Abiotic and Biotic Factors
What Are Abiotic and Biotic Factors?
Abiotic and biotic factors are environmental conditions that affect where and how organisms live.
💡 Key Concept: These factors influence an organism’s survival, growth, and reproduction.
Abiotic Factors (Non-Living)
Abiotic factors are physical or chemical features of the environment.
Abiotic Factor | Effect on Organisms |
Light intensity | Affects photosynthesis and plant growth |
Temperature | Affects enzyme activity and metabolism |
Moisture levels | Needed for plant growth and animal hydration |
Soil pH and mineral content | Affects plant health and distribution |
Carbon dioxide levels | Needed for photosynthesis in plants |
Oxygen levels | Needed for respiration in animals and aquatic life |
Wind intensity and direction | Can affect transpiration and seed dispersal |
Biotic Factors (Living)
Biotic factors are living organisms that influence other species.
Biotic Factor | Effect on Organisms |
Availability of food | More food = better survival and reproduction |
New predators | Can reduce populations or drive extinction |
New pathogens | Can cause disease and reduce survival |
Competition | Species compete for limited resources (light, food, space, etc.) |
💡 A change in any factor can upset the balance of an ecosystem, affecting the food web.
Example: Rabbits in a Field
· Abiotic factors:
✔ Low rainfall → fewer plants → less food
✔ Extreme temperatures → increased energy loss
· Biotic factors:
✔ More foxes → more predation
✔ Disease outbreak → reduced population
How Do These Factors Affect Ecosystems?
✔ If an abiotic factor changes (e.g. pollution, drought), it may reduce plant growth → less food for herbivores → affects carnivores.
✔ If a biotic factor changes (e.g. new predator), it may reduce prey species → affects predators further up the food chain.
Questions
- What is the difference between abiotic and biotic factors?
- Name three abiotic factors.
- Give one example of a biotic factor.
- How does food availability affect animal populations?
- Why might a new pathogen be harmful to a population?
Summary
- Abiotic factors are non-living (e.g. light, water, temperature).
- Biotic factors are living (e.g. predators, food, competition).
- Changes to these factors can impact entire ecosystems and food chains.
- Understanding these factors helps us explain the distribution and abundance of organisms.