Russian embryologist and invertebrate zoologist Alexander Onufrevitch Kovalvsky (1840–1901) was one of the founders of cellular and evolutionary embryology. His acclaimed scientific work focused on embryological and invertebrate anatomy of amphioxus, ascidians and other invertebrates. The innovation of this work was to trace the history of adult tissues cell-by-cell from the original egg-cell. Based on these studies, Kovalevsky proposed an evolutionary theory of germ layers and argued that the process of gastrulation is homologous among all animals. Along with his friend and colleague Ilja Iljich Metschnikoff, Kovalevsky published detailed descriptions of most major invertebrate groups. His combination of detailed embryological observations and evolutionary considerations make Kovalevsky one of the founders of an approach now called evolutionary developmental biology.

Key Concepts:

• Kovalevsky was one of the founders of cellular and evolutionary embryology.
  
• Kovalevsky was an embryologist and invertebrate zoologist.