Lamarck expressed
four laws of evolution in the first volume of his Invertebrate
Zoology.
(1) Life tends to increase the volume & dimensions of
organisms, within limits.
(2) Production of new organs arises from persistent need
[translating the French word besoin,
as need rather than want]. "Need"
implies an immediate motivation, "Want" implies a teleological
end-point
(3) Development of organs are proportional to use & disuse.
(4) Acquired or modified
characteristics are preserved as hereditary
elements that are transmitted to the next
generation. Lamarck does not propose a mechanism.