Effects of Human Activities on Ecosystems – S5 Biology Notes

These teacher-prepared Senior 5 Biology notes look at how human activities change ecosystems. They start with an overview of the effects, including biodiversity loss, pollution, soil erosion and global warming. The notes then explain pest control in detail: cultural, chemical, biological and integrated methods. They cover the toxicity, persistence and specificity of pesticides, how DDT builds up along food chains, and pest resurgence, with a worked calculation example. Later sections describe the causes and effects of deforestation and the positive and negative effects of agriculture on ecosystems. The notes are useful for advanced-level classroom study and revision.