<title> SUMMARY </title>The eighteenth century images of nature do not all refer to the traditional « scale » model but they rather belong to three distinguished types.The concept of the « scale » was reformulated by some very important philosophers between the seventeenth and the eighteenth century (Locke, Leibniz) and spread by the most eminent naturalists (Tyson, Vallisnieri, Bonnet). It is based on the continuity and fullness of nature and consists in lining up bodies, from the simplest to the most complex, according to an order that is also hierarchical. The popularity of the scale starts decreasing in the first half of the eighteenth century; around 1770 the scale loses all its morphological characteristics and ideological functions and it disappears within a few years.The « map », as the first alternative to the scale, was conceived and put forth by Donati and Linnaeus around 1750. From the empirical point of view it represents the discovery that nature is a much more complex field than was traditionally assumed and, in particular, it shows that the multiple and differentiated affinities existing between living bodies make it necessary to group them " in bunches ". From the theoretical point of view, the map that was popular in the second half of the eighteenth century is the two-dimensional image of any possible type of element, according to the principle that « all what can be, is » (Buffon).The « tree » is different from both the previous images; its history is more complex also because, unlike the scale and the map, the principles it is based upon and the concepts it suggests are different and sometimes in contrast with the previous ones. It was conceived by Pallas (1766) to represent the discontinuity of nature and the separation of the biological world. It became the « genealogical tree » only with great difficulty in 1801, that is the three-dimensional image of evolution: it was Lamarck who, after rejecting the « scale » and the « map », definitively decreed its success in the nineteenth century.