2015-10-13
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Life thrives in every environment on Earth, and each of those environments is its own ecosystem, a group of living and nonliving things that interact with each other in a particular environment. An ecosystem is essentially a little machine made up of living and nonliving parts. The living parts, called biotic factors, are all the organisms that live in the area. The nonliving parts, called abiotic factors, are the nonliving things in the area (think air, sunlight, and soil).
Ecosystems exist in the world’s oceans, rivers, forests — they even exist in your backyard and local park. They can be as huge as the Amazon rain forest or as small as a rotting log. The catch is that the larger an ecosystem is, the greater the number of smaller ecosystems existing within it. For example, the ecosystem of the Amazon rain forest also consists of the soil ecosystem and the cloud forest ecosystem (found at the tops of the trees).
A particular branch of science called ecology is devoted to the study of eco-systems, specifically how organisms interact with each other and their environment. Scientists who work in this branch are called ecologists, and they look at the interactions between living things and their environment on many different scales, from large to small.
The sections that follow explain how ecologists classify Earth’s various eco-systems and how they describe the interactions between the planet’s many species. Before you check them out, take a look at Figure 11-1 to get an idea of how living things are organized.
