BIO 111

The Scope of Ecology

The first unit studied deals with the principles of ecology. Ecology is a term coined from the Greek oikos, which means home, and the Latin and Greek roots of our word logic, which refers to scientific study or thought. Literally translated it is the study of the home. When first described in 1869 by Ernst Haeckel this new science dealt with the study of the relationships between an organism and its environment. At the time, in the wake of the Darwinian revolution in biology, emphasis was placed on the specific characteristics each organism had evolved to in order to be successful in its habitat. About one hundred years later Hans Krebs led a new group of ecologists who looked at groups of organisms organized into populations and communities. They defined the science as the study of the relationships which determine the distribution and abundance of organisms. These population and community ecologists were establishing the dynamic nature of the relationships that organisms and species have with one another. More recently ecologists have recognized this dynamic set of relationships in the existence of the ecosystem and the biosphere. Called systems or global ecologists, they look for cause and effect relationships in what happens within ecosystems and within the biosphere.

Today ecologists representing each school of thought continue to look at the evolution and adaptation of organisms, how species and organisms relate to one another and to the environment, and the nature of these relationships and the systems to which they belong within the biosphere.

The levels described above represent the hierarchy of ecology, an extension of the hierarchy of life which you learned in general biology. The hierarchy of life stipulates the all living organisms are composed of cells, organized into tissues, organized into organs, organized into the organism.

Ecology represents an extension of that hierarchy:

The functions studied can be summarized in the word homeostasis. Homeostasis represents the many balances seen in ecosystems and the biosphere, and can be define as the dynamic balance of processes, materials, and organisms. Processes such as photosynthesis and metabolism are balanced, materials such as oxygen and carbon dioxide, nutrients and waste are balanced, organisms such as predators and prey are balanced. Homeostasis is also the ability to respond to stress to maintain balance. Stress can be natural such as fire, drought, flood etc., or human-caused such as pollution. Ecosystems are inherently adapted to naturally occurring stresses, and can adapt to human-caused stress when the stress is not extreme or prolonged. But the adaptations may not be desirable for man. The challenge of ecology is to predict what these adaptations to stress will be, and how to mitigate the impact of stress on the environment.