Ecology: An Evolutionary Approach [antikvár]

PrefaceNever before in our history has it been so vital that we understand and intelligently oversee the use of our environment. We need to know in detail the effects on biological productivity and relationships of adding chemical effluents to our streams, lakes, and oceans; we need to know the effects of diminishing numbers of species on the stability of remaining populations, including our own; we need to understand how our own evolutionary heritage predilects us to certain behavior patterns. The most urgently needed knowledge perhaps involves the relationships within whole biological communities, and it is precisely these relationships about which, unfortunately, we probably know the least.The reason we know so little of biological communities is fairly straightforward. For one thing, communities are terribly complex. But it is more than that. The understanding of biological principles comes through the meticulous building of knowledge and statement of laws, starting from the simplest axioms. Such axioms are few in biology and take one of two forms. They are either the laws of chemistry and physics, or the laws of evolutionary change. Ecology, the study of organisms in their environment, starts from both.Limnologists, for example, base their conclusions largely on the first, while evolutionists rely on the second. Accordingly, practitioners of these two disciplines may look on the same ecological questions from very different viewpoints. To a limnologist a creature encysts, perhaps, because of pH, temperature, or chemical changes in the environment. To the evolutionist the creature encysts because, in the past, those ancestors which possessed genetic material predilecting them to encyst under the appropriate conditions more often survived to pass on that genetic material than individuals which possessed other genes. The approach of the limnologist is mechanistic, or proximate-, that of the evolutionist ultimate. Both approaches are equally valid and, in concert, very fruitful. But the secondand to a large degree also the firstapproach applies to individual adaptations to the environment. To apply it to biological communities without falling into the dangers of argument by analogy, we must first look at individual adaptation, then apply what we learn of individual adaptation to population changes and interactions, and finally apply this last knowledge to communities. Community ecology is the field of ecology farthest removed from the basic axioms available, and hence is least thoroughly understood.Most of what we know of ecology is of an empirical nature. In the past, faced