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Niche parameters of breadth and overlap were calculated on a collection of frog larvae made in 1969 in a seasonal tropical location in Thailand to determine what adaptive strategy characterizes seasonal tropical anurans. Calculation of values of niche breadth and overlap show that space is much more important than food in niche partitioning.

Evolutionary theory has not yet determined the necessary and sufficient environmental factors that can be used to explain the observed diversity of life history patterns in plants and animals. Although recent theoretical treatments of the evolution of life history rely heavily on the concepts of r- and K-selection, we find this framework inadequate to explain life histories of many well-known organisms. Instead, using well-studied examples from the literature, we attempt to identify causal mechanisms in the evolution of their life histories. The density of the population in relation to resources, the trophic and successional position of the population, and predictability of mortality patterns all appear to be important determinants of adaptive strategies. Therefore, consideration of many environmental dimensions seems essential to provide complete understanding of the evolution of life histories.

The functional basis for the relationship between morphological variation and differential niche utilization within and between two species of Basilisk lizards was studied. Variation in body size and allometric changes in the size of functional elements of the hindlimb are correlated with interspecific and intraspecific differences in habitat distribution as well as the behavioral preference and functional ability for use of the adaptive strategy of running on water. Elongated pes, orientation of the toe, and lateral toe fringes provide the drag forces necessary for support and propulsion on water. The functional size of adaptive features within and between species was compared by standardizing measurements of the functional elements as a ratio to body size. Differences in the magnitude of the functional ratios are related directly to the value of the adaptive features to provide for support and propulsion. Least-squares regres- sions of the relationship of the functional ratio to body size within and between species show allometric changes in the functional size of adaptive features that correlate highly with observed habitat preferences as well as the behavioral preference and ability for running on water.

Interpreters of developmental change among tribal societies frequently portray the agents of Western institutions as imposing innovations upon a passive, recipient culture. This study of programs of developmental change among the Papago Indians places emphasis upon the systematic nature of the Indian response which is presented as an adaptive strategy well suited to the rigors of the Sonoran Desert. The Indians are described as employing a centrifugal strategy of reliance upon resources imported from friendly communities external to the Papago homeland. Because of minimal reliance upon other Papago villages or upon the tribal administration developed under the Indian Reorganization Act, this strategy may be designated as restricted interdependence. Efforts at developmental change initiated by the government among the Papago tribe have concentrated upon a centripetal strategy emphasizing reliance upon resources of the Papago Indian Reservation. A feature of this strategy has been the effort to maximize, rather than restrict, interdependence among the units of Papago society. With data from the Papago population register, the possibility that modern communities may have accepted the centripetal strategy of developmental change while conservative villages pursue the traditional centrifugal strategy of restricted interdependence is examined and rejected.

Although the occurrence of mimicry is increasingly well documented and the objections to its evolution have largely been answered (see Sheppard 1959; Wickler 1968; Rettennieyer 1970), the adaptive strategies underlying various types of mimicry are not clearly understood. The ecological concepts of environmental grain or patchiness and of fitness sets as combined by Levins (1962, 1968) permit a consideration of optimal adaptive strategies. Here, we apply this system of analysis to mimicry, and particularly to diverse mimetic strategies exhibited by butterflies (Lepidoptera: Papilionidea). Although Levins (1968) stresses the power of this style of analysis in understanding adaptive polymorphism, his emphasis is on theory. Cody (1966) and McNaughton (1970) apply fitness sets to biological problems, but none of their specific examples combines a consideration of the effects of differences in grain with a consideration of the effects of differences in the factors which change the general shape of the fitness set. We have generally adopted Levins (1968) notation to facilitate comparisons. Examination of optimal adaptive strategies in mimicry using the fitness set approach requires a specification of the shape of the fitness set and the forml of the adaptive function; both are determined by the biological features of the particular case. We have restricted our treatment to mimicry among butterflies, but suggest that our arguments can be applied, with appropriate adjustments for biological realism, to other cases of mimicry. Levins's (1968) parameters can be specified as follows: yi is the mimetic phenotype, Y2 is the "ancestral" nonmimetic phenotype, S1 is a predator encounter state of the environment where yi is the most fit phenotype, S2 is a mating encounter state of the environment where Y2 is the most fit phenotype (alternatively, the environmental axis can be the ratio of predators to potential mates), WV1 is fitness relative to predator avoidance through mimetic resemblance to a relatively unpalatable model, and W2 is fitness relative to visual attractiveness as a potential mate (fig. 1), p is the proportion

Birds and insects are virtually unique among extant forms, sharing only with bats the ability to fly. Having this characteristic in common, it is not surprising that these groups have developed intricate and fundamental ecological interrelationships. Perhaps best known, and to be discussed here, is the preying of birds upon insects. As a group, insectivorous birds display a wide variety of feeding specializations, from hunting upon the wing (swifts, swallows) to excavating deeply in wood (woodpeckers). Roughly 60% of the approximately 8600 species recognized by Mayr & Amadon (50) are partly or largely insectivorous (percentage estimated from 90). Most are relatively small, and some attain high densities (data from breeding-bird and winter bird censuses in Audubon Field Notes). In spite of their small size, their total biomass may make up a high percentage of the avian contribution. Since this diversity and abundance occurs in spite of the severe restrictions imposed by food chain energetics (42, 84), it points out even more clearly the importance of the bird-insect relationship. At least within the macroscopic realm insect diversity on a world-wide scale is unprecedented (49), and in well-studied terrestrial communities the numbers of insect species may reach equally impressive figures (cf. 11). Despite their small size their overall energetic contribution may be substantial (reviewed in 13). Relative to other major taxonomic groups the number of life forms of insects is also impressive (83), and where metamorphosis occurs, it compounds effective diversity. Given their abundance of general life forms and productivity, insects not surprisingly support many predatory species. Flying predators should enjoy a distinct advantage in capturing flying insects and ones in otherwise practically inaccessible locations (tips of vegetation, etc.). This may well represent a partial basis for the high abundance and diversity of birds. In this paper I consider insectivorous birds as "adaptive strategies," that is, as adaptations or sets of adaptations to the spatial and temporal patterning of the environment. Adaptive strategies cut across community barriers and are in theory distinct from special adaptations to particular environmental regimes. For example, will a population become polymorphic or re

The author and his colleagues have pursued a complex path along which they have glimpsed some vistas where investigations might lead to a sharper definition of an adaptive strategy. They have learned that this strategy will involve full participation by government, industry, science, and the public. It was seen that, as the Daddario Subcommittee noted, ''Pollution abatement is affected by so many factors that no one existing institution can have control over all of them.'' The author agrees with the view of this Subcommittee (Daddario, l966) that ''A consortium of public and private interests will be necessary to accomplish what - in very real terms - may be a marked change in the American way of life.''

The theory of plate tectonics implies greatly different continental geographies in the past which can be reconstructed from a variety of geophysical, structural, petrologic, and stratigraphic evidence. Platetectonic processes affect relative sizes, the relative emergence, and the latitudinal and longitudinal patterns of continents. These factors affect the patterns of trophic-resource regimes in shallow marine water and also determine the patterns of provinciality of the shallow-water biota, and these patterns are probably chiefly responsible for the regulation of species diversity in shallow waters. The diversity patterns are partially the products of the adaptive strategies followed by populations in different resource regimes; high diversities correlate with stable regimes and low diversities with fluctuating regimes. The proportions of feeding types vary among types of regime also, resulting in qualitative differences in the faunas. Precam-brian and Cambrian radiations from which the higher invertebra...

Farmer, J. D., Valentine, J. W. and Cowen, R. (Dept. Geol., U. Calif., Davis, 95616). 1973. Adaptive strategies leading to the ectoproct ground-plan. Syst. Zool. 22:233-239. Ectoprocts may have descended from a vermiform, burrow-dwelling lophophorate ancestor that would probably be classed with the Phoronida if it were living. Stripped of their adaptations for small size, coloniality, and skeletonization, ectoprocts closely resemble phoronids. We propose that ectoprocts probably arose from a lineage that became epifaunal, reproducing asexually to form tangled aggregations on hard substrates. Under these circumstances the disadvantages of aggregation, chiefly related to crowding, were mitigated through the development of small body size and by adoption of colonial habit. Coloniality was favored because it regulated intraspecific competition by controlling dispersion patterns and the spacing of individuals. It permitted coordinatedmanipulation of the environment in feeding and waste disposal, enhanced protection, and provided the opportunity for functional differentiation among individuals, thus promoting efficiency. Miniaturization led to the loss of distinct circulatory and excretory systems, while coloniality and eventual skeletonization led to a vast morphological and therefore ecological potential for the group. These factors appear to underlie the important place gained by ectoprocts in many benthic communities from the early Paleozoic until the present time. [Ectoprocts; Phoronida; adaptive strategies.]

This paper describes a computer-baserd monitoring task which is adaptive, or self-adjusting, with the size of the signal stimulus (compared to a fixed non-signal stimulus) being mediated by the detection score of the subject, so as to maintain a constant detection rate. Data are presented which indicate that in order to maintain a fixed detection criterion over a 48-min vigil, the adaptive variable (separation distance of a pair of dots presented simultaneously) behaved in a manner consistent with the usual measures of vigilance decrement. Several adaptive strategies are discussed

— In reply to Lennart Sjoberg's conclusion that the reliabilities and validities of the serial Color-Word Test are at best moderate the present authors claim that, given reliable and adequate criteria, the validities are high. Hence, the true reliabilities can hardly be low. Supporting data are presented. However, the test should not be used merely to identify psychiatric syndrome groups, but rather to broaden our knowledge about them by unveiling their adaptive strategies.

Twenty families each of Avena fatua and A. barbata drawn from a natural population were used for measuring the response to within-family selection for the two extremes in heading date and seed size. The estimates of the relative amounts of between- and within-family variation were interpreted in relation to the realized responses to show that A. fatua has greater genetic variability than A. barbata which, on the other hand, has more phenotypic plasticity. These results support our model on the alternative adaptive strategies in the two species discussed earlier.

Four groups of subjects performed a 48-min, computer-controlled, visual watch-keeping task. Two groups were run under fixed, non-adaptive conditions, one with immediate knowledge of results (KR) and the other without (NKR). The KR group showed the usual superiority in detection rate over the NKR group, and made fewer commissive errors (false alarms). Two other groups, also KR and NKR, ran under adaptive conditions, wherein the size of the signals they watched for was adjusted during the vigil according to past performance, so as to maintain a preset detection rate. The resulting curves for the adaptive variable closely resembled the traditional performance measure, detection rate. Various adaptive strategies are discussed.

The distribution of geinetic variability in deep-sea organisms is virtually unknown, although estimates of genetic variability in the deep-sea fauna are directly relevant to some hypotheses concerning adaptive strategies in stable and unstable environments. One hypothesis, advanced to account for the great species diversity observed in the deep-sea, argues that deep-sea populations are highly specialized and possess little genetic variability (Grassle, 1972). Another hypothesis, also predicting that deep-sea populations should have little genetic variability, has been advanced by Bretsky and Lorenz (1969, 1970) to account for the waves of extinctions registered in the paleontological record. This hypothesis proposes that organisms living in stable environments should be genetically depauperate. Since the deep-sea provides one of the most stable environments in the world, both hypotheses can be tested by examining the amount of genetic variation in deep-sea organisms. In the course of a broad survey of genetic variability in diverse marine environments we have studied the genetic variability of four species of deep-sea asteroids from the San Diego Trough at a depth of 1,244 meters. Allelic variation at 24 individual loci coding for enzymes and other soluble proteins has been studied using the techniques of starch gel electrophoresis.

The research under this grant centered upon two distinct but complementary approaches to the problem of developing implementable non-diverging nonlinear filtering algorithms: decentralized linear filtering approach, and adaptive extended Kalman filtering approach.

Reviews and develops a perspective of what is known about the structure, function, and adaptive strategy of arctic tundra ecosystems, with emphasis on plants, the primary biological producers of an ecosystem. The short-term change in plant arrays following disturbance of the natural assemblage, due to ecological succession, is poorly understood in the tundra. Distribution and migrations of tundra flora give insight into Pleistocene events and evolutionary strategies, one clue to which is frequently of polyploidy. Implicit in understanding tundra dynamics or vegetation associations is study of topographic microrelief, soils and thaw depths, as well as description of the flora. Progress is noted in knowledge of the structure and function of vegetation in arctic ecosystems: the morphological adaptation, carbohydrate cycle, chlorophyll content, physiologic processes in adaption to severe environments such as photosynthesis, respiration, light saturation, photoperiodic requirements and temperature tolerance.

The adaptive strategies of populations are very important elements in the ecological structure of the biosphere. By adaptive strategy is meant a suite of population parameters that is adaptive to the temporal and spatial structure and variability of an environmental regime (see Levins, 1968). In any given range of environments, communities will tend to be composed of species with the particular set of strategies appropriate to the regime. Thus the structure and function of community and of provincial ecosystems reflect to a considerable extent the properties of the environment, varying in such factors as species diversity, pattern of trophic linkages, and proportion of consumers vs. recuperators. The extent to which Mendelian populations follow genetic strategies that contribute importantly to their overall adaptive strategies is still an open question. Adaptive strategies are simply the products of the evolution of a variety of parameters along adaptive pathways that lead to harmonious, advantageous assemblages of population characteristics in a given range of environmental regimes. It seems reasonable that the genetic system itself, which influences the pattern of reproduction, of recombination, and of functional variation in important ways, should reflect population features so that characteristic genetic systems might be favored in certain environmental regimes. Theoretical suggestions to this effect have been made by Carson (1960), Levins (1968), Grassle (1967), Bretsky and Lorenz (1969, 1970) and others. In the fossil record, which is bestpreserved in shallow marine sediments, it is possible to infer changing sequences of adaptive strategies in communities, in provinces, and at times in the entire marine biosphere, presumably in response to important changes in the ancient shallow marine environments (Valentine and Moores, 1970, 1972; Valentine, in press). At times these changes are associated with major waves of extinction, which have swept away high proportions of the marine biota episodically (Newell, 1952, 1956, 1967; Harland et al., 1967; Valentine, 1969). Hypotheses to account for these extinctions are legion, ranging from reliance on occasional extraterrestrial catastrophes to the regular operation of ecological diversity regulators such as are at work today. One current hypothesis is that the extinctions result from the failure of genetic strategies to meet population requirements in changing environments. This hypothesis has far-reaching implications and has stimulated the research on which this report is based.

This article examines the effect of cultural background on the choice of adaptive strategies which various workers employ for dealing with life. A worker's preference among alternative strategies has relevance for many aspects of his work motivation, attitudes and behaviour on the job. The relevance of alternative strategy types for management is discussed and illustrated, and a brief measure of preferred adaptive strategy is provided which can be administered to prospective employees.

ENZYME polymorphisms are known to be widespread in natural populations1–3. No adequate theory has been advanced to account for their frequent occurrence; some workers support the proposition that they are selectively “neutral”4–6, while others present evidence that they are maintained in natural populations through natural selection rather than by non-selective processes1,7–9.

A sequential decision model is discussed to design adaptive receptor for selecting feature subsets in recognition systems. Selection strategies are proposed to choose subsets of features based on the classification results fed back from the classifier. These strategies are adaptive in the sense that the selection is constantly guided by the feedback results in such a way as to maximize the long-run proportion of correct recognition. A character recognition experiment was carried out on a computer-simulated basis to demonstrate the feasibility of this model.

Recent studies of Paleozoic benthic marine invertebrate communities and ecological investigations of modern marine and terrestrial environments have provided information on patterns of faunal density and diversity, patterns which are commonly inferred to be controlled primarily by the physical milieu. Furthermore, there is some evidence indicating that genetic (chromosomal) variability in some invertebrates is correlated with the stability of the physical environment. Previously, these three areas of investigation had not been brought together in consideration of the evolutionary implications of long-term (tens or hundreds of millions of years) environmental stability. Three simple relationships are herein formulated from Recent and fossil data: (l) Environmental stability is positively correlated with diversity; (2) Environmental stability is negatively correlated with long-term biotic (taxonomic) stability; and (3) Therefore diversity is negatively correlated with biotic stability. To explain these observed correlations, we propose an evolutionary model based on genetic-adaptive strategies. We contend that the genetic-adaptive strategy employed by a species population depends in large part on the regularity, direction, and rate of change in environmental stability. A prolonged period of stability could significantly reduce a species' potential for survival in a more rigorous environment, and hence might be expected to precede a time of widespread or mass extinction. A homozygotic genome would be selected for (homoselection) by species subjected to long-term environmental stability, and it is this selection that could ultimately prove disastrous for survival in a later, only slightly less stable regime. Recognizing the teleological pitfalls that appear in any evolutionary model hinting at predictability, we nevertheless believe that attempts at the development of hypotheses based on adaptive patterns or strategies have a very definite heuristic value, if only in preventing the facile recourse to exotic environmental events as an explanation for major evolutionary events in the history of life. The proposed hypothesis of genetic-adaptive strategies should be viewed as a first approximation, perhaps, at best, leading to empirical research, which for now is introduced in an attempt to encourage investigation of environmental events leading up to periods of mass extinction.

In this paper, we describe the learning of psychotherapeutic skills from our observations of the training of first-year psychiatric residents in one specific hospital. This description reflects our conception of the requisite set of skills which any fully formed, presumably competent psychotherapist is expected to master in order to be accredited as a "finished product," i.e., a real professional. We identify some sources of strain involved in the first-year residents' attempts to master these particular skills, and we suggest that much of the tension experienced can be ascribed to the discrepancies between the resident's pre-training orientation towards "normal everyday" social interaction and the new demands posed by psychotherapeutic interaction. We also specify some of the adaptive strategies contemplated by residents as they come to question the efficacy of this skill system. In general, our attempt is to clarify the nature of psychotherapeutic skills and to discuss the way they serve as a pivotal point of reference for organizing the socialization experiences of first-year psychiatric residents.

The adaptive strategy of running on water by the iguanid genus Basiliscus is analyzed and discussed in view of the functional interrelationship between morphology, behavior and the physical nature of the habitat. High-speed cinematographic analysis of the locomotor behavior on water and on a solid substrate shows the aquatic gait to be bipedal and similar to the terrestrial bipedal gait. When Basiliscus runs on water, vertebral flexion and rotation of the pelvic girdle are, however, especially noticeable. A geometric model is presented which permits description of the functional significance of vertebral flexion, girdle rotation and limb retraction in the stride. Differences in locomotor behavior when running on water and on land are shown to be a function of the mechanical properties of the substrate. Hydrodynamic drag provides the forces necessary for support and propulsion in the water. Drag forces result from the elongate pes, rotated orientation of the toes, the presence of lateral toe fringes and the rapidity with which the lizard moves through the water. The functional significance of the toe fringes as a locomotor adaptation is discussed. Toe fringes are shown not to be necessary to permit the lizard to run on water as had been suspected by previous authors. They do, however, increase the efficiency of running on water. Aquatic bipedalism is adaptive as it permits the lizard to avoid both terrestrial and aquatic predators. Furthermore, both interand intraspecific differences in habitat preference and differential niche utilization are shown to correlate with the functional ability to run on the water. INTRODUCTION Exploitation of a specific habitat or parameter of that habitat in a particular fashion -often referred to as "adaptive strategy"-implies a functional interdependence between morphology, behavior and the physical nature of the habitat. The ability to utilize a particular parameter of a habitat is often reflected in habitat preference and niche utilization. It depends largely upon the functional requirements that the habitat demands from the morphological and behavioral adaptive complexes of the animal as well as the effectiveness with which the adaptive complexes of the animal respond to these requirements. Animals employ many odd and unique methods, by human standards, to optimize their opportunities for reproductive success. In many cases it is perhaps the novelty of a particular adaptive strategy which confers its selective advantage, for a new and novel strategy may often provide opportunities for the utilization of unused or unoccupied habitat parameters. The genus Basiliscus (Family Iguanidae) occurs commonly from Tamaulipas and Michoacan in Mexico S to Ecuador and Colombia. The five recognized species have a very distinct preference for an aquatic habitat (Maturana, 1962). They are primarily distributed inland around rivers and streams as well as ponds and small lakes