Rocks shape life around them. Animals may use rocks as a home or hiding place from predators. A large number of rocks may make plant life difficult to take root, but it also provides a place for moss and lichens to grow. Animals in rocky terrain have adapted with strong, agile legs. For example, a mountain goat is well-suited to living in high, rocky altitudes and uses its speed and agility to run from predators.

The kind of rocks and soil in your neighborhood or anywhere else in the world depends on a lot of factors. These factors include abiotic ones such as weather and topography. However, it also includes biotic factors such as plant and animal life. Therefore, soil affects plant/animal life, and plants/animals affect soil.

Soil also affects plant life. Moist or damp soil means that plants have shallower roots, because they don't have to go very far to find water. In contrast, soil in desert areas generally mean that roots have to reach far down into the soil to get water. Nutrient-rich soil may mean more plants per square foot than areas with low-nutrient soil.

The soil profile is the surface of the soil layer extending downward to its deepest layers. There are many horizons (layers), each of which has its own characteristics in terms of mineral content, nutrients, color, and texture. The texture is important because it determines how much water the soil can hold. The layer closest to the top is called the A horizon. The A horizon is made of organic material and minerals. The B horizon is found beneath the A horizon. The B horizon is where most of the minerals that make up the soil, such as calcium and magnesium and iron are found. The C horizon is the deepest layer and contains partially weathered bedrock material. The following interactive lesson describes the different types of soils and their locations on Earth.




Source: Teachers' Domain, Soils Around the World, published December 17, 2005, retrieved on July 11, 2010, http://www.teachersdomain.org/resource/ess05.sci.ess.earthsys.soils/