Evolution: questions for the modern theory.

The blind spot of the present generation of evolutionists is failure to see the consequences and limits of natural selection. Darwinian natural selection is a costly process of differential elimination of individuals. The widely accepted misdefinition of natural selection as differential reproduction mistakenly hides the Darwinian process and its cost. And current theories of selfish genes, inclusive fitness, and kin selection are incompatible with Darwinian selection. Implicitly, if not explicitly, they postulate genes that favor themselves but reduce the Darwinian fitness of the individuals carrying them. Such genes would not survive; they would eliminate themselves by causing the selective elimination of their carriers. Critical questions that evolutionists should be asked are suggested. My own "unhappy conclusion" is that, because most biologists have forgotten what natural selection is, much current evolutionary and sociobiological theory presented by the most influential evolutionists is mistaken and dangerous. Anthropologists and sociologists are wise to distrust it.

Genes, individuals, and kin selection.

The altruistic-gene theory of kin selection requires conditions so improbable that its reality is doubtful. The gene-quantity theory, including the theory of inclusive fitness, assumes that selection acts on sums of kins' genes, but no effective mechanism is apparent. Insect and human societies may have evolved by individual selection, in two steps: first something made staying together advantageous to individuals, and then altruistic behaviors evolved in net-gain lotteries, also (statistically) advantageous to individuals. Kin selection is not required in these or any other unequivocal cases; the theory should be reexamined and probably abandoned. The probability of kin selection is further reduced by the cost of evolution by selection. Much current evolutionary mathematics and determinist sociobiology, which ignore how the cost of selection limits the precision of adaptations, including adaptive behaviors, may be dangerously unrealistic.

Altruism: its characteristics and evolution.

Altruism is a group phenomenon in which some genes or individuals, which must be presumed to be selfish, benefit others at cost to themselves. The presumption of selfishness and the fact of altruism are reconciled by kin-group selection and by reciprocal altruism. Kin-group selection is clearly visible only in special cases; its role even among social insects may be overestimated; it is probably usually inhibited by competition. However, reciprocal altruism is ubiquitous. All altruism is: (i) potentially reciprocal; (ii) potentially profitable to altruists as well as to recipients; (iii) environmentally determined, usually by position of individuals in group or environmental situations; and (iv) a net-gain lottery. These generalizations are illustrated by four idealized cases; the difficulty of applying them to real cases is illustrated by alarm-calling in groups of birds. Although altruism is a group phenomenon, it evolves by individual selection, by processes equivalent to co-evolutions. Its evolution is: (i) opposed by competition; (ii) costly, complex, and slow, and tending to produce an imprecise flexible altruism rather than a precisely detailed one; and (iii) supplemented by group selection (differential extinction of groups). That altruism in human beings conforms to these generalizations is a good working hypothesis. However, analysis does not "take the altruism out of (human) altruism." Humans do not calculate it, but behave altruistically because they have human altruistic emotions.

The cost of evolution and the imprecision of adaptation.

Comparisons of six hypothetical cases suggest that Haldane overstimated the cost of natural selection by allele substitution. The cost is reduced if recessive alleles are advantageous, if substitutions are large and few, if selection is strong and substitutions are rapid, if substitutions are serial, and if substitutions in small demes are followed by deme-group substitutions. But costs are still so heavy that the adaptations of complex organisms in complex and changing environments are never completed. The rule probably is that most species most of the time are not fully adapted to their environments, but are just a little better than their competitors for the time being.

Group selection, altruism, reinforcement, and throwing in human evolution.

Evolution of altruism by group selection involves sacrifice of some individuals, not to the "group as a whole," but to other individuals in the group. Deme-group selection may establish strictly altruistic genes in a population, but only under limited conditions, and perhaps never among vertebrates, among which apparently altruistic behaviors may always potentially benefit the altruists. Responsive-group selection is a more effective mode of evolution of altruism, conspicuous in man. Evolutionary reinforcement increases the force of selection of advantageous behaviors, including altruistic ones, by making them pleasant or rewarding. It is probably involved also in ecological habitat selection, and may be the source of many human emotions, including esthetic ones. Throwing (of stones and weapons) exemplifies both the possible importance of a difficult-to-measure evolutionary factor and the role of reinforcement; in human evolution throwing may have been decisive in food-getting and fighting, in shifting emphasis from brute force to skill, and in inducing evolution of a brain able to handle three-body geometric problems precisely and thus preadapted for more complex functions.

Competition, competitive repulsion, and coexistence.

This manuscript is concerned with concepts rather than abstruse details or mathematics. Discussed are: competition; extended competition, proposed for competition in the strict sense, extended and modified by all related interactions including predation, parasitism, disease, and even cooperation, all of which can be "weapons of competition"; competitive repulsion, proposed for the sum of forces that determine spacings, including ecologic spacings, of individuals and populations; Darwin (biotic) equilibriums; competitive extinction, Gause's principle, limited and limiting resources, and single-resource competition; de facto coexistence of competing species, exemplified by green plants competing for sunlight; niche competition; the two concepts of competitive exclusion; devision of resources and of their utilizers; cause and effect in real situations; and niches, niche overlap, and coexistence. Stressed is the complexity of the real world, and the confusion that can and does arise from modeling it too simply.

Nonmathematical concepts of selection, evolutionary energy, and levels of evolution.

The place of mathematics in hypotheticodeductive processes and in biological research is discussed. (Natural) Selection is defined and described as differential elimination of performed sets at any level. Sets and acting sets are groups of units (themselves sets of smaller units) at any level that may or do interact. A pseudomathematical equation describes directional change (evolution) in sets at any level. Selection is the ram of evolution; it cannot generate, but can only direct, evolutionary energy. The energy of evolution is derived from molecular or chemical levels, is transmitted upwards through the increasingly complex sets of sets that form living systems, and is turned in directions determined by the sum of selective processes, at different levels, which may either supplement or oppose each other. All evolutionary processes conform to the pseudomathematical equation referred to above, use energy as described above, and have a P/OE (ratio of programming to open-endedness) that cannot be measured, but can be related to other P/OE values. Phylogeny and ontogeny are compared as processes af directional change with set selection. Stages in the evolution of multi-cellular individuals are suggested, and are essentially the same as stages in the evolution of some multi-individual insect societies. Thinking is considered as a part of ontogeny involving an irreversible, nonrepetitive process of set selection in the brain.

Nonmathematical models for evolution of altruism, and for group selection (peck order-territoriality-ant colony-dual-determinant model-tri-determinant model).

Mathematical biologists have failed to produce a satisfactory general model for evolution of altruism, i.e., of behaviors by which "altruists" benefit other individuals but not themselves; kin selection does not seem to be a sufficient explanation of nonreciprocal altruism. Nonmathematical (but mathematically acceptable) models are now proposed for evolution of negative altruism in dual-determinant and of positive altruism in tri-determinant systems. Peck orders, territorial systems, and an ant society are analyzed as examples. In all models, evolution is primarily by individual selection, probably supplemented by group selection. Group selection is differential extinction of populations. It can act only on populations preformed by selection at the individual level, but can either cancel individual selective trends (effecting evolutionary homeostasis) or supplement them; its supplementary effect is probably increasingly important in the evolution of increasingly organized populations.

Interconnected patterns of biogeography and evolution.

Analysis of the fauna of the carabid beetles of New Guinea reveals both a broad dispersal pattern and a local turnover pattern that together fit into a world-wide pattern of successive dispersals and replacements that run from large to small areas and from more to less favorable climates. This pattern coincides broadly with a world-wide pattern of species numbers. Evolution by group selection, proceeding most rapidly and effectively where species are most numerous, connects the patterns and can supply the force that gives direction to the dispersal pattern. Directional change at any level of complexity involves movement that results in the formation of diverse groups of units (which are themselves groups of smaller units) and differential survival. This process-generalized group selection-has been continuous from chemical evolution on the earth's surface, through the origin of life, and into successive interacting levels of organic evolution. A corollary is that evolution should make situations favorable to itself, by group selection, and has probably done so in (for example) tropical rain forest, where new information about group evolution may be sought.