The hypothesis of escalation states that enemies--competitors, predators, and dangerous
prey--are the most important agents of natural selection among individual organisms, and …

▪ Abstract Phylogenetic studies and new fossil evidence have yielded fundamental insights
into the pattern and timing of dinosaur evolution and the emergence of functionally modern …

Biologists often compare average phenotypes of groups of species defined cladistically or
on behavioral, ecological, or physiological criteria (eg, carnivores vs. herbivores, social vs …

The notion that complexity increases in evolution is widely accepted, but the best‐known
evidence is highly impressionistic. Here I propose a scheme for understanding complexity …

Large‐scale evolutionary trends may result from driving forces or from passive diffusion in
bounded spaces. Such trends are persistent directional changes in higher taxa spanning …

During the mid-Palaeozoic, vascular land plants (ie, tracheophytes) underwent a great
radiation that triggered the development of the land biosphere–the so-called Silurian …

The number of cell types required for the construction of a metazoan body plan can serve as
an index of morphological (or anatomical) complexity; living metazoans range from four …

The late Palaeozoic was marked by significant changes in atmospheric chemistry and biotic
composition. Geochemical models suggest a marked increase and then decline of …

A look at the origins of cognitive abilities in primate species. Since Darwin's time,
comparative psychologists have searched for a good way to compare cognition in humans …

Geometric morphometrics (GM) and finite element analysis (FEA) are increasingly common
techniques for the study of form and function. We show how principles of quantitative …