he is best known for which works?
"Hydrogéologie" and "Memoirs of Physics and Natural History", to name a few.
Jean-Baptiste Lamarck
While he was working on "Hydrogéologie" (1802), Lamarck had the idea to apply the principle of erosion to biology. This led him to the basic principle of evolution, which saw the fluids in organs inheriting more complex forms and functions, thus passing on these traits to the organism's descendants. This was a reversal from Lamarck's previous view, published in his "Memoirs of Physics and Natural History" (1797), in which he briefly refers to the immutability of species.

who was the first scientist to state that species change over time Lamarck. who was this person? He was a soldier, biologist, and academic.
wiki:1227919
Jean-Baptiste Lamarck [SEP] Lamarckian evolution
He cited examples of blindness in moles, the presence of teeth in mammals and the absence of teeth in birds as evidence of this principle. The second principle was that life was structured in an orderly manner and that many different parts of all bodies make possible the organic movements of animals. Although he was not the first thinker to advocate organic evolution, he was the first to develop a truly coherent evolutionary theory. He outlined his theories regarding evolution first in his "Floreal" lecture of 1800, and then in three later published works: