His father, Walter Van Dyke, came from New York and traveled cross-country to California during the gold rush in 1849.
The couple married in 1854 and Walter went on to a successful career as lawyer, judge, and State Supreme Court justice.
In 1890 Van Dyke made his first collecting trip to Yosemite Valley which he reached via pack train.
Van Dyke continued his medical training with postgraduate work in New York City and at Johns Hopkins.
Back in San Francisco he developed a successful private practice and was recognized as a specialist in eye surgery.
He accepted a position at the University of California, Berkeley as Assistant in Entomology, the beginning of a long and successful career as a teacher, collector, and researcher.