Chemical analyses of fossil plants and their associated sediments are currently providing the paleobotanist with biochemical information relevant to the reconstruction of taxonomic relationships. The isolation and chemical identification of various plant pigments from fossils, such as flavonoids and carotenoids (compounds that give flowers their characteristic colors), steroids, fatty acids, and a host of plant phenolic acids, provide the opportunity to characterize the specific paleophytochemical profiles of fossil species.

Birds have traditionally been termed the best known group of vertebrates. This cliché, however, relates to the fact that living species are well described, even to the subspecies level. Birds are well known because they are diurnal (therefore easily observed) and because of their aesthetic appeal—birds are beautiful. Because of this appeal, birds have been subject to persistent scrutiny by amateur and professional naturalists alike, and their study has consequently contributed to the development of not only evolutionary thought, but also such diverse fields as ecology, behavior and even comparative physiology. However, while these disciplines have advanced, our understanding of bird phylogeny and evolution has simply not kept pace and the relationships of the higher categories of birds are still very poorly understood.

In the past twenty years, both knowledge of fossil plants and ways of looking at the paleobotanical record have expanded significantly. Studies of Precambrian microfossils have provided insight on early photoautotrophs, while fundamental changes in perceptions of Silurian and Devonian plant remains have clarified our understanding of the colonization of land, as well as the subsequent evolution of complex stems, leaves, and the seed habit. A recurring question concerns the phylogenetic relationships of gymnosperms: is the gymnospermy found in various living and extinct taxa the result of evolutionary convergence or of common descent? Rapidly accumulating data on the reproductive and developmental biology of Paleozoic seed ferns is reopening debate on this issue. The mystery of angiosperm origins remains “abominable”, but the past two decades of research have seen convincing documentation of the initial radiation and rise to taxonomic and ecological dominance of the flowering plants.

While phylogenetic and systematic botany remain at the core of paleobotanical research, increased attention is being devoted to studies of ontogeny and reproductive biology, paleoecology, taphonomy, paleophytochemistry, paleoclimatology, and paleobiogeography. Studies of evolutionary rates and diversity are in their infancy, but initial results permit an optimistic appraisal of the contributions that paleobotanists can make to evolutionary paleontology.

Data on numbers of marine families within 91 metazoan classes known from the Phanerozoic fossil record are analyzed. The distribution of the 2800 fossil families among the classes is very uneven, with most belonging to a small minority of classes. Similarly, the stratigraphic distribution of the classes is very uneven, with most first appearing early in the Paleozoic and with many of the smaller classes becoming extinct before the end of that era. However, despite this unevenness, a Q-mode factor analysis indicates that the structure of these data is rather simple. Only three factors are needed to account for more than 90% of the data. These factors are interpreted as reflecting the three great “evolutionary faunas” of the Phanerozoic marine record: a trilobite-dominated Cambrian fauna, a brachiopod-dominated later Paleozoic fauna, and a mollusc-dominated Mesozoic-Cenozoic, or “modern,” fauna. Lesser factors relate to slow taxonomic turnover within the major faunas through time and to unique aspects of particular taxa and times.

Each of the three major faunas seems to have its own characteristic diversity so that its expansion or contraction appears as being intimately associated with a particular phase in the history of total marine diversity. The Cambrian fauna expands rapidly during the Early Cambrian radiations and maintains dominance during the Middle to Late Cambrian “equilibrium.” The Paleozoic fauna then ascends to dominance during the Ordovician radiations, which increase diversity dramatically; this new fauna then maintains dominance throughout the long interval of apparent equilibrium that lasts until the end of the Paleozoic Era. The modern fauna, which slowly increases in importance during the Paleozoic Era, quickly rises to dominance with the Late Permian extinctions and maintains that status during the general rise in diversity to the apparent maximum in the Neogene. The increase in diversity associated with the expansion of each new fauna appears to coincide with an approximately exponential decline of the previously dominant fauna, suggesting possible displacement of each evolutionary fauna by its successor.

Almost every living and fossil group of gymnosperms has been proposed as a possible ancestor of angiosperms. A common problem with many of these proposals is their reliance on hypothetical intermediate forms. Another common problem is finding correctly-oriented organs homologous to all the important reproductive structures of angiosperms.

These problems are least troublesome for a glossopterid origin of angiosperms. Recently discovered ovule-bearing organs of these plants may represent evolutionary intermediates, or analogous plants, between glossopterids and angiosperms. According to recent reinterpretations of glossopterid ovule-bearing organs, they have structures in an orientation which may be homologous with both the outer ovular integument and the carpel of angiosperms. Considering the reproductive and vegetative features of glossopterids, the hypothesis that they may be part of a stock ancestral to angiosperms should be seriously considered.

Cheilostome bryozoans that grew as rigidly erect arborescent colonies dominate many bryozoan-rich assemblages of Tertiary age, in which they are found most commonly as small dissociated fragments. The regularity with which branching and branch thickening occur in intact colonies of living species provides a basis for quantitative reconstruction of these growth processes in fossils. We propose models to describe branch thickening, develop methods to extend both thickening and branching models to fossils, investigate the thickening and branching properties of four Paleocene and five Oligocene species and compare the properties of these fossils to those of nine living species.

The properties investigated are largely mutually independent and species specific irrespective of geologic age and have similar numerical ranges among different assemblages of coeval species. Species are evenly distributed across the range of possible morphologies between observed extremes, without obvious gaps. Statistically significant trends through time are identified in gradients of branch thickening, which have implications for the resistance of colonies to mechanical stress, and in angles of bifurcation, that are important in the way growing colonies occupy space.

The pedicle differentiates brachiopods from all other phyla. With its associated musculature, it is more variable than any other brachiopod system at or above the generic level and is considered to contribute to the versatility of behavior possessed by some species. Differences in pedicle type are reflected clearly in the beak.

Quantification of Paleozoic, Triassic, Jurassic, and Cretaceous ammonoid shell ornamentation shows that commonality and roughness of ornamentation increased throughout the geologic range of the ammonoids. The two major hypotheses concerning the function of ammonoid shell ornamentation are that 1) ornament served a protective (defensive) function against shell breakage by predators, and 2) it increased hydrodynamic efficiency of the shell during swimming. The heavily ribbed and spined ammonoid shells of the late Mesozoic have ornamentation too coarse to have served any hydrodynamic purpose. The increasing proportion of such shells during the Jurassic and Cretaceous may have been in response to increased numbers of late Mesozoic shell crushing predators and “better armed” ammonoid prey. This trend parallels adaptive trends of other invertebrate groups during the “Mesozoic marine revolution” as defined by Vermeij (1977).

Size variation among several species of large mammals is examined both throughout a wide geographical range today and within the Late Pleistocene-Holocene archaeo-faunal sequence of Israel. A regression of log dental size on environmental temperature produces similar negative slopes for recent Palaearctic foxes, wolves and boars as well as for Nearctic foxes. These species, and others which also exhibit an inverse correlation between size and temperature today, became dwarfed at the end of the Pleistocene in Israel. Abundant fossil gazelle and fox mensural data indicate that this diminution coincided with the temperature elevation 12,000 yr ago. Both the similarity of regression slopes for the recent material and the temporal coincidence of dwarfing among fossil species, representing different ecologies, strongly implicate temperature as the main body-size determining factor. Changes evidenced in the fossil record for boar, wolf and fox approximate a 15°C temperature change (Δt) based on their respective present-day size-temperature regressions. This Δt, if taken as an estimate for the eastern Mediterranean, is considerably higher than generally accepted values.

An additional size reduction of aurochs, wolf and boar at the end of the Pleistocene or several millenia later is associated with their domestication. It may reflect man's preference for a large “head count” over individual large body size.

Using computer simulations and analytic calculations, we have evaluated whether conspicuous expansions and contractions of natural clades may have represented chance fluctuations that occurred while probabilities of speciation and extinction remained equal and constant. Our results differ from those of previous workers, who have not scaled generating parameters empirically at the species level. We have found that the waxing and waning of many real clades have almost certainly resulted from changes in probabilities of speciation and extinction. For some of these changes, likely explanations are evident. The emplacement of adaptive innovations, for example, has at times elevated probability of speciation. We conclude that chance factors have not played a dominant role in producing dramatic changes in standing diversity within speciose higher taxa.

Gould (1980) claims that a “new and general theory of evolution” is emerging. He examines the modern synthesis and asserts that it is being rejected by present day evolutionary biologists. The purpose of this note is to show that Gould's view of the modern synthesis is distorted. Any rejection of the modern synthesis must rest on a more balanced characterization than that presented by Gould.

As The Blob, of Steve McQueen's greatest triumph, so amply demonstrated, the more you encompass the more formless you become. Orzack accuses me of construing the modern synthesis too narrowly in describing a version championed only by Mayr and Fisher—a pair of unlikely bedfellows, I would have thought. Yet his version is so broad that he wins his own argument by internal definition, thus rendering it meaningless. As “the basis of the modern synthesis,” Orzack cites “the great evolutionary idea” — “all evolution can be explained in principle by an examination of the properties of individuals and of populations.” But what else is there, except perhaps Schindewolf's supernovae and Teilhard's ever-watchful Jesus, drawing organic activity towards Omega. If the synthesis only excludes some fringing finalists and unrepentant Lamarckians, then we are all inevitably in it, and we might as well recast the term as a synonym for evolution itself.