Environmental Science / Unit 2: Ecosystems and Energy Flow
2.1 Biotic and Abiotic Factors
Notes
An ecosystem is a community of living things interacting with their nonliving environment.
- Biotic factors are living or once-living parts: plants, animals, fungi, bacteria.
- Abiotic factors are nonliving: sunlight, temperature, water, soil, pH, oxygen.
- A population is one species in an area; a community is all populations living together; an ecosystem is the community plus abiotic factors.
- A habitat is where an organism lives; a niche is its role and the conditions it needs.
- A limiting factor (such as water in a desert) restricts population size.
- Example: in a pond, fish and algae are biotic; water temperature, dissolved oxygen, and sunlight are abiotic.
Practice
Which list contains only abiotic factors?
Algae, fungi, bacteria, and deer are living, so they are biotic.
All of the different species living and interacting in a forest make up a:
A community includes all populations in an area.
What is the difference between a habitat and a niche?
Habitat is the address; niche is the occupation.
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