Macroevolutionary Events and the Origin of Higher Taxa

Abstract

The role of macromutation as a source of evolutionary novelty is discussed in relation to the repeatedly appearing reticulate pollen grain morphology; the origin of stomata by pedomorphic transformation of gametangial conceptacles in the alga-like precursors of vascular plants; the fixation of environmentally induced anomalous stomatography as a genus-specific character; the origin of specialized seedling morphology in mangroves through changes of developmental rates; the cyclic evolution (retroconvergence) of reproductive and foliar characters; the possibility of pathogenic cecidogenous origin of plant organs; and the diversification burst (anastrophes) on the basis of macropolymorphic post-crisis populations. Macromutation can be involved in both micro- and macroevolutionary processes, yet the origin of higher taxa is not reducible to a single macromutation event. Rather, it is an accumulation of macromutational novelties arising in different lineages, as well as a retrieval of ancestral characters lost in the immediate ancestors, but retained in the genomic memory and their integration in the new adaptive context.