Evolution__3rd_Edition

474 PART 4 / Evolution and Diversity
(a)
(b)
(c)
Rhinoceros Beetle Butterfly
Limpet Barnacle Lobster
Lizard Crocodile Bird
Phenetic Phylogenetic
Butterfly
Beetle
Rhinoceros
Lobster
Barnacle
Limpet
Butterfly
Beetle
Rhinoceros
have left behind a rump of quite distantly related groups that resemble one another
phenetically (Figure 16.1c). We discuss these two problematic cases further later on,
but the illustrations in Figure 16.1 are enough to introduce the three main schools of
classification.
16.3 There are phenetic, cladistic, and evolutionary schools
of classification
Lizard
Crocodile
Figure 16.1
The phenetic and phylogenetic principles of classification may (a) agree or (b–c) disagree.
We distinguish phenetic,
phylogenetic, and evolutionary
taxonomy
Bird
Lobster
Barnacle
Limpet
The phenetic and phylogenetic principles are the two fundamental types of biological
classification, but three schools of thought exist about how classification should be
carried out. The chapter will discuss these three schools, and Table 16.1 summarizes
their main features.
The most influential school of phenetic classification is (or was) numerical
taxonomy. It was particularly defended by Sneath & Sokal (1973). The terms phenetics,
numerical phenetics, and numerical taxonomy are used almost interchangeably in
modern biology.
Phylogenetic classification has been defended by the German entomologist Hennig
(1966) and his followers; Hennig called it phylogenetic systematics, but cladism is now
the commoner term. We saw how cladistic techniques are used to infer phylogeny in
Chapter 15.
Lizard
Crocodile
Bird
..