Energy losses & pyramids of energy
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Flip to reveal answersAbout what percentage of energy passes to the next trophic level?
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All 12 Flashcards — Energy losses & pyramids of energy
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Question
About what percentage of energy passes to the next trophic level?
Answer
About **10%** — the other ~90% is lost at each level.
Question
In what three main ways is energy lost between trophic levels?
Answer
As **heat from respiration**, in **faeces (undigested waste)**, and in **uneaten or dead material**.
Question
What is the single biggest energy loss between trophic levels?
Answer
**Heat from respiration** — it leaves the ecosystem and cannot be passed on as food.
Question
Define energy transfer efficiency.
Answer
The **percentage** of energy at one trophic level that is passed on to the next — usually about **10%**.
Question
What is a pyramid of energy?
Answer
A diagram in which each bar shows the **energy** at one trophic level; the bars **get smaller** up the levels because energy is lost at each step.
Question
Why do the bars of a pyramid of energy shrink going up?
Answer
Because each level holds **less energy** than the one below — only ~10% is passed on each step.
Question
Is energy in an ecosystem recycled?
Answer
**No** — energy flows **one way** (sunlight → producers → consumers) and is steadily **lost as heat**; only nutrients are recycled.
Question
Why do food chains rarely exceed four or five links?
Answer
After several transfers **too little energy remains** to support another trophic level.
Question
Where does energy enter most ecosystems?
Answer
As **sunlight**, trapped by producers through **photosynthesis**.
Question
Which part of an organism's energy CAN be passed to the next level?
Answer
Only the energy built into its **biomass (body)** — and only the part that is actually **eaten**.
Question
Why is beef less energy-efficient to produce than chicken or plants?
Answer
Energy is lost at each trophic level, so the **extra transfer** (and cattle's poorer feed conversion) wastes more energy.
Question
Why are top predators rare in an ecosystem?
Answer
There is **very little energy** left at the top trophic level, so it can only support **a small number** of them.
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Topic 3.9 hub
Transfers of energy and matter
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