| Biome | Mean Annual Temperature | Annual Rainfall | Key Characteristics |
|---|---|---|---|
| Tropical Rainforest | 25–30 °C (no cold season) | >200 cm | Highest biodiversity; multi-layered canopy; epiphytes |
| Tropical Savanna | 24–29 °C | 50–130 cm (seasonal) | Grassland with scattered trees; distinct wet/dry seasons |
| Desert | Highly variable (−5 to 45 °C) | <25 cm | Extreme temperature fluctuation; xerophytes; CAM plants |
| Chaparral (Mediterranean) | 15–20 °C | 25–75 cm (winter rain) | Shrubby vegetation; fire-adapted; drought-resistant |
| Temperate Grassland | −10 to 30 °C | 25–75 cm | Fertile soils (mollisols); bison/prairie ecology; no trees |
| Temperate Deciduous Forest | −5 to 25 °C | 75–150 cm | Seasonal leaf-shedding; distinct four seasons; oak, maple |
| Boreal Forest (Taiga) | −10 to 15 °C | 40–100 cm | Coniferous trees (spruce, fir); long winters; permafrost edge |
| Tundra | −15 to 5 °C | <25 cm | Permafrost; low-growing plants; no trees; short summer |
NEET Key Pattern: Moving from equator to poles: Tropical RF → Savanna → Desert/Grassland → Deciduous Forest → Taiga → Tundra. Rainfall decreases and temperature range increases.
| Cue Column | Notes Column |
|---|---|
| What are abiotic factors? | Non-living physical and chemical components of the environment that govern organism distribution and abundance. |
| 4 most important | Temperature (most ecologically relevant — affects enzyme kinetics); Water (limits productivity in deserts); Light (photoperiod controls flowering, migration, reproduction); Soil (pH, minerals, grain size determine plant communities) |
| Why is temperature #1? | Affects ALL biochemical reactions via enzyme kinetics. rule: metabolic rate doubles for every 10°C rise. Determines species distribution limits. |
| 4 response strategies | Regulators — maintain homeostasis (mammals, birds); Conformers — internal conditions fluctuate with environment (fish, reptiles); Migrants — move to favourable habitat (migratory birds); Suspend — dormancy (hibernation/aestivation/diapause) |
| Hibernation vs. Aestivation vs. Diapause | Hibernation = winter cold; Aestivation = summer heat/drought; Diapause = developmental arrest (zooplankton, insects) triggered by specific cues |
| NEET traps | 1. Temperature vs. water as "most important" — answer is TEMPERATURE. 2. Confusing hibernation (winter) with aestivation (summer). |
Summary (bottom): Abiotic factors set the ecological "rules." Temperature dominates because it controls enzyme function across all life. Organisms respond using four strategies — regulation (most energy-costly), conformity (most common), migration, or dormancy.