List out of how animals and plants can cause weathering. Plants
The Correct Answer and Explanation is:
How Plants Cause Weathering
Plants play an important role in the process of weathering, especially in the breakdown of rocks and minerals on the Earth’s surface. The weathering caused by plants can be divided into physical and chemical weathering. Here’s how they contribute to each:
1. Physical Weathering:
Plants contribute to physical weathering primarily through the process of root growth. As plants grow, their roots penetrate into the cracks and crevices of rocks. Over time, the roots exert pressure as they grow larger, which can cause the rocks to fracture and break apart. This type of weathering is known as root expansion weathering.
- Example: Trees growing in rocky areas like mountains or along cliffs will have roots that push into rock fractures, slowly widening them. This can cause large chunks of rock to break off over time.
- Freeze-thaw action: Another related aspect is the freeze-thaw cycle. When water enters these cracks, it can freeze and expand. The plant roots can help retain moisture in these cracks, further enhancing the weathering process.
2. Chemical Weathering:
Plants also contribute to chemical weathering through the secretion of organic acids. The roots of plants release weak organic acids, such as citric acid and oxalic acid, which can react with minerals in the rock. This can break down the rock’s mineral composition, turning hard rocks into softer, more easily weathered materials.
- Example: Lichens and mosses, which often grow on rocks, also produce organic acids that slowly break down minerals like calcium carbonate. This process is especially important in the weathering of limestone and marble.
- Soil Formation: The breakdown of rock due to plant-induced weathering contributes to soil formation, which in turn supports further plant growth, creating a cycle.
In conclusion, plants cause weathering through both physical mechanisms (root expansion) and chemical mechanisms (organic acid secretion), both of which break down rocks and minerals over time. This process is critical for soil formation, which sustains plant life and helps shape the landscape.
