Environmental Science Ecosystems and Ecology 1 — Questions and Answers
Question 1: Which term describes all living organisms and their physical environment interacting as a system?
- Biome
- Ecosystem (Correct answer)
- Community
- Population
Correct answer: Ecosystem
An ecosystem includes both the biotic (living) and abiotic (non-living) components interacting together.
Question 2: What is the primary source of energy for most ecosystems on Earth?
- Wind
- Water
- Sunlight (Correct answer)
- Geothermal heat
Correct answer: Sunlight
Sunlight is captured by photosynthetic organisms and forms the foundation of most food webs.
Question 3: Which trophic level consists of organisms that convert solar energy into chemical energy?
- Primary consumers
- Secondary consumers
- Producers (Correct answer)
- Decomposers
Correct answer: Producers
Producers (plants, algae, cyanobacteria) fix solar energy via photosynthesis and form the base of the food chain.
Question 4: The process by which nitrogen-fixing bacteria convert atmospheric Nâ‚‚ into ammonia is called:
- Nitrification
- Denitrification
- Nitrogen fixation (Correct answer)
- Ammonification
Correct answer: Nitrogen fixation
Nitrogen fixation converts inert atmospheric nitrogen gas into biologically available ammonia (NH₃).
Question 5: Which ecological concept describes the variety of species in a given area?
- Biomass
- Biodiversity (Correct answer)
- Biotic potential
- Bioaccumulation
Correct answer: Biodiversity
Biodiversity refers to the variety and variability of life forms in a specific habitat or region.
Question 6: In a food chain, approximately what percentage of energy is transferred from one trophic level to the next?
- 1%
- 10% (Correct answer)
- 50%
- 90%
Correct answer: 10%
The 10% rule states that only about 10% of energy is passed to the next trophic level; the rest is lost as heat.
Environmental Science Ecosystems and Ecology 1
Which term describes all living organisms and their physical environment interacting as a system?