Three centuries of paradigm changes in biological classification: Is the end in sight?

Classification has been a centerpiece of biology ever since Linnaeus, providing a framework on which existing knowledge can be organized and predictions about unknown traits can be made. But the basis of biological classification has gone through a series of upheavals over the last three centuries, from being considered a plan in the mind of the creator, to a neutral assessment of overall similarity, to a reflection of evolutionary niches, and finally to a phylogenetic mapping of the tree of life. This paper will consider this historical process, with emphasis on phylogenetic systematics (cladistics), and also consider where we might be heading in the future. It is necessary first, however, to consider the purposes of classification itself, which have not changed much over time.