Asymmetry

Lecture

Asymmetry (Ancient Greek ασυμμετρία literally «disproportion» from μετρέω «I measure») — the absence or violation of symmetry. Most often the term is used in relation to visual objects and in the visual arts. In artistic creation, asymmetry can serve (and very often does serve) as one of the main means of form-building (or composition). One of the concepts close to it in art is arrhythmia.

In living nature

Due to the constant division of cells in an organism, asymmetry in organisms is a common phenomenon at least in one dimension alongside biological symmetry (see also Interhemispheric asymmetry).

Louis Pasteur believed that biological molecules are asymmetric because of cosmic [i.e., physical] forces that control their formation, imparting properties (asymmetry) similar to their own. Although in his time, and even now, greater significance is attached to symmetry in physical processes, fundamental physical asymmetries are also known, starting with time.

Usefulness for organisms

Hand dominance — asymmetry in the development of skills in people and animals. Training of neural pathways while learning a skill with one hand (paw) takes less time than the same training with both.

Fiddler crab, Uca pugnax

Flounder

Nature also provides several examples of chirality in traits that are usually symmetric. Below are examples of animals with clear signs of left-right body asymmetry:

Fiddler crabs have one large claw and one small claw.
In narwhals, the tusk grows from the left incisor, can reach 10 feet, and forms a spiral.
The flounder has evolved to always swim with one side up, as a result of which it has both eyes on one side.
Some species of owls have asymmetry in the size and placement of their ears, believed to help them locate prey.
In many male animals (from insects to mammals), the genitalia are asymmetric. Why evolution required this remains, in most cases, a mystery to this day.

The phylum Porifera consists of sponges, made up of several species, which display an almost complete absence of body symmetry. Instead, they evolved to make maximal use of water flow through their central cavity.

As an indicator of unfitness

Certain disturbances in the course of an organism's development, resulting in congenital defects.
Injuries after cell division that cannot be biologically repaired, such as loss of a limb during an accident.

Since congenital defects and injuries most likely indicate poor health of the organism, defects leading to asymmetry often put the animal at a disadvantage when it comes to finding a mate. In particular, the degree of facial symmetry in humans is linked to physical attractiveness, but complete symmetry is impossible and probably unattractive.

In mathematics and other sciences

Coefficient of skewness — a characteristic of the distribution of a random variable.
Asymmetric relation — an antireflexive and antisymmetric binary relation.
Asymmetric atom — a concept in stereochemistry.
Asymmetric cryptography — public-key encryption.
Asymmetric federation — a form of state structure characterized by differing status among the federation's constituent subjects.
Baryon asymmetry of the universe
Ohmic asymmetry — the difference in resistance between the conductors of a pair in a multi-pair cable.
Capacitive asymmetry — the difference in capacitance between the conductors of a pair in a multi-pair cable.

In architecture

In architectural styles preceding the modern era, emphasis was generally placed on symmetry, except when siting under extreme conditions or historical developments forced a departure from classical ideals. In contrast, some contemporary architects have become much freer in their use of asymmetry.

While most bridges use a symmetric form for simplicity of design, analysis, fabrication, and economy of material use, a number of modern bridges have deliberately departed from this, either in response to the demands of a particular site or in order to create a striking design.

Some structures that use the idea of asymmetry