life

The soil of an area provides the foundation for plant and animal development. Areas that have not yet developed plants tend to have poor, hard, or shallow soil. As plants begin to develop, soil tends to improve.
As soil conditions change, different communities of plants and other organisms may develop over time in a single area. This sequence of communities is called ecological succession. Succession generally follows one of two patterns. Succession is said to be primary if it occurs in a habitat that initially has no soil or organisms. An example of such a habitat is a lava field after a volcanic eruption. Succession is secondary if it occurs as a result of a disturbance. An example of such a disturbance is a forest fire that does not destroy the soil.
The plant species tend to succeed one another in patterns related to factors such as competition for soil and light. The pioneer plants, which develop first, must have the kinds of roots and other adaptations that allow them...