His work in systematic zooelogy, unlike that of Linne, and especially of Cuvier, was that of a far higher grade.

Lamarck, besides his rigid, analytical, thorough, and comprehensive work on the invertebrates, whereby he evolved order and system out of the chaotic mass of forms comprised in the Insects and Vermes of Linne, was animated with conceptions and theories to which his forerunners and contemporaries, Geoffroy St.Hilaire excepted, were entire strangers.
His tabular view of the classes of the animal kingdom was to his mind a genealogical tree; his idea of the animal kingdom anticipated and was akin to that of our day.

He compares the animal series to a tree with its numerous branches, rather than to a single chain of being.

This series, as he expressly states, began with the monad and ended with man; it began with the simple and ended with the complex, or, as we should now say, it proceeded from the generalized or undifferentiated to the specialized and differentiated.

He perceived that many forms had been subjected to what he calls degeneration, or, as we say, modification, and that the progress from the simple to the complex was by no means direct.