Final answer:
Jean-Baptiste Lamarck was a French naturalist who proposed the first theory of macroevolution, based on the inheritance of acquired characteristics. Despite being discredited, his ideas were influential in the development of evolutionary thought.
Step-by-step explanation:
Jean-Baptiste Lamarck was a French naturalist who proposed the first theory of macroevolution. He believed in the idea of the inheritance of acquired characteristics, which suggested that modifications in an individual caused by its environment or the use/disuse of a structure during its lifetime could be passed on to its offspring and bring about change in a species. Despite the discrediting of Lamarck's theory, his ideas significantly influenced the development of evolutionary thought.