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In the previous paper (Cook and Hartl, 1974) we considered the distribution of gene frequencies in a population evolving in a fluctuating environment when the environmental changes were uncorrelated. In the present article we extend the theory to include autocorrelations in the environment. WVe consider three models. The first (denoted model III in the previous paper) assumes a population reproducing in discrete, nonoverlapping generations accompanied by changes in fitness that occur at regular intervals. The second (called model IVA) assumes a population reproducing continuously in overlapping generations when the random variable on which fitness depends changes at arbitrarily chosen times. And the third (model IVB) assumes a population with overlapping generations in which the environment changes continuously. As before, the transition from model IVA to model IVB is obtained by a limiting procedure. Of the three models, model IVA is the most powerful because it includes the others as special cases and because it is sufficiently general to permit consideration of environments in which the rates of environmental change are themselves changing. One interesting case of model IVA is model IVB. This has recently been analyzed in detail by Gillespie (1972), and here we confirm his results using a markedly different approach.

Monitoring evidence indicates that the Holocene embraced a sequence of rather discrete climatic episodes. The transitions between these environmental episodes apparently were abrupt and globally synchronous. This paper reports on statistical analyses of radiocarbon dates associated with environmental change and cultural change.Over 800 14C dates associated with pollen maxima and minima, sea level maxima and minima, and top and bottom surfaces of peat beds were simultaneously analyzed to identify times of globally synchronous environmental discontinuities.Some 3700 14C dates associated with 155 cultural continua of the world were collectively analyzed to identify worldwide synchroneities in appearance and termination of the cultures.Significant globally synchronous discontinuities were identified in each independent analysis. The dates of environmental and cultural discontinuities are rather similar, particularly during the recent half of the Holocene. The fact that the cultural discontinuities mostly follow rather closely those of the paleobotanical record suggests that there has been a distinct climatic impact on the cultural history of man.

The following paper forms part of an investigation of the relation between the variations of animals and the conditions under which they live. It appears to me necessary that any investigation of this problem should be begun by the examination of cases in which difference in environment is known to exist, and that variations should then be sought for among the forms of life subjected to these conditions. If by this examination any variations can be shown to occur regularly with the change of conditions, or in any way in proportion to their intensity, it is so far evidence that there is a relation of cause and effect between them. By thus first approaching the question from the point of view of the conditions, many difficulties are obviated which occur in any attempt which begins by ascertaining the variations in the animal, in the hope of afterwards finding an environmental change to which they may be traced. Such attempts to trace back variations to some environmental cause have often been made, and have, in general, been unsuccessful. In the case of species which have varied in isolated situations not apparently differing from each other, the failure to find points of environmental difference has been held to be evidence that the variations in question did not arise from such causes at all. This appears likely, and is probably true of the variations in question; but it must be borne in mind that the fact that no palpable difference can be found between the conditions in the several localities is no proof that they do not exist. While these differences in condition are usually evasive and hard to detect, it is best to begin to investigate their relation to variations in animals by selecting cases in which the change in conditions is unequivocal, and proceed from this starting point to seek for correlated variation in the forms of life subjected to them.

This paper examines the relationship between environmental change, changes in competitive dynamics, and top management staffing in the electric utilities industry during the period surrounding the passage of the Energy Policy Act of 1992 (EPAct 92). The findings suggest that following the passage of the EPAct 92, competition in the electric utilities industry intensified, placing greater emphasis on achieving internal, firm-level efficiencies. This external environmental change and the corresponding shift in the competitive context resulted in an adjustment in the composition of the top management coalition in these firms. The dominant coalition following the EPAct 92 consisted of older managers with longer company and industry tenure who had efficiency-oriented backgrounds in operations, engineering, and accounting/finance.

Evolution is a process which yields population systems whose corporate genotype can adjust to and prevail over a defined range of environmental vicissitudes. Populations of most species differ in their ability to exploit current environments and adjust to environmental change and correlatively vary in their probability of survival and reproduction. Those which maximize this probability may be regarded as the most adapted. Populations which contribute the most offspring to the species' gene pool of the following generation relative to other populations may be regarded as the most fit. The distinction between fitness and adaptedness recently has been expounded by Dobzhansky (1968). The definition of populational fitness presented here is based upon a permutation of Dobzhansky's view of Darwinian fitness which he characterizes as "the average contribution which the carriers of genotype, or of a class of genotypes, make to the gene pool of the following generation relative to the contributions of other genotypes." Darwinian fitness is a relative term whereas adaptedness is an absolute term. This paper will deal with dimorphism and adaptedness in the perennial herb Phlox pilosa L. We will consider the adaptedness of pink and white corolla phases within natural populations of P. pilosa and compare the adaptiveness of populations which differ in pink-white balance. Adaptedness will be considered in terms of the ability to exploit a vital environmental resource, namely pollinators. The phase and population which

The question I would like to raise in this brief article is whether there are fundamental physical and chemical limitations on the evolution of organisms able to grow under extreme environmental conditions such as we find in polluted situations. The specific environmental factors I would like to consider are high temperature and low pH, and high temperature and low pH taken together. Temperature and hydrogen ion concentration are probably the most basic environmental factors which organisms must cope with, and both natural and polluted environments exist in which these factors exist in the extreme. The attitude and approach here is quite different than that of the physiologist or biochemist, who looks at how a given organism responds to environmental change. We are interested in how living organisms, taken as totality, respond. This means we must look at stable natural environments which have been available for colonization for millions of years, so that we know there has been time for evolution to reach an equilibrium. We thus study natural thermal and acidic springs, since these provide relatively constant environments of types which have probably been available for colonization as long as life has been present on earth. Much of our own work has been reviewed recently (Brock, 1967, 1969, 1970) so that in the present paper I will give only an outline of past studies and concentrate on recent studies which have not yet been published. To simplify the discussion, I will consider high temperature and low pH separately, and then consider the two factors together.