We will learn all about bilateral symmetry and look at some examples.
The advantages of bilateral symmetry will also be discussed. Then, you can take the quiz to check your knowledge.
In order to fully define bilateral symmetry, we need to first define symmetry. Symmetry has to do with the orientation of an organism based on a plane or around an axis. Considering the different shapes and orientations of various organisms, scientists have come up with three basic types of symmetry.
The first type is radial symmetry.
With this type of symmetry, the body plan is based around an axis. In other words, the body is oriented so that it radiates out from an imaginary line through the center of the organism. These organisms have a top and bottom, but they don’t have a left and right side or a front and back side. A couple examples of radial symmetry are starfish, jellyfish, and sea anemones.
The last type of symmetry is the bilateral symmetry.
Bilateral symmetry is when the body plan can be divided along a plane that splits the animal’s body into right and left sides that are mirror images of each other. Let’s look at this type of symmetry a little more.
Examples of Bilateral Symmetry
So, now you may be trying to think of the different animals that display bilateral symmetry. Well, guess what? You are the first example that we’re going to discuss. Yep, we humans are an example of bilateral symmetry. Go ahead and take a look in the mirror and see for yourself. We could draw a line straight down the middle of your body, right through your nose, and divide you into right and left mirror images.
Even your brain can be divided into equal right and left sides. Okay, you get the picture.
|*Bilateral symmetry means that the body can be divided along a plane that divides the animal into left and right sides. *Humans, dogs, and even sharks can exhibit bilateral symmetry.||*Formation of a head and tail area *Increased sensory abilities *Formation of a more complete nervous system *Ability to move in all directions|
After analyzing this lesson in detail, see if you’re prepared to achieve these objectives:
- Enumerate the three types of symmetry, and give examples of each kind
- Discuss the benefits of bilateral symmetry