An understanding of the thermal strategies of extant animals is a prerequisite for any useful discussion on the possible thermal strategies of dinosaurs. Of cardinal importance is the identification of the selection pressures that have resulted in the evolution of high body temperatures. Although different selection pressures have probably been operational in different organisms, enhanced muscle power may have been a prime factor.

Many dinosaurs, including the ornithomimids, carnosaurs and hadrosaurs possess cursorial features suggesting high activity levels, which in turn suggest the possession of high body temperatures. Even if it is denied that high body temperatures are a prerequisite for speed, it cannot be denied that muscular activity liberates large quantities of heat, and most dinosaurs, by virtue of their small area to volume ratio, must have maintained constant, and sometimes high, body temperatures. This thermal strategy, described as inertial homeothermy, does not require a high (mammalian/avian) rate of metabolism, and most dinosaurs were probably not endothermic.

The smallest dinosaurs (e.g. Compsognathus) were probably too small to have been able to maintain constant body temperatures in the absence of external insulation. Perhaps they were feathered, like their close relative Archaeopteryx. Presence of feathers in Archaeopteryx is compelling evidence for endothermy.

The largest dinosaurs, the sauropods, had an exceedingly small area to volume ratio, that probably imposed limitations on their rate of heat dissipation. This in turn may have restricted their rate of muscular activity; there are also sound mechanical reasons why they should have been relatively inactive. It is therefore concluded that sauropods probably maintained relatively low body temperatures.

The data on the longevity of genera of articulate brachiopods for the Upper Ordovician-Devonian interval (Boucot 1975) are averaged for the taxa of each order. The generic longevity-frequency distributions form three significantly different clusters. The orthids have the highest mean generic longevity value and display a semi-log survivorship profile that is more convex than the other orders. The spiriferid and strophomenid orders have mean generic longevity values higher than and slopes in the survivorship curves less steep than the pentamerids, rhynchonellids and terebratulids. The appreciable differences in the inferred generic extinction rates for the clusters are attributed to the heterogeneity of the ecologies of the orders. The pentamerids had a proportionately higher number of genera concentrated in narrow-niched reefs wherein higher extinction rates depressed the mean generic longevity of this order relative to the orthids, strophomenids and spiriferids. Enhanced longevity of many offshore (non-reef) genera possibly explains the greater mean generic longevity of the orthids, spiriferids and strophomenids relative to the rhynchonellids and terebratulids which included a proportionately higher number of genera concentrated in nearshore habitats. Alternatively, the depressed mean generic longevity values for the rhynchonellids and terebratulids may reflect systematic oversplitting and temporal bias, i.e., origination and initial diversification of order.

The hyrax, a living primitive subungulate, makes an ideal model in terms of its molar morphology for early lophodont ungulates. Cine fluoroscopic studies of mastication show that the proposed Phase II in jaw movement, experimentally demonstrated in primates, but surmised in ungulates only from molar wear facets, does in fact exist in this animal, but does not appear to be an important component of the masticatory cycle. Comparison of tooth wear in early Tertiary ungulates with contemporaneous primates shows that, whereas primates enlarge the Phase II wear facets on the molars as they move into more herbivorous niches, the same is not true for ungulates, and in fact Phase II may be lost altogether in grazing forms. It is concluded that “grinding” in herbivorous ungulates is a process fundamentally different from that described for herbivorous primates.

The organic matrix components of a fossil ammonoid shell from the Upper Cretaceous, can be separated into sub-fractions which are generally comparable to those found in extant Nautilus, using ion exchange chromatography. This suggests that at least portions of these components are sufficiently well preserved to interact characteristically with the ion exchange resin. Amino acid compositions of these sub-fractions, however, do not resemble Nautilus organic matrix sub-fractions, indicating that considerable diagenetic alteration of this material has taken place.

We present a quantitative method for describing how heterochronic changes in ontogeny relate to phyletic trends. This is a step towards creating a unified view of developmental biology and evolutionary ecology in the study of morphological evolution. Using this representation, we obtain a greatly simplified and logical scheme of classification. We believe that this scheme will be particularly useful in studying the data of paleontology and comparative morphology and in the analysis of processes leading to adaptive radiation. We illustrate this scheme by examples drawn from the literature and our own work.

The mathematical relationship between species survivorship and duration curves is derived using standard demographic arguments. The result, when applied to the late Cenozoic mammals, suggests that there was an inhomogeneity in the mammalian radiation just before the Wurm, or that the mammalian speciation process has not yet attained the stable-age distribution.

The EDTA-soluble fractions extracted from rostra of two late Cretaceous belemnites (Cephalopoda), Gonioteuthis and Belemnitella, were divided into an humic acid and a fulvic acid fraction (the latter was absent in Belemnitella). The extracts are compared with preparations from shells of two recent cephalopods, Nautilus pompilius and Sepia officinalis. Use was made of immunology, amino acid analysis, pyrolysis mass spectrometry and some other techniques.

The fulvic acid fraction of Gonioteuthis, a mixed peptide-like saccharide-like substance, produced confluent immunodiffusion patterns with an EDTA-soluble Nautilus extract against anti-Nautilus rabbit serum. The humic acid of Gonioteuthis did not contain D-alloisoleucine and its amino acid composition was very similar to that of the EDTA-insoluble fraction of Nautilus. This humic acid was enriched in polyphenol, which may be due to chemical reaction of peptides and carbohydrates during diagenesis. It is concluded that both fractions of Gonioteuthis are original belemnite materials that have undergone only minor alterations during diagenesis.

This is an exploratory study of biochemical compounds derived from fossils, with particular emphasis on immunological methods.

Regular discontinuities in the distributions of morphological measurements may conceivably reveal tempos in evolution. Recently L⊘vtrup et al. (1974) attributed apparent stepwise interspecific variation in mammalian and avian body size to an evolutionary cause: according to these workers, the pattern may reflect punctuation in phylogeny caused by speciation. The nature and appropriate use of data, the choice of techniques for detecting patterns, and the implications of the results of such tests are discussed here in the light of this Swedish study. A technique, which may be used to verify patterns in rose diagrams or a range of ostensibly rhythmic phenomena, is described and applied to new data. Clustering is found at intervals other than those predicted by L⊘vtrup et al., but there is no consistent trend in the values of these interval lengths among data sets.

Experienced workers in a field are unlikely to change their assessment of basic philosophical issues. Einstein for example never accepted the indeterminacy required by the Heisenberg uncertainty principle, despite the urgings of Max Born and virtually all others. Similarly even earlier, some older workers had refused to accept the young Einstein's theories. Now if issues in physics are not open and shut, they are even less so in paleontology. Possibly it is useful to probe the underlying basic philosophical background to our discipline. The purpose of the present article is to indicate that the inductive, deterministic approaches which have been used almost exclusively in paleontology have stringent limitations. For some types of problems, deductive stochastic processes are more interesting. If we can make the distinction of ‘few’ versus ‘many,’ then it is quite easy to consider deterministic explanations for the individual cases (the movement of individual molecules) but to reserve stochastic explanations for the ensembles of events (the movement of molecules too numerous to count).

A paradoxical relationship exists between the genetic and morphologic adaptive strategies of benthic marine invertebrates; morphologically variable species from unstable environments have been shown to possess less genetic variability than species with more constant phenotypes from stable habitats. The mode of growth of Ordovician bryozoans provides an insight into this paradox. These bryozoans exhibit morphologic gradients within zooidal subcolonies that change throughout colony development. Entire clusters of zooids begin and cease growth as a function of their spatial position with respect to neighboring clusters. A comparison of the within-colony and among-colony components of developmental and morphologic variability was made from populations inhabiting Ordovician environments of differing stability. In four stratigraphically persistent species, the level of developmental variability is homogeneous within species, but varies significantly across taxa. The two species with the highest levels of developmental variability (less canalized development) fit the concept of r-selected opportunistic species and are most abundant in communities of lowest diversity. The other two species have much lower levels of variability (more canalized development), fit the concept of K-selected equilibrium species, and are most abundant in the communities of highest diversity. Within-colony morphologic variability is also higher in the opportunistic rather than the equilibrium species, indicating that the higher morphologic variability observed in unstable environments is the product of within-genotype deregulation, and not the result of higher genetic polymorphism. The equilibrium species in stable environments have lower levels of morphologic deregulation and correspondingly greater variation among genotypes than within genotypes in fossil populations.