Jean Lamark

Part I of Essay
was a French botanist and invertebrate zoologist who formulated one of the earliest theories of evolution. In 1768 he wrote a book on his botanical observations, which French naturalist Georges Louis Buffon arranged to publish in 1779 as Flore françois (Plants of France). ....

Part II of Essay
.... transmutation, preceded his extensive observational work on invertebrates. With his colleagues, Lamarck accepted the view that animals in nature were arranged on one continuous natural scale. According to Lamarck, once nature formed life, the arrangement of all subsequent forms of life was the result of time and environment interacting with the organization of organic beings. From the simplest forms of life, more complex forms emerged naturally. These ideas were initially presented in Lamarck's major theoretical work, Zoological Philosophy ....