04 Feb Learn about deforestation and pollution from your science tuition teacher
When your science tuition teacher tells you to do a project on how human activities affect the environment, what is the first thing you will think of?
Human activities and interactions with the environment have improved living conditions, but some have caused substantial harm to environment and organisms. Major impacts include pollution. Pollution is the release of harmful substances and objects into the environment.
Deforestation is the major clearing of trees and vegetation in a land area for human use (housing, transport facilities) and wood for other purposes (e.g. producing paper)
Since forests are home to diverse range of organisms, deforestation makes their habitat unfavourable and unsuitable for them to live in
Many plant species will die Food chain is disrupted. Herbivorous animals will be affected (population may decrease due to lack of food). Animals relying on herbivores have less food. This leads to endangerment of species which may have medicinal values for curing diseases.
As plants, which takes carbon dioxide and replenishes oxygen during photosynthesis, are removed, carbon dioxide concentrations in the air would increase
Deforestation affects the water cycle. Plants absorbing water from soil and release it into air are removed. Hence, there will be less water vapour for cloud formation and rainfall.
As trees are removed, there are fewer roots to hold soil in the area. The soil is exposed to wind and water. The topmost layer of soil (rich in nutrients) is easily washed away by rain. This is called soil erosion. New plants are unlikely to grow in the area, landslides happen in the area become more frequently.
Deforestation sometimes carried out by burning forests. It releases smoke and harmful gases. It causes severe air pollution, respiratory problems in humans and uncontrolled fires spread to other places. This threatens the life of organisms. Science tuition classes will reinforce these concepts more easily and quickly.
In some countries, solid waste containing toxic substances is buried in landfills. This may easily seep into soil, contaminating land and killing organisms living in that area. Plants may absorb toxins and animals that feed on them may die. Rainwater may also wash these into water bodies and kill aquatic life.
Land also becomes polluted with increased volume of rubbish collected in landfills. Buried waste takes up place requiring new landfills if the current one becomes full, taking up valuable land. This is especially for plastics which is not biodegradable. Biodegradable means easily broken down by decomposers and bacteria.
Excessive fertilizers and pesticides used on crops makes land unsuitable for growing plants.
Major cause of water pollution is waste water from human activities – cleaning, cooking, manufacturing processes in factories. It may be toxic and can kill aquatic organisms consuming aquatic life. They absorb poison that accumulates in bodies of aquatic life.
Rubbish e.g. plastic bags, nets pollutes water if not thrown properly and ends up in water bodies; aquatic organisms may be killed due to entanglement with these objects or mistakenly consuming them.
Soil erosion may also cause water pollution as rain washes soil particles into water bodies and make them cloudy. Less sunlight is available for aquatic plants and they eventually die, killing animals that directly or indirectly depend on them.
Water pollution may also be caused by oil spills from tankers:
Oil spills stop oxygen from reaching underwater. Many aquatic life will die. Animals come in contact with spills. The oil sticks to them and removes air trapped by feathers and fur that help insulate them. In cold conditions, they die without the insulation.
Animals are poisoned as they swallow toxic oil when they try to clean themselves, causing disorders or even death.
Air pollution is caused by release of harmful gases from burning of fuels (vehicles, power station, factories), rubbish in incinerators and deforestation.
It is harmful to plants as the ability to photosynthesise is hampered.
Air pollutants such as ash, toxic gases combine with water droplets in air to form acid rain. It is harmful to organisms on land and in water. It also destroys buildings and monuments.
It causes breathing difficulties, eye irritations, respiratory problems in humans.
Toxic gases in air may be absorbed into bloodstream of animals and humans. There could be disastrous effects like lung cancers, organ failures and death. For example, lead particles from lead-containing fuels is extremely poisonous as it can cause severe brain damage in humans.