1. State bird (robin) --- In 1931, the Michigan Audubon Society held a contest to choose the state bird. About 200,000 votes poured in, most of them for the robin. The people had spoken, so the legislature passed a resolution making the robin---which the legislature called "the best known and best loved of all the birds in the State of Michigan"---the state bird.
2. State flower (apple blossom) --- The apple blossom became Michigan's state flower in 1897, in large part because apples had become one of the state's most significant crops. Because several different types of apples exist, the legislature chose a specific blossom to commemorate: pyrus coronaria, that of the crabapple, which is native to Michigan.
3. State fish (brook trout) --- At first, Michigan's state fish was simply the trout, chosen by the state legislature in 1965. More than twenty years later, the legislature got more specific, and named the brook trout (salvelinus fontinalis) the state fish because it is native to Michigan and abounds throughout the state.
4. State wildflower (dwarf lake iris) --- Yes, Michigan has both a "state flower" and a "state wildflower." In 1996, the Wildflower Association of Michigan ran a poll whose voters decided that the white trillium should be the state wildflower. However, the white trillium grows throughout the entire eastern United States, while the dwarf lake iris---the second-place finisher---grows only in the Great Lakes region. For this reason, along with a desire to promote the iris, whose shoreline habitats were threatened by developers, the state legislature, in 1998, named the dwarf lake iris Michigan's state wildflower. The move was supported by a number of environmental and horticultural groups---except the Wildflower Association of Michigan, which called the legislature's decision "an outrageous power play by select environmental interests over the interests of the people of Michigan."
5. State gem (Isle Royale greenstone) --- Also known as chlorastrolite, the Isle Royale greenstone is bluish-gray in color and has an array of star-like crystals that vaguely resemble the pattern found in a Petoskey stone (though, unlike the Petoskey stone, the Isle Royale greenstone is not a fossil; instead, it's a form of the mineral pumpellyite). Chlorastrolite is found mainly in the Upper Peninsula, and became Michigan's state gem in 1972.
6. State soil (Kalkaska sand) --- The state legislature named Kalkaska sand the official state soil in 1990. (Sidenote: I've never really thought about the fact that different types of soil exist, and that those types are so unique that a state could designate one of them as its symbol, but there you go.) Kalkaska sand, despite being named after a county in the northern Lower Peninsula, exists both above and below the bridge. It was formed in deposits that glaciers left behind during the Ice Age, and contains a mixture of humus (i.e., organic matter that has broken down as far as it can) and light, dark, and yellow sands.