Natural Resources: Management, Environment and Our Environment
Natural Resources tests management of natural resources, environment and our environment, with sustainability, ecosystem and pollution reasoning.
Resources and sustainability
Natural resources are renewable (sunlight, wind, water, forests) or non-renewable (coal, petroleum, minerals). Sustainable management uses resources without damaging the ability of future generations to use them. The three Rs are reduce, reuse and recycle. Forests conserve soil and water, support biodiversity and influence rainfall; deforestation causes erosion, flooding and loss of habitat. Water harvesting, check dams and watershed management recharge groundwater. Fossil fuels are finite and release CO₂, contributing to the greenhouse effect.
Environment and ecosystems
An ecosystem includes biotic and abiotic components. Food chains show energy flow; arrows point from the eaten to the eater. Only about 10% of energy passes to the next trophic level, so food chains are short and top carnivores are few. Pollutants can biomagnify. Ozone in the stratosphere absorbs ultraviolet radiation; CFCs deplete it. Greenhouse gases trap heat. Waste management means segregation, composting, recycling and safe sewage treatment.
Worked example
A grassland producer level contains 10,000 J of energy. Using the 10% law, herbivores receive 1,000 J, carnivores 100 J, and top carnivores 10 J. This explains why large top predators need huge areas and why a food chain rarely has more than four or five links. The loss at each step is mainly heat from respiration. Biomagnification is different: a non-biodegradable pollutant becomes more concentrated at each higher level.
Traps
The ozone hole and global warming are separate problems: ozone depletion is caused by CFCs; warming is driven by greenhouse gases. Renewable does not mean unlimited; overuse can exhaust groundwater or forests. Arrows in a food chain show energy flow, not backwards feeding. Biodegradable waste can still pollute if it overloads a system.