Environmental Studies
- qualitative inheritance
- quantitative inheritance
- quantum evolution
- quantum speciation
- r-selection
- radar tracking
- radial symmetry
- radiation ecology
- radiation fog
- radioactive tracer
- Radiocarbon Dating
- radiolarian ooze
- rain-gauge
- rain-wash
- raindrop
- raised bog
- random sample
- random-walk technique
- range management
- range zone