Fig. 4

Different patterns resulting from anagenetic versus cladogenetic trends. In a, most of the directional change occurs within species, and branching to form new species (speciation or cladogenesis) does not contribute to the occurrence of the trend. In b, which reflects a pattern of speciation known as “punctuated equilibria,” most morphological change occurs in association with speciation events, and the trend is said to be cladogenetic because change occurs primarily among species, not within them. Based on Gould (1990)