Living beings also modify the landscape, sometimes slowly and almost imperceptibly, and sometimes quickly and violently.
The upper floors, which have roots, exert an intense work is mechanical excavation of the substrate, in search of water. But, although less visible, erosion caused by small plants and organisms, such as lichens, is also important.
They also erode the animals. Small invertebrates, such as worms, aerate the ground and allow water to enter the mother rock. There are microorganisms whose secretions chemically attack the stones. Finally, superior animals can dig and erode in many different ways.
The action of vegetables
The upper floors, which have roots, exert an intense work of mechanical excavation of the soil, in search of the water they need for their subsistence. Some of these roots are able to pass through soft rock substrates or even break harder ones.
But, although less visible, the work of other plants and organisms, such as lichens, is perhaps even more important, to the point that they are considered the true indicators or pioneers of soil formation. Indeed, lichens act on bare rocks, begin their decomposition and allow other larger organisms to continue the task.
The animal's action
Small invertebrates such as worms and some insects aerate the soil, but also contribute to the process of weathering the mother rock by allowing the entry of air and water, as well as microorganisms producing secretions that chemically react with the rock, transforming and eroding it.
The work carried out by animals is, in general, complementary to that carried out by other erosive agents in the primary stages of the weathering process. However, it has a very important importance in the formation of soils.
The animals exert a mechanical erosion with the excavation or construction of nests and burrows, as well as the passage of large herds along the same paths. They also exercise control over the plant population they feed on. Finally, they produce secretions and excretions of materials that have a high corrosive power and can decompose the rocks, facilitating the action of other agents.
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