an Entity references as follows:
Ivan Ivanovich Schmalhausen (Russian: Ива́н Ива́нович Шмальга́узен; April 23, 1884 – October 7, 1963) was a Ukrainian, Russian and later Soviet zoologist and evolutionary biologist of German descent. He developed the theory of stabilizing selection, and took part in the development of the modern evolutionary synthesis. He is remembered, among other things, for Schmalhausen's law, which states that a population at its limit of tolerance in one aspect is vulnerable to small differences in any other aspect.