IB Biology SL C4.2.22 Recycling of All Chemical Elements Questions
All chemical elements required by organisms are recycled in ecosystems. Decomposers convert detritus and waste into inorganic nutrients that producers can use.
Syllabus
First assessment 2025
Course
Biology SL
Level
SL
Exam points
Explain how decomposers and detritivores convert dead organic matter, detritus and waste into inorganic nutrients that producers can reuse.
Describe the recycling of elements such as carbon and nitrogen, and distinguish it from one-way energy flow.
IB Biology SL C4.2.22 Recycling of All Chemical Elements Questions question 1
[Maximum number: 2]
The bar chart shows the mass of animal feed required to produce one kilogram of meat, egg or milk (kg dry matter in feed per kg of output).
Feed conversion ratio / kg dry matter in feed per kg of output
Outline two ways in which agricultural production of animals may change the cycling of nutrients (for example phosphorus or nitrogen) in ecological systems.
a
animals remove nutrients from systems by feeding/being eaten;
b
nutrients added to systems by fertilizers/manure;
c
fertilizer/manure/organic matter run-off can affect other ecosystems;
d
deforestation results in leaching/loss of nutrients;