BRAINCAKEBiotic Factors
Biotic factors are the living parts of an ecosystem that affect other organisms. They include:
• Competition: organisms compete for resources that are in limited supply, such as food, water, light, space, nesting sites and mates. Intraspecific competition is between members of the same species; interspecific competition is between different species.
• Predation: predators kill and eat prey. Predator and prey populations affect each other and often rise and fall in linked cycles.
• Parasitism and disease: parasites and pathogens harm their hosts and can reduce population size.
• Food availability: the number of plants or prey present limits the number of consumers that can be supported.
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Key terms in this lesson
- population
- All the individuals of one species living in the same area at the same time.
- carrying capacity
- The maximum population size that an environment can sustain over a long period of time, limited by the availability of resources.
- population density
- The number of individuals of a species per unit area.
More in Ecosystems
- Ecosystems
- Abiotic Factors
- Producers and Consumers
- Trophic Levels
- Biomass Transfer
- Ecological Efficiency
- Calculating Efficiency of Biomass Transfer
- Human Activities and Biomass Transfer
All 21 lessons in Ecosystems · All OCR A-level Biology topics