Energy transfer: use production and a stated boundary
הוצג| English | משמעות |
|---|---|
| trophic transfer efficiency/ˈtrəʊfɪk ˈtrænsfɜː ɪˈfɪʃənsi/ | יעילות העברת רמות תזונתיות |
| assimilation/əˌsɪmɪˈleɪʃn/ | היסחמה |
What would explain this observation?
- Energy available as new biomass usually decreases along a food chain. Energy is conserved overall, but some transferred energy leaves the next-level production pathway.
Build the model
- Producers convert an energy input into chemical energy in organic material.
- Consumers obtain material by feeding.
- Trophic transfer efficiency 营养级传递效率 compares production available at one level with production at the preceding level over a common area and time.
- Energy can enter detrital pathways, remain in uneaten material, leave in egested waste or be transferred as heat through respiration.
- trophic transfer efficiency: Production at one trophic level divided by production at the preceding level over a common interval.
- assimilation 同化: Uptake of digested material into an organism’s usable internal pool.
Which pair can be used for the stated transfer-efficiency calculation?
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
Transfer efficiency is a ratio of productions, so both values must be production in the same area, time and energy units. Mixing counts, standing biomass or unmatched units produces a meaningless number.
Match each technical term to its precise meaning.
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- Use the same energy units and period in numerator and denominator.
- Distinguish ingestion, assimilation and production: consumed energy is not all assimilated, and assimilated energy is not all stored as new biomass.
- An energy pyramid records a flow per area per time; a standing biomass snapshot is a different quantity.
In the lab: Analyse attributed or fictional ecosystem budget data. Draw a boundary and arrows for feeding, detritus and heat transfer. Identify which values are measured and which inferred, and check whether the budget includes decomposers. Avoid treating a fixed 10% rule as a universal measurement for every ecosystem.
Which two habits make the investigation or model in this case more defensible?
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
Stating the conditions and assumptions lets others repeat the work exactly, and recording the supporting evidence lets them check the conclusion. Hiding disagreeing results removes the evidence that could challenge a wrong conclusion, and one measurement can never establish a wider claim.
Work from known quantities
- Known: producer production is 10,000 kJ/m²/year and primary-consumer production is 1,200 kJ/m²/year.
- Transfer efficiency is 1,200/10,000×100=12%.
- Secondary-consumer production of 180 kJ/m²/year gives 180/1,200×100=15% for that step.
- These different values show why a universal 10% assumption would misrepresent this dataset.
Your turn: Producer production is 8,000 and primary-consumer production is 800 kJ/m²/year. Calculate transfer efficiency.
Producer production is 8,000 and primary-consumer production is 800 kJ/m²/year. Calculate transfer efficiency.
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
The result is 10 %. Known: producer production 8,000; primary-consumer production 800 kJ per square metre per year. Use efficiency = consumer production / producer production x 100. Efficiency = 800/8,000 x 100 = 10%. Other steps in the same system can differ, as the worked case shows.
Check the conclusion and its limits
- Energy is not destroyed when respiration transfers it as heat.
- Material can cycle through an ecosystem, while usable energy flow depends on continuing input.
- A count pyramid or biomass snapshot cannot automatically be substituted into an energy-efficiency calculation.
Not true: Respiration destroys energy instead of transferring it to other forms. Respiration transfers energy to the surroundings as heat - the energy still exists. "Loss" between trophic levels means energy leaves the food chain's usable flow; conservation is never violated.
- Producers convert an energy input into chemical energy in organic material.
- Use the same energy units and period in numerator and denominator.
- Watch for: energy is not destroyed when respiration transfers it as heat.
Write from a transfer efficiency of 30 percent
- Producer production is 8000 kJ per square metre per year. Primary-consumer production is 2400 in the same units.
- Find the transfer efficiency. Ingestion is not the same as production.
Respiration destroys energy instead of transferring it to other forms.
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
Respiration transfers energy to the surroundings as heat - the energy still exists. "Loss" between trophic levels means energy leaves the food chain's usable flow; conservation is never violated.
Production at one trophic level divided by production at the preceding level over a common interval: write the technical term.
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
trophic transfer efficiency means Production at one trophic level divided by production at the preceding level over a common interval.
Producer production is 8000 kJ per square metre per year and primary-consumer production is 2400 in the same units. What is the transfer efficiency, and why is energy eaten not the same as production?
2400 divided by 8000 is 0.30, which is 30 percent of producer production.
What is the transfer efficiency?
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
2400 divided by 8000 is 30 percent. Other options — 10 percent (the earlier calculation's result for 800 from 8000); 12 percent (the lesson example's result for 1200 from 10000).