The evolutionary explanation is that it rarely has an advantage to be asymmetrical.If your left leg would be longer than your right leg, for example, you would run out of Mank. And it’s a “natural” aesthetic that we find symmetrical faces more beautiful than asymmetric faces. After all, asymmetry may be caused by an injury or infection in a part of the face. People with symmetrical faces therefore have more partner choice and therefore get more and/or healthier children. The same applies to many other animals.
In addition, if symmetry has no major disadvantages, it is the default because it is genetically and embryonally cheaper to build a symmetrical body.Because to encode the recipe for building a symmetrical body in the DNA, you only have to describe half of the body. Thus, an asymmetrical body would require a larger genome, which requires more DNA production, and a greater chance of something going wrong.
Where asymmetry has a great advantage, for example in the structure of the heart and the digestive system, we are indeed asymmetrical.But there must be a good reason. Machine Builders, furniture builders etc also choose symmetry if there is no good reason not to do it. For about the same reasons.
Yet the above argument is not convincing, and we need to think deeper about it.There is a very interesting book written on this subject: Right hand, Left hand.The book explains why it is very difficult to describe an asymmetrical body in the DNA. He starts with this thought experiment:
Imagine coming into radio contact with an alien civilization.You talk to them about things you have in common, like math and the raw materials. There is, however, a game rule: you may not refer to things that the extraterrors can also see, such as specific star images. Only to universal knowledge.
You can explain to the extraterrors what you know in “future” and “past”.”Above” and “down” is also successful. But “left” and “right”? You may be able to explain what the left/right dialektics mean, but you cannot distinguish “left” from “right”. You could choose one of them to name “Glubs” and the other “zluchts”, but you can not explain which of the two links it is. If you send a building plan of an asymmetrical object to the extraterreders, you have no guarantee that they will build it as you consider. It may well be that they build the mirror image of it.
Developing an embryo has the same problem.A symmetrical uterus can build asymmetric structures, but for each component there is 50% chance of getting a mirror image. An asymmetrical body therefore has a very high risk of birth defects.
The book then questions the question: how can it be that we still have asymmetric organs, and indeed, that there is not 50/50 chance to be left-handed, or to have a right heart?Very early in the evolution there is “chosen” for D glucose instead of L glucose. This will have an impact on the direction with which DNA is running, and many other biochemical structures. On another planet it could be the other way around. Or maybe not. There are indications in the particles physically that there is a subtle difference between left and right. Whether this difference is too subtle to influence the evolutionary “choice” between link and right-rotating molecules is not entirely clear. At least, when the book was written.
There is an awful lot of symmetry in nature.
This has everything to do with “the golden ratio”.
Also called “The divine Relationship” by many.
For the mathematical explanation, I refer to Google.
One theory is that everything strives to grow as strongly as possible.
But more interesting is the theory of beauty.
Artists discovered that using the golden ratio in BV. paintings, much nicer and better art.
In any case a fantastic phenomenon!
I think that is a very good question.
Symmetry is aesthetically sound.
Something that is only one side is not actually there.
But I think nature is less symmetrical than is thought.
The things, which are not symmetrical in nature (trees, for example), contain things that can be symmetrical (but not need to), such as leaves.And both humans and animals generally have two eyes, two ears, two nostrils, one (multiple of) two limbs, and so on. Then it quickly seems symmetrical.
A face also seems symmetrical.But if you split a face from top to bottom (vertically so) into two parts and you mirror a part, which you put instead of the other part next to it, then you see differences anyway.
Also the leaves on a tree appear symmetrical.Yet they are not. In my opinion, there is no leaf that the ‘ veins ‘ have been sitting right next to each other.
So I really wonder to what extent nature is so symmetrical…
In The documentary called ‘ The Code ‘ it is told that symmetry costs the least energy, and the easiest is to make.Therefore, everything and everyone follows at the molecular level (or even smaller or larger) this method.
Robbert Dijkgraaf: “from snowflakes to starfish, from architecture to music, from our own mirror image to the smallest particles: nature and culture is determined by symmetry, perhaps the most powerful wetness in science.This centuries-long discovery tour leads past the ancient Greeks, French revolutionaries, Islamic wall decorations and Chinese nuclear physicists. “
Is that so?I would look in the mirror and cover the one face-down alternately. Don’t scare!
In my opinion, almost nothing is symmetrical in nature.There is still apparent symmetry.
But there is no grass blade the same.There is no snowflake the same.
I myself have not quite a lot of DNA and molecular biology, but the DNA code is only a recipe for proteins and not a building plan for the body.
I do not know what the construction plan is, but it has to do with the embryonic development of organisms.
All organisms are basically symetrical because cells follow a certain ranking during embryonic development and the only way to be in a system where further no higher inteligation is involved in order to organize cells themselves is by Strict Symetry.
You can also see this in crystals, molenculen and snowflakes all these systems rank themselves according to strict Symetry.
That is what is called perfection.