Foraminifera—Earth's Microscopic Recordkeepers

The word "foram" is short for foraminifera, a class of single-celled microorganisms known as protists. They first appeared in the rock record about 540 million years ago. Today, most forams range in size from 0.1 to 1 mm, but in the geologic past, forams have been as big as 20 cm. Forams are important for their roles as timekeepers of geologic age, as indicators of mass extinction and climate changes, and as pollution monitors. This poster describes these roles and illustrates forams' many shapes and sizes.

(This poster is designed to be printed at a maximum of 31.125" x 24".)