Learn the key concepts of Environment and Ecosystems for O/L Science, explained simply
About O/L Science: O/L Science integrates physics, chemistry, and biology into a single subject across Grade 10 and 11.
The environment encompasses all living (biotic) and non-living (abiotic) components that interact in a given area. Human activities have significantly altered the environment — particularly through pollution, deforestation, and greenhouse gas emissions.
Pollution types: air pollution (burning fossil fuels → CO₂, SO₂, NOₓ causing acid rain and climate change); water pollution (industrial discharge, agricultural runoff with fertilisers → eutrophication); land pollution (plastic, chemicals). The greenhouse effect: certain gases (CO₂, CH₄, water vapour) trap outgoing infrared radiation, warming Earth — an enhanced greenhouse effect drives climate change.
Conservation strategies include biodiversity protection, reforestation, renewable energy transition, waste reduction, and sustainable agriculture. Sri Lanka's biodiversity is of global significance — the island hosts many endemic species.
Source: NIE O/L Science Grade 11 — Unit 7: Environmental Science and Conservation