Animal Symmetry (The Mathematics of Symmetry (A butterfly has mirror…
The Mathematics of Symmetry
A butterfly has mirror images on each wing.
A butterfly has two halves.
This balanced arrangement of parts is called symmetry, is characteristics of many animals.
A butterflies symmetry contributes to its appearance.
The balanced wing helps butterflies fly easier.
Animals have different types of symmetry.
In certain types of symmetry you can draw a line down the center of the figure.
This is called a line of symmetry.
An object has bilateral symmetry if there is a line that divides it into halves that are mirror images.
Radial symmetry have many lines of symmetry that go through a central point.
Some animals have no symmetry, like sponges.
Symmetry and Daily Life
Animals without symmetry tend to have simple body plans.
Animals with bilateral or radial symmetry have complex body plans.
Depending on their symmetry, animals share some characteristics.
Animals With Radial Symmetry
The outside parts of animals with radial symmetry are equally spaced around a center point.
Because of the circular arrangement in animals with radial symmetry, those animals don't have a front or back end.
Animals with radial symmetry have things in common.
All of them live in water.
Most of them don't move very fast, they stay in one spot.
They are moved through the water by the currents, or they creep across the bottom.
Animals With Bilateral Symmetry
Humans have bilateral symmetry.
In general, animals with bilateral symmetry are larger and more complex than animals with radial symmetry.
Animals with bilateral symmetry have a front end that typically goes first.
Those animals move more quickly than animals with radial symmetry.
This is partly because bilateral symmetry allows a streamlined body.
Animals with bilateral symmetry have have a better sense of the organs in their front that get information about what is in front of them.
Sense organs help with finding what is in front of the animal.
For example, a tiger has eyes, whiskers and more on its head.