4 Ecology and the Environment¶
This topic area moves outward from organisms to ecosystems. It connects populations, feeding relationships, material cycles and human environmental impact into one ecological picture.
Core Role¶
- Define the main ecological levels of organisation and the factors that affect them.
- Explain how substances and energy move through food chains and food webs.
- Connect biodiversity and environmental change to human decisions and conservation choices.
Topic Pages¶
- 4a The Organism in the Environment: Ecology begins by naming the levels at which organisms interact with their surroundings. It then moves into ways of measuring populations and biodiversity in real habitats.
- 4b Feeding Relationships: Feeding relationships show how matter and energy move through ecosystems. The main emphasis is on trophic levels, the meaning of food chains and food webs, and why only a small fraction of energy is transferred onwards.
- 4c Cycles within Ecosystems: Matter is continually recycled through ecosystems rather than used once and lost. The important cycles here are the carbon cycle and the nitrogen cycle.
- 4d Human Influences on the Environment: Human activity can alter ecosystems by changing gases, nutrients, water quality and land cover. The topic is mainly about tracing cause and effect from human action to biological consequence.