Biomass transfer: account for losses
| English | 中文 | Pinyin |
|---|---|---|
| transfer efficiency/ˈtrænsfɜː ɪˈfɪʃənsi/ | 传递效率 | chuán dì xiào lǜ |
| egestion/ɪˈdʒestʃn/ | 排遗 | pái yí |
What would explain this observation?
- Eating 100 kg of material does not add 100 kg to an animal’s body. Some is not absorbed and some supports respiration and other processes.
- Start with a prediction. State the quantities or features you would compare, then decide what evidence could distinguish two explanations.
Build the model
- Producers transfer only about 1% of incident light energy through photosynthesis in the specification’s approximate account. Only about 10% of biomass transfers from one trophic level to the next. Actual efficiencies depend on the supplied data, so these figures are guides rather than universal exact constants.
- transfer efficiency 传递效率: The proportion transferred to the next level under the stated measure; egestion 排遗: Removal of material that was not absorbed from food.
Which is egestion rather than excretion?
Not all ingested material is absorbed; some is egested as faeces. Absorbed material can be lost as respiration products, including carbon dioxide and water, or in excretion such as water and urea. Much glucose is used in respiration rather than retained as growth. Biomass available to higher consumers consequently decreases, helping explain smaller supported populations in a stated chain.
Match each technical term to its precise meaning.
Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- Not all ingested material is absorbed; some is egested as faeces. Absorbed material can be lost as respiration products, including carbon dioxide and water, or in excretion such as water and urea. Much glucose is used in respiration rather than retained as growth. Biomass available to higher consumers consequently decreases, helping explain smaller supported populations in a stated chain.
- Calculate transfer efficiency as biomass at the next level divided by biomass at the previous level, multiplied by 100. Use comparable mass units and sampling areas. Distinguish egestion of unabsorbed food from excretion of metabolic waste. A biomass ratio alone does not predict exact organism numbers without their individual masses.
Which two habits make the investigation or model in this case more defensible?
Calculate transfer efficiency as biomass at the next level divided by biomass at the previous level, multiplied by 100. Use comparable mass units and sampling areas. Distinguish egestion of unabsorbed food from excretion of metabolic waste. A biomass ratio alone does not predict exact organism numbers without their individual masses.
Work from known quantities
- State the known values and their units. Choose the relation because its assumptions fit this case, then rearrange before substitution.
- Known: supplied producer biomass is 800 kg and primary-consumer biomass 96 kg. Transfer efficiency = 96/800×100 = 12%. Use 12%, not force the answer to 10%. The remaining amount has several possible routes and cannot all be assigned to one named loss without more data.
Producer biomass is 500 kg and next-level biomass 60 kg. Calculate transfer efficiency. Use the same sequence: known quantities → model → relation → substitution → unit and interpretation.
Producer biomass is 500 kg and next-level biomass 60 kg. Calculate transfer efficiency.
The result is 12 %. Known: supplied producer biomass is 800 kg and primary-consumer biomass 96 kg. Transfer efficiency = 96/800×100 = 12%. Use 12%, not force the answer to 10%. The remaining amount has several possible routes and cannot all be assigned to one named loss without more data.
Check the conclusion and its limits
- Respiration transfers energy and releases material; do not call energy a lost kilogram of biomass. Ingested and absorbed are different amounts. A second transfer compounds the reduction rather than adding the percentages from two levels.
- Return to the original observation. Explain what the result supports, which conditions it assumes, and one way to test a competing explanation.
Every measured biomass-transfer efficiency must equal exactly 10%. This claim is false: Respiration transfers energy and releases material; do not call energy a lost kilogram of biomass. Ingested and absorbed are different amounts. A second transfer compounds the reduction rather than adding the percentages from two levels.
Biomass transfer: account for losses: Not all ingested material is absorbed; some is egested as faeces. Absorbed material can be lost as respiration products, including carbon dioxide and water, or in excretion such as water and urea. Much glucose is used in respiration rather than retained as growth. Biomass available to higher consumers consequently decreases, helping explain smaller supported populations in a stated chain.
Every measured biomass-transfer efficiency must equal exactly 10%.
Respiration transfers energy and releases material; do not call energy a lost kilogram of biomass. Ingested and absorbed are different amounts. A second transfer compounds the reduction rather than adding the percentages from two levels.
The proportion transferred to the next level under the stated measure: write the technical term.
transfer efficiency means The proportion transferred to the next level under the stated measure.