Why the symmetry?

[Lucylu]

Apparently, the vast majority (somewhere around 97%) of species on Earth are invertebrates, and they can have either a radial symmetry (ie a wheel with spokes coming out from a central hub), typically without a brain or head as we would think of it, and typically living under water eg mussels.

OR they can have bilateral symmetry. The bilateral symmetry arises when the animal has to move about in search of food, whereas the radial symmetry is common when the animal/organism attaches itself to one place or moves about very, very slowly such as starfish. There are some types of sponges which are asymmetrical but as far as I know they have the monopoly.

Symmetry appears to be the most simple and most efficient form for movement in nature, which we have emulated in cars, planes, wheelchairs etc. We wouldn't dream of getting on a plane with one big wing and one little one! I presume that a being who is physically balanced can move the fastest and be most agile, evading predators, and hunting successfully.

Its also worth noting that any symmetry is only approximate.

-- Updated February 17th, 2016, 1:58 pm to add the following --

I think I got my sessile lifeforms mixed up there! Radial is for some sessile animals like anemones and coral (not mussels), floating animals such as jellyfish and very slow moving organisms such as starfish. Bilateral symmetry is for more dynamic, free movement.

[Steve3007]

Greta:

Hi Steve. Bin a while:)

I couldn't find the quote you meant but I agree. The Earth's radial symmetry and the various crystalline forms come to mind.

Hi Greta. Yes, it's been a while. I've actually set up a philosophy discussion group in my local pub. The real beer is better than virtual beer. But the real people are perhaps less colourful than some of the virtual people I've met here.

Anyway, I was also thinking of the fractal symmetry-across-scale of coastlines.

[ThamiorTheThinker]

This is a question I have been pondering and puzzling over for years now, but no one that I ask seems to have a fully justifiable and suitable answer. Research yields several different explanations, none of which are conclusive, so I ask you all.

Why are nearly all organisms on earth, mostly plants and animals, more or less bilaterally symmetrical? The left and right sides of each organism are basically the same, with very few exceptions. It seems that, with the process of evolution and the potential for asymmetrical advantages that lead to a large population of whatever organism, there would be far, far less unanimity amongst life forms. Why is this so?

I don't think this is a topic for a philosophy forum - even though philosophy is involved. Furthermore, philosophy of science doesn't entail that this forum is for any topic that is related to science - it is about the specific academic school of thought known as the "Philosophy of Science". This forum was intended to be the host of discussions about the implications and structure of science, as well as the effectiveness of induction, not about particular empirical observations.

I suppose I can respond to your question, anyway: Symmetry is common, statistically speaking. Molecules form in predictable and regular patterns, typically. Molecules bond and hold stable bonds in symmetric, geometric patterns (again, usually, though not always). Biology, then, being applied physics and chemistry, transitively carries this property.

Frankly, I don't know if that's a comprehensive answer. It may not even be true, but that's what I think based on my limited knowledge. I'm neither a chemist nor a biologist - I'm actually a student of physics. My ongoing education lies in mechanics, quantum and classical. If there are any biologists in this forum, I would love to receive their input.

[Sy Borg]

Greta:

Hi Steve. Bin a while:)

I couldn't find the quote you meant but I agree. The Earth's radial symmetry and the various crystalline forms come to mind.

Hi Greta. Yes, it's been a while. I've actually set up a philosophy discussion group in my local pub. The real beer is better than virtual beer. But the real people are perhaps less colourful than some of the virtual people I've met here.

Anyway, I was also thinking of the fractal symmetry-across-scale of coastlines.

I hadn't considered fractal symmetry, just the simpler forms.

Online groups draw from such a large number from so many different locales that's you'd expect diversity. I expect that face-to-face philosophy would be more polite with more trust in each others' judgement than online - even with beer involved.

I don't think this is a topic for a philosophy forum - even though philosophy is involved. Furthermore, philosophy of science doesn't entail that this forum is for any topic that is related to science - it is about the specific academic school of thought known as the "Philosophy of Science". This forum was intended to be the host of discussions about the implications and structure of science, as well as the effectiveness of induction, not about particular empirical observations.

I think that the phenomena in themselves carry philosophical content - at least for my mondo approach. What is it about the nature of reality and life that makes bilateral symmetry so advantageous for movement? It relates to the dimensions we live in; the possible planes of movement.

A thought: would we still have a front and a back if time was not an arrow moving forward but could move either way?

[ThamiorTheThinker]

Greta, what I was asserting is that "Philosophy of Science" is defined differently than how the original poster might have thought it was defined. I'm not arguing that there is no philosophical discussion to be had here, only that it does not fall under "Philosophy of Science".

To put it this way: Philosophy of science is a branch of philosophy concerned with the foundations, methods, and implications of science. The central questions of this study concern what qualifies as science, the reliability of scientific theories, and the ultimate purpose of science. (Dictionary definition)

-- Updated February 20th, 2016, 12:55 pm to add the following --

Greta, what I was asserting is that "Philosophy of Science" is defined differently than how the original poster might have thought it was defined. I'm not arguing that there is no philosophical discussion to be had here, only that it does not fall under "Philosophy of Science".

To put it this way: Philosophy of science is a branch of philosophy concerned with the foundations, methods, and implications of science. The central questions of this study concern what qualifies as science, the reliability of scientific theories, and the ultimate purpose of science. (Dictionary definition)

CORRECTION: I intended to write that this topic shouldn't be categorized under "Philosophy of Science" - I was not intending to write that it doesn't belong on the forum in general. The topic simply isn't categorized as "Philosophy of Science".

[Sy Borg]

Fair enough, Thamior. Yes, phenomenology rather than philosophy of science.

The bilateral symmetry arises when the animal has to move about in search of food, whereas the radial symmetry is common when the animal/organism attaches itself to one place or moves about very, very slowly such as starfish. There are some types of sponges which are asymmetrical but as far as I know they have the monopoly.

Almost all material online about sponges describes them as asymmetrical.



Yet I see bilateral symmetry here:


Radial symmetry in the Berry Sponge:


It appears that sponges are the only animals that can be asymmetrical, but not necessarily so.

[ThamiorTheThinker]

Adding to, though not extending the exact thoughts of my previous post, I would like to point out that our advanced brains often find significance in patterns where no significance actually lies. A graph of statistical data might have meaning in the mind of a person observing it even when no actual meaning resides inherently in the data.

Applying this mode of thought to biological evolutionary pathways, it is at least possible that evolutionary processes which produced varying modes of transportation in different organisms are interpreted by our brains as having significance. If you look at lines of evolutionary ancestry, you'll find that some families bear specific traits (such as quadrupedalism) because of the fact that they all emerged from a single ancestor species. This means that many species within that family share traits such as symmetry, or the lack thereof. It's not hard to imagine, then, that symmetry is just another product of evolution, just as forms of transportation such as quadrupedalism are.

[Paradigmer]

This is a question I have been pondering and puzzling over for years now, but no one that I ask seems to have a fully justifiable and suitable answer. Research yields several different explanations, none of which are conclusive, so I ask you all.

Why are nearly all organisms on earth, mostly plants and animals, more or less bilaterally symmetrical? The left and right sides of each organism are basically the same, with very few exceptions. It seems that, with the process of evolution and the potential for asymmetrical advantages that lead to a large population of whatever organism, there would be far, far less unanimity amongst life forms. Why is this so?

Mach's principle suggests all these organisms are undulated by the chirality structure of the cosmos.

Not only nearly all organisms on earth are more or less bilaterally symmetrical, all elements in microcosms that made up the organisms, are also bilaterally symmetrical. Chemically bonded compounds, also intrinsically demonstrated bilaterally symmetrical in their structures.

Life forms with freewill, supposedly undulated by the chirality structure of the cosmos, coalesced with the bilaterally symmetrical elements and compounds, therefore are physically imbued with the chirality characteristics, i.e. what you termed as bilaterally symmetrical.

Just my two cents.

[Rr6]

Fuller might say that since the Vector Equlibrium--- aka the cubo{6}-octa}8}hedron ---is the Operating System of Universe and it is asymmetrical i.e. it has 8 regular triangles and 6 regular squares.

The VE will contract with spin in two directions--- left or right --- on four differrent axes.
http://howthingsfly.si.edu/flight-dynam ... ch-and-yaw

The VE two possible spin contractions results in the icosa{20}hedrons surface being subdivided into the maxim set of 120 left-skew or right-skew, right triangles on surface of any sphere.

The equilateral triangle subdivides equally as 3 left-handed right triangles and 3 left-handed right-triangles.

The VE will transform into the only 3 regular symmetrical, structurally stable polyhedral of Universe;
1} icosa{20}hedron,
2} octa{8}hedron,
3} tetra{4}hedron.

Fuller would have us believe, all structure of Universe is based upon--- derived from ---these three polyhedra.

The VE's four bisecting hexagonal planes, share the same 60 degree configuration as that of the tetrahedron, only oriented differrently see link.
http://www.rwgrayprojects.com/synergeti ... ate31.html

Roger Penrose discovered quasi-periodic geometry patterns before they were discovered in nature.

Nature cannot exist in anyway that is not mathematically possible ie. all of nature/cosmos/Universe/God is complementary occupied space and metaphysical-1, geometric patterns.

We could say that, perhaps metaphysical-1, mind/intellect/concept ergo geometry can exist without occupied space, however, occupied space cannot exist with the complement of geometric patterns or other associated mathematics.

Even the macro-infinite, non-occupied space, that, embraces our finite, occupied space Universe, is has shape, because our finite, occupied space has a dynamic shape that shape the macro-infinite, from the inside > out, so-to-say. imho

r6

[Mattcbrrr90031]

I believe that the tool needed to understand "life" will be overlooked. Our entire understanding is based solely on the information received from light. Shape, size, geometry, math and science as a whole are only realized and computed by the transmission of light to your brain. Even at Cern it is the "bumps" in the symmetrical flow that allow the discovery of new particles which are then colour coated and graphed. However light is not symmetrical in the sense that it can be bent. So if we determine that discovering a unified theory is possible, would we not need the tools not bound by anything? This question was reinforced when the understanding of dark matter became apparent. If light does not interact with it, then how do we determine its existence and further our understanding. And then one day it all made sense to me. Like beautiful music unlike my ears have ever heard.

[Anthony Edgar]

This is an easy question to answer - God likes the symmetrical look.

[TSBU]

This is a question I have been pondering and puzzling over for years now, but no one that I ask seems to have a fully justifiable and suitable answer. Research yields several different explanations, none of which are conclusive, so I ask you all.

Why are nearly all organisms on earth, mostly plants and animals, more or less bilaterally symmetrical? The left and right sides of each organism are basically the same, with very few exceptions. It seems that, with the process of evolution and the potential for asymmetrical advantages that lead to a large population of whatever organism, there would be far, far less unanimity amongst life forms. Why is this so?

There is no need to a "why", when you ask a why, causes may be explained till the big band. Why am I writing this? because mi fparents decided to have kids.
But maybe this is enough for you:
It's better to have two eyes, two arms, two legs, you can see that with no explanation. Well, it's easier to make code for one part of the body and then duplicate this part for the other side, that's why many things are symetricall. Also, it has some advantages, symetricall things are better moving, a symetricall fish is faster, if your weigh and body is not similarr to both sides of your body, then you are going to fall, or you are going to waste energy in compensate that, etc.

-- Updated October 12th, 2016, 3:49 am to add the following --

Big bang* XD

[Paradigmer]

This is a question I have been pondering and puzzling over for years now, but no one that I ask seems to have a fully justifiable and suitable answer. Research yields several different explanations, none of which are conclusive, so I ask you all.

Why are nearly all organisms on earth, mostly plants and animals, more or less bilaterally symmetrical? The left and right sides of each organism are basically the same, with very few exceptions. It seems that, with the process of evolution and the potential for asymmetrical advantages that lead to a large population of whatever organism, there would be far, far less unanimity amongst life forms. Why is this so?

In my research on natural vortical phenomena, I noticed all naturally manifested structures, as well as organisms, are linked to an undulating vortex mechanism that could render their bilaterally symmetrical structures.

You might want to explore a treatise in my website on "Unisonal evolution mechanism". Towards the bottom of the web page, it briefly touches on the bilaterally symmetrical structures of some organisms. Hope this could offer you some useful inputs. Best to you.

[ThamiorTheThinker]

This is an easy question to answer - God likes the symmetrical look.

Nothing in philosophy is that easy. If you're going to defend this view, try giving some arguments and evidence to support your claim. I'd be very interested to know why you think God has something to do with the symmetry of biological forms and celestial objects.

[Anthony Edgar]

This is an easy question to answer - God likes the symmetrical look.

Nothing in philosophy is that easy. If you're going to defend this view, try giving some arguments and evidence to support your claim. I'd be very interested to know why you think God has something to do with the symmetry of biological forms and celestial objects.

Many creatures are outwardly symmetrical and many aren't.  Regarding the creatures that are, I find it interesting that most of their inner parts aren't symmetrical; it's as if their outward appearance is important for some reason. 
If a creature that is symmetrical loses a limb, they lose their symmetry and we find the sight of them distasteful.  The loss of symmetry somehow offends our sense of beauty.  Why should that be?  Other than its role in sexual attraction, evolution can't explain why humans appreciate beauty, or why symmetry should be a prerequisite for beauty.  

I would argue that it's no coincidence that most, if nor all, creatures we find beautiful are symmetrical in shape.  I would also argue that human beings are programmed to appreciate beauty, since we are made in God's image (Genesis 1:26) and God is the Author of beauty.
 
It's remarkable that symmetry is evident across such a wide spectrum of creatures - mammals, reptiles, fish, birds, insects, crustaceans.  Symmetry is synonymous with beauty, and beauty for the sake of beauty points to, not evolution, but design.  The Designer is obviously a big fan of symmetry.