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Lessons > The Producers > For Your Consideration

When the ecosystem contains plants only, one species of plant out-competes the other(s) and takes over. This illustrates the "competitive exclusion principle," which theorizes that no two species can occupy the same niche at the same time in a particular locale if resources are limited. (You can read more about this in the Unit 4 text.) The presence of a consumer is needed to keep that plant in check and allow the other species to survive.

The primary colonizers of an ecosystem, the producers, are also the harbingers of primary succession. As these pioneer plants die and decay, they add organic material to the soil, which, over time, will allow for secondary succession—generally larger and more delicate producers such as trees.

From what you have learned in the text and videos, how are humans contributing to the creation of a vastly rapid form of succession? In other words, how are we speeding up the effects of the competitive exclusion principle and thereby altering the outcome of that ecosystem's natural succession?

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