2.4.4—Biome categories
- Syllabus
- First assessment 2026
- Objective
- 2.4.4
- Level
- HL
Compare Major Biomes by Limits, Productivity and Diversity
Biomes are broad groups of comparable ecosystems. Major groups include freshwater, marine, forest, grassland, desert and tundra; each can be divided into more specific types such as tropical rainforest, temperate forest or boreal forest.
| Biome group or example | Characteristic limiting factors | Typical productivity and diversity |
|---|---|---|
| Tropical rainforest | Nutrient-poor soils or low light below the canopy | High productivity and very high diversity |
| Hot desert | Very low and unpredictable water availability | Low productivity and relatively low diversity |
| Tundra | Low temperature, short growing season and permafrost | Low productivity and low diversity |
| Grassland | Seasonal water, fire and grazing | Moderate productivity; diversity varies with rainfall and disturbance |
| Freshwater | Light, nutrients, oxygen, temperature and flow | Highly variable among lakes, rivers and wetlands |
| Marine | Light, nutrients, temperature and water movement | Low in much open ocean but high in some coastal and upwelling systems |
Use the limiting factor to explain the pattern: year-round heat and water support rapid plant growth in rainforest, lack of water suppresses growth in hot desert, and cold plus a short growing season limits tundra.
Compare biomes with the same chain: abiotic limit → primary productivity → habitat and resource availability → biodiversity.
These are broad tendencies, not fixed scores: local nutrients, disturbance, depth, flow and seasonality can change productivity and diversity within one biome group.