Aleksandr Onufriyevich KovalevskyBorn 19 Nov 1840; died 22 Nov 1901 at age 61. Russian founder of comparative embryology and experimental histology, who first established that there was a common pattern in the embryological development of all multicellular animals. He studied the lancelet, a fish-shaped sea animal; about 2-in. (5-cm) long; then wrote Development of Amphioxus lanceolatus (1865). Then, in 1866, he demonstrated the similarity between Amphioxus and the larval stages of tunicates and established the chordate status of the tunicates. In 1867, Kovalevsky extended the germ layer concept of Christian Heinrich Pander and Karl Ernst von Baer to include the invertebrates, establishing an important embryologic unity in the animal kingdom. This was important evidence of the evolution of living organisms.a.k.a. Alexander Onufrievich Kovalevski. 19 Nov 1849 and 22 Nov 1901 (new style) are 7 Nov 1840 and 9 Nov 1901 (old style). Image: tunicate tadpole larva (L) and lancelet, Amphioxus (R). |
