After completing his studies in medicine and biology, a restless
Ernst Haeckel set off for Italy in 1859 to study art and marine
biology. The diversity of life fascinated the 26-year-old
Prussian, and in addition to painting landscapes, he spent the
climactic months of his stay glued to his microscope observing
and sketching radiolaria—protozoa encased in delicately ornate
silica skeletons—that he collected off the Italian coast and
sent back to Berlin. He was amazed by the diversity of their
forms, which seemed to come in limitless, but sortable,
varieties, and on returning from Italy set to work cataloging
them. During this time of youthful soul-searching and vocation-
finding, Haeckel stumbled upon a German translation of the
recently published Origin of Species and experienced one of the
most momentous revelations of his career. In the fourth chapter
of Charles Darwin’s treatise was a drawing that illustrated the
evolution of a single hypothetical species into a genus of 8
species across 14,000 generations