Symmetry can be found all around us. You need only look in the mirror to find evidence that the human body is symmetrical. If you draw a line down the middle of your body, you will see that one side is the mirror image of the other side; this is called bilateral symmetry (a.k.a. reflection symmetry or mirror symmetry).
Another common type of symmetry is rotational symmetry. If a figure can be rotated a certain number of degrees about its center and look exactly the same, the figure is said to have rotational symmetry. Plants and animals that exhibit symmetrical features are thought to be healthier than asymmetrical members of their species.
In this video segment from Cyberchase, students will learn how symmetry reveals itself in nature. When Bianca wants to learn why her plants keep dying, she turns to a plant expert at the New York Botanical Garden for insight. The expert shows her some patterns in plants, including bilateral and rotational symmetry, before discovering the pattern that may be killing her plants.