts and not appearances there, Sparky
Because you can bet that I do.
[1.] http://www.earthlife.net/inverts/porifera.html
[ 2.]
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"The subject is symmetry not it's second cousin fuzzy transitions in spectroscopy."
And you moved the goalposts to whether or not roughly symmetrical things exist; so don't complain when people address that question.
"The fact that many people have replied to an erroneous statement only constitutes "truth" among people who have learned logical rigor on the "telly"."
No, the definitions of the meanings of words are essentially subordinate to common use. Logical rigour has nothing to do with it.
"There are symmetrical groups, but there are no degrees of symmetry."
Plainly wrong, a sphere has lots of symmetry operations that are lacking for ( for example) for a cube.
And a cube has symmetries that don't apply to a dog.
So there are obviously hierarchies of symmetries which are apparent to anyone who thinks about it.
"here is no transformation of the image of a sponge which reproduces the image. "
As has been pointed out, we were discussing the object, not its image. The object is essentially rotationally cylindrical.
"I have replied directly to you..."
and yet you say elsewhere that you don't do that. Is it your memory, or your logic that is at fault?
"because I thought it was more important to clear up your misinformation in front of the readers than my original intent to tell you to talk to the hand. " Oddly, that's pretty much the same reason that I'm posting.
"And yet another argumentative Big Noise from Winnetka [2.] chips in for the home team."
Nice attempt at passing off an appeal to authority as an argument there, but since those sponges clearly have rotational symmetry, not only is it a logical fallacy, but the "authority" is plainly wrong.
"1)No definite symmetry."
Nonsense, they plainly have rotational symmetry (at least to roughly the same extant that a starfish has).
Not that it matters but, re. "here did you learn your chemistry, Mister? "
https://en.wikipedia.org/wiki/Department_of_Chemistry,_University_of_Oxford#Overview
And I don't think I'm the one in need of a refund.
You also seem (as usual) to have missed the point.
You said "If you do not speak precisely - outside of the quantum milieu - in science, well, that's the sort of unfortunate result of teaching science on television.". That clearly does not make sense. I never taught science on television. Did you mean it's a problem arising from learning science from the television, or even that it arises from the poor teaching of science on television?
Do you realise that "If you do not speak precisely - outside of the quantum milieu - in science" you will be held to account for it if you berate other's precision or lack of it?
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I repeat ..
"A geometric shape or object is symmetric if it can be divided into two or more identical pieces that are arranged in an organized fashion. Can you do that with the images I showed?"
Apparently not.
All the smoke and mirrors -- all the sound and fury -- here has obscured that fact.
Oxford, eh?
I was taught how to put my case more strongly than that at Stanislaus State College, Turlock, California.
And they enrolled me straight out of the Army with no high school diploma - only a GED certificate - for $600/ semester.
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now hold on a minute.
There are many symmetry operations (reflection, rotation, improper rotation and inversion).
And one has to define the spatial and temporal resolution. For instance, imagine a spinning propeller. There are three blades equally spaced, so instantaneous symmetry must have some 3-fold rotational symmetry. But if you are near a spinning propeller, you may as well regard it as having a spinning disk of death which has cylindrical symmetry.
Similarly if we look very closely at objects, and account for their structure at a molecular scale, most of an object's symmetry vanishes unless it is a uniform crystalline object. However, it is still useful to identify the symmetries that, for example, a starfish almost has. Defining an overall symmetry and then a degree of disorder from that symmetry is very common and very useful.
If we consider the broad morphology of the sponge, it appears to be roughly cylindrical. Granted, it is not perfectly straight and has a very complex webbed structure. However, if we consider the human anatomy at the level of the webbed structure of the sponge, we don't appear to be symmetrical either. Never mind the placement of our heart, stomach, liver, pancreas etc.--just consider the web of capillaries and nerves that extends through our extremities. This web is of the same resolution as the sponge, and equally unsymmetrical on such a small scale.
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(1)I repeat ..
"A geometric shape or object is symmetric if it can be divided into two or more identical pieces that are arranged in an organized fashion. Can you do that with the images I showed?"
...
(2) I was taught how to put my case more strongly than that at Stanislaus State College, Turlock, California.
Re 1,
I see that you have repeated it.
Why did you do that? It has already been shown to be invalid because we were talking about the sponge itself, not the picture.
The sponge has rotational symmetry.
Re 2,
Then why don't you do so, rather than spouting nonsense and asking about education?
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The question of the most asymmetrical animal - which happens to be the matter at hand - depends upon a clear and rigorous definition of symmetry or everything else said is nonsense.
Symmetry is a mathematical abstract of reality...just like arithmetic...
Stop the music! Stop the music!
Mr. Evan_au Sir! Why do you let this snotty Oxonian clown pull an egg-sucking stunt like that and then erase my own measured (but justified) response... without having the decency to tell the readers what you have done?
Apparently the forum rules which you prattle on and on about are applied differently to Oxonians but we hoi polloi must submit to their ridicule and humiliations in meek silence.
Well Shuck you, Farly- you and your under-handed snotty "bored_chemist" Oxford, Pal I didn't start this, you pair of cowards.
Because I am the man who is about to teach you the you-don't-know-the-half-of-it-Buddy Blues.
Put'em up you asshats.
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The question of the most asymmetrical animal - which happens to be the matter at hand - depends upon a clear and rigorous definition of symmetry or everything else said is nonsense.
Fair point.
Now, we can rigorously apply your definition of symmetry, and find that no animal is really symmetrical.
Or we can actually understand the question as intended and provide helpful answers like the flounder.
Of course, if we take the former path, we can start filling up the thread with rubbish about who went to what college.
BTW, why do you feel this sort of thing
" this snotty Oxonian clown "
helps?
and re. "I didn't start this, you pair of cowards"
Yes you did.
You did it when you made this false assertion "There is no "rough" symmetry"
Others will have their own opinion on whether you did that as a deliberate attack on me personally.
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Still up to their shoddy tricks I see. I am posting this after they removed it. (Although I did instantiate one of my cyber golems to post it originally.) As you can see from this, it terrifies certain people. Anybody want to make a side bet on how often this stupidity is repeated? (Hint: golems are very easy to instantiate ..."ad nauseum" here )
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Well played, Oxford!
"Bored_Chemist" is many things, but a Clown? Funny?
Pecos_Bill wise up!
But I wonder why you (Bored_chemist ) find it your personal mission in life to follow him continually about and hector him?
This thread began on September 16th. It lay here peacefully until the 23rd when Pecos_Bill had the temerity to make his opinion known at 3 AM.
You, Sir, showed up at 9AM that day to contradict him after seven days in which you had not enough interest to speak at all.
This same behavior was seen in the notorious GCSE dogfight - now locked away as too radioactive to be entered anymore.
This is the sort of thing that gives people nightmares about nuclear weapons in England. You see what you precipitated here ... over an obscure point of biology.
Here are a pair of concepts for you to meditate upon.
1. Live and let live.
2. Mind your own damned business.
For as Rodney King said - As the smoke was clearing in the LA riots, "Can't we all just get along?"
ADDENDUM: Because if you keep this up one of us has to go. And they can't keep me out.
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Still up to their shoddy tricks I see. I am posting this after they removed it. (Although I did instantiate one of my cyber golems to post it originally.) As you can see from this, it terrifies certain people. Anybody want to make a side bet on how often this stupidity is repeated? (Hint: golems are very easy to instantiate ..."ad nauseum" here )
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Well played, Oxford!
"Bored_Chemist" is many things, but a Clown? Funny?
Pecos_Bill wise up!
But I wonder why you (Bored_chemist ) find it your personal mission in life to follow him continually about and hector him?
This thread began on September 16th. It lay here peacefully until the 23rd when Pecos_Bill had the temerity to make his opinion known at 3 AM.
You, Sir, showed up at 9AM that day to contradict him after seven days in which you had not enough interest to speak at all.
This same behavior was seen in the notorious GCSE dogfight - now locked away as too radioactive to be entered anymore.
This is the sort of thing that gives people nightmares about nuclear weapons in England. You see what you precipitated here ... over an obscure point of biology.
Here are a pair of concepts for you to meditate upon.
1. Live and let live.
2. Mind your own damned business.
For as Rodney King said - As the smoke was clearing in the LA riots, "Can't we all just get along?"
ADDENDUM: Because if you keep this up one of us has to go. And they can't keep me out.
Are you aware that the forum has an established policy for dealing with sockpuppets?
Have a look here
http://www.thenakedscientists.com/forum/index.php?topic=23210.msg254061#msg254061
And there's a very simple way to ensure that we get along.
Don't post stuff that's wrong.
If you do, and someone points it out, don't try to pretend you were right in the first place.
Yyu might also want to avoid spamming the whole forum with irrelevant dross.
And re. "But I wonder why you (Bored_chemist ) find it your personal mission in life to follow him continually about and hector him?"
Given that I'm noted for arguing with damned nigh anyone who posts trash here, you might want to read this
https://en.wikipedia.org/wiki/Persecutory_delusion