The Science of Ecology Organisms in the biosphere interact with each other and with their surroundings, or environment. The study of these interactions is called ecology. Ecology is the scientific study of interactions among organisms and between organisms and their physical environment. The root of the word ecology is the Greek word oikos, which means “house.” So, ecology is the study of nature's “houses” and the organisms that live in those houses.

Interactions within the biosphere produce a web of interdependence between organisms and the environments in which they live. Organisms respond to their environments and can also change their environments, producing an ever-changing, or dynamic, biosphere.

Ecology and Economics The Greek word oikos is also the root of the word economics. Economics is concerned with human “houses” and human interactions based on money or trade. Interactions among nature's “houses” are based on energy and nutrients. As their common root implies, human economics and ecology are linked. Humans live within the biosphere and depend on ecological processes to provide such essentials as food and drinkable water that can be bought and sold or traded.

Levels of Organization Ecologists ask many questions about organisms and their environments. Some ecologists focus on the ecology of individual organisms. Others try to understand how interactions among organisms (including humans) influence our global environment. Ecological studies may focus on levels of organization that include those shown in Figure 3–1.

In Your Notebook Draw a circle and label it “Me.” Then, draw five concentric circles and label each of them with the appropriate level of organization. Describe your population, community, etc.

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