1.1. To maintain biodiversity by preventing the extinction of species
1.2. For scientific research
1.3. For economic purposes
1.4. To maintain a stable and balanced ecosystem
1.5. To preserve natural scenery and wildlife for people to appreciate
2. Conservation measures
2.1. Idea 1
2.2. Idea 2
2.3. Idea 3
3. Effects of deforestation
3.1. Soil erosion: When trees are removed, the soil is directly exposed to the force of the rain. The topsoil, the most fertile layer is eroded during heavy rains, especially if the rain falls on steep slopes. Soil erosion can lead to flooding.
3.2. Flooding: The eroded soil may be deposited in rivers and streams, blocking the flow of water. The water levels in rivers rise rapidly, causing floods.
3.3. Desertification: When forest are cleared, the leafy canopy of trees no longer exists, sunlight falls directly onto the soil. Water evaporates rapidly from the soil, causing it to harden. The land becomes barren and plants cannot grow in the soil. The survival of organisms that depend directly or indirectly on plants for food are also threatened. Desertification results in habitats being lost and the extinction of many species of organisms. Overgrazing by animals can also lead to desertification because the plant are not able to regenerate fast enough.
3.4. Climate change: Rainwater that is retained and absorbed by the roots of trees is lost as water vapour during transpiration. The water vapour eventually condenses and falls as rain. When trees are cleared, there are fewer clouds, less transpiration and less rainfall. The area becomes dry and warm, and annual rainfall decreases.
4. Causes of water pollution
4.1. Untreated sewage/ Fertilisers: Contains diseases-causing organisms such as bacteria. Contains nutrients such as phosphates and nitrates, which are nutrients for algae and water plants, leading to eutrophication which leads to algae bloom, rapid bacteria growth, death of organism due to lack of oxygen
4.2. Inorganic waste: Waste water containing poisonous metals is discharged into the water body. Poisonous metals are absorbed by the water plants in the water body. The water plants are eaten by fish. Villagers who eat the fish are poisoned. Fish caught from the sea contain high concentrations of poisonous metals.
4.3. Insecticides: Destroy crop plants, transmit diseases. If insecticides are carried by rainwater into streams, rivers and lakes, they can accumulate in high concentrations in the bodies of aquatic organisms such as fish. DDT (dichlorodiphenyltrichloroethane) is an non-biodegradable insecticide. It remains in the soil or water for many years. Since DDT is insoluble in water, it is not excreted. Instead, it is stored in the fatty tissues of organisms rhat consume it. It accumulates in the bodies of consumers which results in bioaccumulation. Resulting in bioamplification or biomagnification (insecticide being passed along food chains, increasing in conc in the bodies of organisms along the trophic levels.
