Are lifeforms always symmetrical in nature?

Question

(with exemption to amoebas)

Answer 1

all the higher animals display symmetry if form and function.
symmetry is the manifestation of balance. balance promotes life.the nature tends towards entropy and living organisms fight that entropy or randomness to maintain form and structure.

The body plans of most multicellular organisms exhibit some form of symmetry, either radial symmetry or bilateral symmetry. A small minority exhibit no symmetry

Radial symmetry


These organisms resemble a pie where several cutting planes produce roughly identical pieces. An organism with radial symmetry exhibits no left or right sides. They have a top and a bottom (dorsal and ventral surface) only.

Animals
Most radially symmetric animals are symmetrical about an axis extending from the center of the oral surface, which contains the mouth, to the center of the opposite, or aboral, end. This type of symmetry is especially suitable for sessile animals such as the sea anemone, floating animals such as jellyfish, and slow moving organisms such as starfish (see special forms of radial symmetry). Animals in the phyla cnidaria and echinodermata exhibit radial symmetry. Cnidarians are one of the simplest life forms on this planet.


Plants
Many flowers are radially symmetric (also known as actinomorphic). Roughly identical petals, sepals, and stamen occur at regular intervals around the center of the flower.

Bilateral symmetry

Bilateral symmetryIn bilateral symmetry (also called plane symmetry), only one plane, called the sagittal plane, will divide an organism into roughly mirror image halves (with respect to external appearance only, see situs solitus). Thus there is approximate reflection symmetry. Often the two halves can meaningfully be referred to as the right and left halves, e.g. in the case of an animal with a main direction of motion in the plane of symmetry.

humans are bilaterally symmetrical and be cut into two identical halves along the saggital plane.

Answer 2

Bilateral Symmetry In Nature

Answer 3

starfish have radial symmetry. i think we find that symmetry is a common principle but with exceptions or not absolute in the details. for instance, in almost all people the heart and spleen are on the left side and the liver on the right. the fiddler crab is known for having one large claw and one small claw. the process by which asymmetry occurs is actually very interesting, especially where a person has a right-sided heart as in kartagener syndrome. check the link below for more information.

Answer 4

Yes, symmetry, biological, similarity or balance between parts of an organism so that when a straight cut is made through a point or along a line, equal, mirror-image halves are formed. Symmetry in body shapes is related to the lifestyles of organisms. Asymmetry, or the absence of symmetry, most often occurs in sessile organisms or in slow-moving forms such as amebas. Most other organisms can generally be classified in three groups with respect to symmetry type.
In spherical, or point, symmetry, any straight cut through the central point of a sphere divides it into mirror-image halves. Point symmetry, often called universal symmetry by biologists, is seen in some floating animals with radiating parts, such as the single-celled protozoans of the order Radiolaria.

Radial, or line, symmetry, as exemplified by a cone or a disk that is symmetrical about a central axis, is especially suitable for sessile or floating animals. Most radially symmetrical animals are symmetrical about an axis extending from the center of the oral surface, which contains the mouth, to the center of the opposite, or aboral, end. Radial symmetry is seen in sessile organisms such as the sea anemone, floating organisms such as jellyfish, and slow-moving organisms such as sea stars, or starfish. Many jellyfish have four radial canals and are said to have tetramerous radial symmetry; sea stars, with five arms, have pentamerous radial symmetry. Many flowers, such as dandelions and daffodils, are radially symmetrical. Nonradial parts, such as the slit-shaped gullets of sea anemones, are often present in otherwise radial animals.

In plane, or bilateral, symmetry, one particular plane, termed the sagittal plane, divides the body into two equal halves, usually right and left halves that are mirror images of each other. Flowers such as orchids and sweet peas are bilaterally symmetrical. Bilateral symmetry is most suitable for actively moving organisms, as it permits streamlining, and is the most common symmetry among animals. In animals this symmetry type also favors the formation of main nerve centers and special sense organs and contributes to cephalization, or the evolutionary development of a head.

Answer 5

Starfish are in fact symmetrical. . .what is called radial symmetry, whereby one just cuts across the diameter of the plant or critter, and the two halves match.

Symmetry is the general rule in nature, whether bilateral (as in most animals) or radial.

Answer 6

no! i suppose most species are since there is a heck load of insects and they are bilaterialy symmetrical.also plathyhelminthes(flatworms), annelids,
arthropods(includes insects),chordates are all bilaterally symmetrical.
but there are some exeptions for example sponges and sea anemones are asymetrical. meanwhile starfish and other cnidarians are radially symmetrical.
however i don't think a single-celled organism can possibly have symmetry.

Answer 7

No!

Internally:
The human heart is on the left, not in the middle.
The layout of your vital organs is not symmetric.
The left half of your brain is different to the right half.

Even if you only meant "externally", your counterexample is the starfish.

Answer 8

Not at all. Starfish with five legs are not symmetrical. There are others as well....

Answer 9

yes

Answer 10

yes