IB Biology SL 4.2.1 Ecosystem energy and nutrient flows Question Bank
Practise IB Biology SL 4.2.1 by explaining how energy and matter move through ecosystems.
- Syllabus
- First assessment 2025
- Course
- Biology SL
- Level
- SL
Exam points
- Define an ecosystem as biotic and abiotic components interacting.
- Distinguish energy transfer from nutrient cycling in an ecosystem.
C4.2.1—Ecosystems as open systems question 1
[Maximum number: 6]
Describe the movement of energy and nutrients in an ecosystem.
ecosystem is a community and its abiotic environment; solar energy collected by autotrophs/plants (via photosynthesis);
moves through trophic levels via food; only 5 to 20 % transferred from one trophic level to next / never 100 % efficient;
lost as metabolic heat/organic waste; energy flow can be illustrated by pyramid shape;
organisms absorb nutrients from food/environment; nutrients occur as complex organic matter in living organisms; after death, saprotrophic bacteria and fungi (decomposers) breakdown complex
organic matter; breakdown products are simpler substances; absorbed into plants for resynthesis into complex organic matter/recycled;
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