Johannes Japetus Smith Steenstrup (1813–1897) was a Danish zoologist, biologist, and professor.
He was a professor of zoology at the University of Copenhagen. He worked on a great many of subjects, including cephalopods, but also in genetics, where he discovered the principle of the alternation of generations in some parasitic worms in 1842.
Steenstrup discovered (1842) the possibility of using the subfossils of the Postglacial as a means of interpreting climate changes and correlated vegetation change, which he called succession in the recent past.[1] Two of Steenstrup's students, Christian Vaupell and Eugen Warming further developed this line of research.
Japetus Steenstrup was a professor to zoologist Johan Erik Vesti Boas, who was also a student of zoologist Carl Gegenbaur, and Hans Christian Gram, inventor of the Gram stain. [2]
Together with Johan Lange, Steenstrup was the publisher of Flora Danica fasc. 44.
In 1857, he was elected a foreign member of the Royal Swedish Academy of Sciences.