The OCR GCSE Biology Paper 2 (June 2019) covers ecological topics, including the water cycle, food chains, selective breeding, and genetic modification. It delves into biodiversity, trophic levels, and adaptations in ecosystems. Key themes include practical methods like capture-recapture, and experimental design in salt marshes. Additional focus areas are genetic inheritance, antibiotic resistance, and the impact of human activities on food security and disease control. Ethical debates around genetic engineering and the management of pests are also explored, emphasizing the integration of theoretical and applied biology.