Education
Saint St. Petersburg State University.
Ichthyologist ornithologist Zoologist
Saint St. Petersburg State University.
He also studied the fish of the Dniester, Dnieper, and Southern Bug rivers, and on the Ukrainian coast of the Black Sea. Kessler was one of the first zoologists to propose that mutual aid, rather than mutual struggle, was the main factor in the evolution of a species. The anarchist Peter Kropotkin later developed this theory in his book Mutual Aid: A Factor of Evolution.
Russian Academy of Sciences.
