The great seal of Michigan also appears on both sides of the state flag. The moose and elk represent Michigan, the bald eagle is a symbol for the United States.

Meaning of Latin Phrases on State Seal:

E Pluribus Unum: From Many, One
(our nation was made from many states).
Tuebor: I Will Defend
(refers to the frontier position of Michigan).
Si Quaeris Peninsulam Amoenam, Circumspice:
If you seek a pleasant peninsula, look about you.
(also Michigan's state motto).

Source:

Coat of Arms: Michigan Department of State
Michigan FAQ: Michigan.gov
Getting to Know Michigan: Michigan.gov

Links:

Coat of Arms: Michigan Department of State
State Seals - 50 States List
National Seal