BRAINCAKEAbiotic Factors and Population Size
Abiotic factors are the non-living conditions of an ecosystem. When an abiotic factor is close to the optimum for a species, individuals survive and reproduce well, and the carrying capacity is high. When conditions move away from the optimum, fewer individuals survive and the population is smaller.
Temperature
Enzymes work fastest near their optimum temperature. In ectotherms, such as insects, and in plants, body temperature follows the environment, so low temperatures slow metabolism and growth, while high temperatures can denature enzymes. Endotherms, such as mammals, keep their body temperature constant, but in cold conditions they use more energy to stay warm, leaving less for growth and reproduction.
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Key terms in this lesson
- ectotherm
- An organism that relies mainly on external sources of heat to regulate its body temperature.
- endotherm
- An organism that can generate and retain heat metabolically to maintain a fairly constant core body temperature.
More in Populations in Ecosystems
- Populations and Communities
- Ecosystems
- Niches
- Carrying Capacity
- Biotic Factors and Population Size
- Intraspecific Competition
- Interspecific Competition
- Predator-Prey Relationships
All 20 lessons in Populations in Ecosystems · All AQA A-level Biology topics