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, one translation of the French besoin, rather than want.
                                                                        The latter implies a teleological, the former an immediate motivation.

(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.