"In an ecological context it is almost a gratuitous reaffirmation
of faith to note that any individual organism or single-species
population of organisms exists not in isolation, somehow separable from
the complexity of interactions around it, but as an integrated
component within a complex ecological 'whole' - one part only of an
intricate mechanism of interdependent, individually moving parts"
". . . constellations of species can be viewed as evolving together within a conventional Darwinian framework" (May, 1978).
". . . no modus procedendi can be correct which does not attempt to understand those principles and the interactions of the conflicting interests of all participants" (Von Neuman & Morgenstern, quoted in Dennett, 1995).
"In a universe of electrons, blind physical forces and genetic replication, some people are going to get hurt, other people are going to get lucky, and you won't find any rhyme or reason in it, nor any justice. The universe that we observe has precisely the properties we should expect if there is, at bottom, no design, no purpose, no evil, no good, nothing but pitiless indifference (Dawkins, 1995)."
"Looking at this philosophy (of the Tao) with the needs and problems of modern civilisation in mind, it suggests an attitude to the world that must underlie all our efforts towards an ecological technology. For the development of such a technology is not just a matter of the techniques themselves, but of the psychological attitude of the technician" (Watts, 1975).
"All things have each their own different principle, whereas Tao brings the principles of all things into single agreement" (Watts, 1975).
Ecosystems are functional units within which animals interact with their physical environment and each other. Emphasis upon the physical environment is important so differentiate an ecosystem from a community. An ecosystem consists of the community plus its habitat. A community of organisms is an assemblage of interacting species and the various interrelationships that bind them. Evolution occurs in an ecological context namely the ecosystem.
Evolutionary biologists are interested in the cause of natural mechanisms. Food chains linking organisms, bind each into this interdependent community or ecosystem. Green plants in their diversity, form the bottom of the food chain. Using the sun's radiant energy, carbon dioxide from the air, and water and nutrients from the soil, plants produce energy rich sugars and other tissues. As a by-product of the process plants release oxygen into the atmosphere.
In the development of this book, the intensity of interactions has proven to be of crucial importance. This intensity is expressed as an energy value. In the ecosystem context, this interaction can be with the biotic (living) and abiotic (nonliving) environment. Interactions can also occur between individuals within a population ( intraspecific ) and between individuals of different species ( interspecific ). Intraspecific interactions will prove to be crucial to speciation (species formation).
For Ultra-Darwinians, natural selection centers on the perpetuation and maximization of the individual’s genes within the population. They define fitness as reproductive success, with economic success serving this purpose. Dawkins claims that organisms are mere vehicles and that the true replicators competing for reproductive success are the genes.
Naturalists such as Aldredge see large-scale systems, species, social systems and ecosystems "as absolutely crucial to understanding how the evolutionary process actually works." As a paleontologist , he repeatedly found (empirical) evidence that once species appear in the fossil record, they do not then change much, a phenomenon he termed stasis. This observation did not fit the models of the Ultra-Darwinians. Perpetuity and compatibility as a holistic theory explains this stasis. Perpetuity is the drive or impulse to survive , and compatibility is the constraint that results from the dependence of a species upon a system and interdependence of associated and interacting species.
Reproduction gears animals to produce variations of the phenotype (physical form). These varieties will cluster around some value at which fitness is highest. As variation diverges from an apparent mean optimum, mortality rates increase.
A simple formula illustrates this trend:
I = (So - Ss)*fs
where I = selection intensity or pressure,
So = survival rate of optimal phenotype,
Ss = survival rate of suboptimal phenotypes,
fs = the frequency of suboptimal phenotypes.
When the selection pressure is zero, all the phenotypes are optimal. At fs = 1, all the phenotypes are suboptimal. This formula is again a model, one of many that may reflect the real process. It reflects how adaptation through natural selection takes place and its beauty lies in its simplicity. A departure from the optimum phenotype leads to lower survival rates. The above formula is a useful tool for understanding and illustrating natural selection.
People of the Jewish and Christian tradition mostly see nature as an exploitable resource that they can manipulate according to human whim and fancy. This is in accord with the belief of Man having "dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creepeth upon the earth" (Gen1: 26).
An aim of the holistic approach is to find common denominators of structure or organisation . From this we arrive at sound principles of organisation and a method of rationalisation of complexity . Ecosystems have a dynamic quality; the process described in traditional ecology as ecological succession , or today, simply, succession. Evolution results in the adaptation of associated species to each other and the rest of the environment, so that the community shows precise adaptation to its "preferred" (adaptation to the system of association) or natural habitat. In the whole system, an organism's role or niche is simply that in which it is found - they have evolved that specific ecological role through their evolution with the whole ecosystem. Science, until today, has been based upon the study and analysis of parts of the system. There is obvious value in the reductionist method of studying units of the whole, but scientists have to balance this with recognition of the need to identify patterns and processes that characterise the whole system.
Researchers derive many ecological principles from laboratory studies . These conditions neither fully duplicate the niche, nor the ecosystem to which the animal is adapted, so they usually result in mechanistic cause and effect or stimulus-response results. These will not show what really occurs in nature, nor the idea of compatibility. To perceive and understand the interdependence and holistic integrity of natural complex systems, they must examine nature in the field. Researchers can accommodate neither the ecosystem's "response" and corresponding individual's behavioural response, nor the immense period of evolutionary historyin a laboratory experiment.
With the domination of the ideas of 'survival of the fittest' and competition, to describe natural processes, there is little chance of perceiving nature's dynamism in terms of the principle of compatibility. A species in decline due to the "competitive" (interactive) effect of associated species, can respond through three mechanisms:
i] either it increases its reproductive rate (r-factor), ii] or it increases its competitiveness (c-factor) or interactive effect upon the associated organism effecting the decline,
iii] or it reduces the interactive effect (i-factor) incurred upon it by the other species through any possible mechanism.
The third mechanism is the source of the mechanism leading to speciation or species formation. Instead of the confusing term "competition" one should speak of the relative intensity of interactions (i-factor) . It is the intensity of interactions that determines the intensity of the selective pressure and thus the rate of evolution. Through this reduction of interactive "costs", the individual becomes more efficient and therefore relatively more effective. Its relative fitness increases. Natural selection leads to a reduction in "costs" through an optimisation process. Most cases of species formation are the result of the animal's response to biotic selective pressures by evolving to reduce the interactive cost between it and associated animals.
Geneticists often explain co-operation as the result of shared genes and reduce the unit of natural selection to the gene. Modelling with the modified energetic Lotka-Volterra model ( MELV model) shows that natural selection can lead to coadaptation between unrelated interactors due to the selection of economic factors that operate within the ecosystem at the individual level. A decrease in the interactive cost through natural selection is a relative economic factor. The evolution of coadaptations is the result of the evolution of improved economic efficiency!
Game theory is about perfectly logical players interested only in winning. In ecological terms, it is about survival through competition and in holistic terms, it is about perpetuity. It is essentially competitive. What is missing from these calculations is the impact of the interaction upon the whole system, and the relative fitness of the interactors (achieved through natural selection). This is the compatibility factor. Interactions in ecosystems are more complex than the applications of game theory because the "players" affect the environment upon which they depend. The perpetuity-compatibility (p-c) idea considers the whole environment. Game theory seeks the optimal resolution of a conflict, while the p-c idea leads to the avoidance of conflict behaviour as far as possible.
Fundamental science, based on the urge to know more about nature and us is shifting its emphasis. Research organisations are abandoning basic science, or research for its own sake in favour of applied goals. A shift in emphasis to applied science, after the past 100 years of exploration and discovery, has some important implications. It is a form of adaptation through specialisation, building a dependency upon technological innovations. Society is turning to science to solve environmental and other problems through technological fixes. In terms of the principles of natural selection we are becoming more specialised. Being specialised, we are becoming more dependent upon technology for our survival and less able to adapt. Instead of forcing our way through with genetic engineering, biotechnology, nuclear fission reactors, deadly chemicals and the total replacement of ecosystems with highly mechanised and heavily fertilised monoculture-type agriculture, we need to learn nature's constraints and adapt our lifestyles to these conditions. In effect we need to despecialise while maintaining educational and living standards as high as possible. We need to harness nature's forces, placing humanity central to ecosystem processes.
The weather represents an inert dynamism and an associated species an evolving dynamism. It is the evolving dynamism of living creatures that has led to the idea of progress in nature and evolution so vehemently opposed by many scientists. An organism interacts not only with other species (interspecific), but also with its own kind (intraspecific). With increasing biotic diversity and complexity follows increasing biotic interactions . The Cambrian era marks the beginning of the intensification of biotic interactions. Since then, coevolution has been taking place as animals evolve strategies to counter the interactive effects of associated organisms. An animal becomes adapted to a habitat that consists of biotic and abiotic influences.
If two species occupy the same niche, ecologists say they are competing for the same resources. Competition for a resource such as food is a biotic selective pressure. To exclude a species, another species must actively use some niche component. A species may also perish if some component is not present or is not accessible. Biotic selective pressure is a more objective term than the anthropomorphic "competition" when discussing interactions. Organisms interact with their living (biotic) and nonliving (abiotic) environment.
Mobility allows behavioural responses to both abiotic and biotic influences, so an animal may seek shade during the heat of the day or flee from a predator. Physical adaptations are also possible to both biotic and abiotic influences. Gradations of this response to predatory pressure can range from physical to physical-behavioural such as where the potential prey releases a bad odour to fully behavioural such as flight into an inaccessible hole.
Another form of biotic interaction occurs in nature, defined in terms of perpetuity and compatibility. To survive, the animal has to perpetuate its kind through reproduction. Individual survival is the first requirement, reproductive success of individuals the second. Traditional Darwinian evolution defines the creature that passes its genes onto the next generation in greater numbers as the fittest. I will show that we may we find something different and may call it eco-fitness . An organism's perpetuity requires the habitat to which it is adapted. Maximising numbers in the next generation can quickly degrade the environment through pollution and denudation, so is a short-term remedy, perpetuity without the necessary compatibility. Perhaps all extinctions occur due to changes to an organism's habitat. If rapid change threatens an ecosystem, the species dependent on that ecosystem may also become extinct.
Changes at the level of the gene (genotypic changes within the nucleus) are reflected in changes of the phenotype - behaviour, physiology and anatomy. Natural selection is reflected as a change in the gene frequencies within the population. The most obvious mechanism by which animals "on their own initiative, make density-dependent responses to changing conditions" is territoriality . Another form, social hierarchies , may be found in gregarious animals that form concentrations of animals such as in herds. A fundamental feature of these various mechanisms is that they increase the intensity of intraspecific interactions .
Territoriality is a behavioural strategy that enhances habitat stability and excludes the "cheaters". It reflects the animal's evolved behaviour ("strategy" to "regulate" its population) so that it does not detrimentally alter the habitat to which it is adapted and upon which its survival and the survival of its offspring depends. An organism's survival depends as much upon the perpetuation of the habitat to which it is adapted and the niche that it occupies, as it depends on individual fitness and reproductive success. An organism is only fit within the context of its habitat. Convergent evolution has led to territoriality repeatedly in a whole range of life forms and from the very beginning of life. Territoriality provides an intense interactive mechanism used to sort out the fitter of the population that will mate and contribute to the next generation.
Considering absolutes, the less influence an animal has on a habitat, while still able to survive, the greater its survival potential and compatibility. The biotic component of the ecosystem provides a negative feedback to the interacting species. A territorial animal maintains an area big enough to feed itself and its young and thus perpetuate, without depleting its food resource, so forming a unit of stability. Abiotic environmental fluxes (temperature etc.) remain density independent and animals have to adapt to them when necessary.
An animal can have a negative influence upon the stability of an ecosystem, it can have no effect upon the ecosystem at all, or it can affect the ecosystem in a positive, beneficial way.
If two or more species interact, using the same limiting resources, then natural selection will favour the evolution of interspecific interactions with less mutual effect than intraspecific interactions . Organisms adapt to the conditions and constraints of their environment. Solutions in nature are necessarily economic as greater efficiency can be a selective advantage. When many species interact, perpetuation of the species does not result in the evolution of interspecific competition, but the tendency for the evolution of interspecific compatibility, so that interacting species have less effect upon one another than do the average of intraspecific interactions . Ultimately the energetic costs or intensity of intraspecific interactions must drive the process, as fitness is a relative value.
We must recognise the many constraints upon natural systems, such as intrinsic growth rates, environmental carrying capacities and predation rates. Biological systems are full of natural constraints and different associations. We need to explain nature by reference to her and her own standards, thereby to some extent eliminating or at least reducing the subjectivity of our perceptions. The principle of perpetuity needs to accommodate the stability of the habitat upon which the animal depends - thus compatibility .
1. ECOLOGICAL INTERACTIONS: MODELLING COMPATIBILITY.
A population's rate of change (dN/dt), or the change in numbers of a population (N) with time (t) is expressed as follows:
dN/dt = rN
where r is the intrinsic rate of increase of the population (N). Environmental carrying capacities for a species represent the maximum population size that the habitat can support sustainably and indefinitely. An animal's habitat is limited, so as the population grows, the increased density begins to limit or inhibit growth in some way until zero growth, an asymptotic level called the carrying capacity, reached. To introduce this limit to growth, the carrying capacity of the environment, we use a different equation. This model is the Verhulst-Pearl equation:
dN/dt = rN -----
As the species numbers (N) approaches the carrying capacity (K),
the top half of the equation approaches zero and the rate of growth
approaches zero. This is the logistic growth curve. The population
levels off to a plateau, a situation better reflecting the real
situation in nature.
With modification the equation becomes:
----- = r1N ---------------------
Of the variables in this formula, the competition coefficient , alpha (i12) , is the most important. I shall call it the interactive coefficient (i or i-factor) to accord with the compatibility concept and allow the consideration of all interactions, including competition and cooperation.
The competition coefficient (alpha) represents the strength of interaction, showing the extent to which its association with species 2 influences the growth rate of species 1 (Putman, 1994). i12 is the interactive effect of species 2 on species 1 . We give INTRASPECIFIC interactive effects, represented by the i-factor, or the "cost" of the interactive effect of two individuals of the same species, the value of 1 and all other interactions with other species are measured RELATIVE to this value. In other words the average interactive effect of two individuals of the same species has a "cost" of 1.
If, in the interspecific interaction, i12>1 then individuals of species 2, perhaps a lion, have on average a greater inhibitory effect on individuals of species 1, the wildebeest, than do the individuals of species 1 upon themselves. It is easy to see that in wildebeest, this value has to represent an average for the population as male-male interactions may be more aggressive than female-male interactions and each individual interaction may be different. Further, the formula requires that each consideration in determining the i-factor be strictly between the two species involved so that such i-factors relate to that specific interaction and cannot be compared directly.
As interactions diminish, the animals reach a point of no interaction. Where two species do not compete, the i-factor becomes zero. At this point the two populations do not affect each other, so their carrying capacities are independent of one another.
Multiplication of N2 by i12 (the effect of species 2 on species 1) brings the population N2 into relation with population N1 as concerns their relative interactive effects. If the presence of N2 individuals has the same average effect upon N1 as does other N1 individuals, i12 is 1. Compatible (cooperative) behaviour results through natural selection at the level of the individual, because compatible behaviour in its many forms is the fittest possible survival mechanism. The evolution of reduced interactive effects between associated organisms leads to the most stable organisation.
Maximised reproductive output leads eventually to overpopulation of the reproducer. Ecological instability results, negatively affecting the reproducer. In this model, the animal acts purely in self-interest. However, natural selection has defined this "self-interest" or perpetuity in the animal's interactive realm, which is the whole ecosystem. In this holistic ecological context, compatibility becomes a component of "self-interest" (perpetuity), in "selecting" for ("deciding") the fittest through the process of natural selection. Cooperating units evolve naturally within the complex organisation of the system, but with the individual still acting to best maximise the perpetuity of its own kind. That the behaviour selected for is cooperative is a consequence of its superiority over the long term as displayed by the MELV model .
Adaptation, when between organisms that are both evolving,
leads to what appears like group selection, but is coadaptation.
The conclusion drawn from the model is that behaviour that reduces the
interactive effect or "cost" between individual organisms of the same
or different species, is selected for through natural selection, as
such behaviour leads to both ecological stability and individual
Natural selection decreases the intensity of interaction between two associated species through their diversification, as this is an economic advantage. Specialization and diversification are an adaptive advantage, improving survival potential. The mechanism of such specialisation and diversification will be similar to that which adapts some invertebrates to the annual change of its food resource, so that they have evolved a period of growth and a period of dormancy . Similar too is the stimulus to migrate found in some birds.
I have interpreted the relationship where, for both species, intraspecific competition inhibits the growth of populations more than interspecific interactions as an association of interdependence . I have recognised the evolution of interdependence and coadaptation.
An i-factor of zero implies no interaction or no measurable impact in one direction of the interaction. The intensity of the intraspecific interactions, measured in energy terms has a value of 1. We compare all other interactions with this. Between 0 (no interaction) and 1 (interactions equal to intraspecific interactions) exists the realm of coadaptation, if both species have an i-factor of less than 1 for the other species. This is the window of opportunity that nature uses and leads to holism. This is what I model and is the source of compatibility.
The formula restricts one strictly to a consideration of INTERACTIVE EFFECTS or the interactive regime between the two species. Niche separation may be so that the two species depend upon completely different food resources, nesting sites etc. There would then be no interaction, the i-factor being 0 and the two K-values would be independent variables. If i is above 0 the two species interact and share some resource and their K-values must intersect to an extent.
Biotic relationships, under the conventional scheme of the Lotka-Volterra model, are represented by a competition coefficient, which is positive (+) if the interaction effects an increase to population growth and negative (-) if it effects a decrease to population growth or 0 if no effect is felt. As such, this method allocates ++ as the effect of the bee-flower interaction or mutualistic relationships, with both competition coefficients being positive and a predatory or parasitic relationship as +-. Conventionally, the model's e interactive coefficient is a measure of the effect of one species upon POPULATION GROWTH of another. This is difficult to quantify. My adaptation of this model defines the i-factor as a relative energetic cost. The i-factor determines the r-factor . Evolution through natural selection has defined intraspecific behaviour that is an adaptation to the environment and determines the reproductive output (r-factor) of the species. As natural selection selects for the fittest, and those that perpetuate are the fittest, what is found is fitness defined by the i-factor.
Interaction with one's own species gets a value of one, but represents the average energy expended through such interactions under normal conditions. This is a one to one interaction. WITHIN THE TOTAL SYSTEM THERE ARE MANY SUCH INTERACTIONS, THE NUMBER RELATED TO THE POPULATION DENSITY. This may give a clue as to the mechanism of self-regulation of the population density. An interaction is an energetic cost while the habitat provides an energetic return. They exclude weaker interactors when the effort to maintain intraspecific interactions uses more energy than the animal gains from its habitat. The adjustment can thus be a natural mechanism dictated by inherited behaviour determining interaction rates and intensities, the average energy expended to maintain daily activities and the return in energy as food. Without the intraspecific interactions the animal may have survived and had time to gather more food. Interactions may therefore lead to animals maintaining a population density below the carrying capacity of the environment.
By definition, an ecosystem's inhabitants evolve together, so natural selection will favour lower i-factors for each species within the ecosystem. This results through the coevolution of associated species. Lower i-factors mean greater energetic efficiency for the whole ecosystem and therefore greater stability. They have achieved a decrease in the i-factor of an organism experimentally.
Forces of natural selection shift because of the interactions between species that share niche space . Coadaptation occurs, as each interactor will be adapting to the other's presence. Holism emerges from the complex system as a result of interactions and natural selection.
As the environment changes, the species will track its required habitat and become extinct with the loss of that habitat. Evolutionary stasis is evident from the fossil record. Species remain unchanged for perhaps millions of years once formed. With this pattern there is a rapid evolution of new species before the period of stasis. As a result of this process, there is a glaring absence of transitional or intermediate forms in the fossil record. Geneticists cannot explain this with their models.
A part of the adaptive process resulting from evolution through natural selection of closely and long-associated species is a decrease in the i-factor of interspecific associations. The Lotka-Volterra model displays this. We must apply the same principle to intraspecific interactions that are subject to natural selection. A major difference here is that the gene pool is common to both interactors. As such, a decrease in the i-factor through natural selection is economically based. Individuals have higher fitness if they can be more efficient economically while still reproducing. With time this leads to greater efficiency and fitness for the species as a whole.
Economic factors come into play under the force of natural selection acting to decrease the i-factor. Variations from some economic norm are less fit and are therefore eliminated through natural selection. A species becomes a real entity maintained in a state of stasis through natural selection and reproduction. Once such an isolated subpopulation is founded, heavy forces of natural selection, shaping the necessary adaptation of the new or potential species, leads to the rapid rate of evolution at this early phase of speciation. Adaptation through natural selection brings the population into accord with its new environment. At this early phase of speciation, the population is occupying a new niche. Initially the struggle is for survival. A capable variant persists irrespective of its economic efficiency. At this stage survival needs override competition or economic efficiency. As time proceeds, intraspecific interactions lead to a decrease in the i-factor for the incipient species. As the animal becomes adapted to its new environment, the effect of intraspecific interactions increases in importance, so that after an initial, very rapid evolution the form of the species stabilises.
Go to next chapter: B. INTRODUCTION:
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