1. Another Difference Among Animals and Things By Mr. Guillen
SYMMETRY
Another Difference Among Animals and Things
By Mr. Guillen

2. What is symmetry in animals?
Symmetry is the way their body parts match up around a point or central line.
Body parts with symmetry match up as mirror images when they are folded over.

3. Symmetry is all around us
Symmetry exists all around us and many people see it as being a thing of beauty.
Line Symmetry exists in nature, but you may not have noticed.
You can find them in the air, under the sea, in land…

4. In the air. Is it symmetrical?
butterfly bat dragonfly
yes yes yes
Can you name other examples in the air?

5. Under the sea. Is it symmetrical?
sea star crab sea urchin
yes yes yes
Can you name other examples under the sea?

6. In land. Is it symmetrical?
deer spider
yes yes
Can you name other examples in land?

7. Animals without symmetry
There are animals without symmetry.
No matter how you fold a sponge its body parts do not match up.

8. Radial Symmetry
Is an animal that has body parts that extend outward from a central point, like a sea star.

9. Spherical Symmetry
An animal with a sphere-shaped body like the sea urchin has a spherical symmetry.
You can fold it any way through its center and it would match up.

10. Bilateral Symmetry
A bilateral symmetry has only two sides, which are mirror images. A butterfly is an example of it.

11. Human Symmetry
The “Proportions of Man” by Leonardo da Vinci shows the symmetry of the human form.

12. Symmetry form with water reflection
How many lines of symmetry there are in this photograph?
One vertical.
One along the waterline.