Intro to Zoology – Unit 1 Animal Body Plans

Animal Symmetry Symmetry –Refers to balanced proportions, or correspondence in size and shape of parts on opposite sides of a mid-line. Asymmetrical – Body design that is not divisible into equivalent parts.

Radial symmetry Oriented around the center of its axis. Looks like the hub of a wheel with spokes. Best examples of radial symmetry in zoology are starfish and sea anemones.

Bilateral Symmetry Also referred to as mirror symmetry If a bilateral animal were divided in half, each half would look very much alike

Key terms in locating regions of animal bodies Anterior – Designates the head, or front end Posterior – The opposite or tail end Dorsal – The side usually away from the pull of gravity; the back side Ventral – The side usually toward the pull of gravity; the belly side Appendages – Coming from the main body trunk; used for locomotion and feeding

Key terms in locating regions of animal bodies Medial – midline of the body Lateral – the sides of the body Proximal – parts that are nearer the middle of the body Distal – Parts that are farther from the middle of the body

Skeletal Support Endoskeleton – Provides internal support and structure Exoskeleton – Provides support and structure outside the body’s muscle tissue

What type of symmetry do each of the following exhibit?

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.