Edexcel A Level Biology A (Salters-Nuffield)
Edexcel A Level Biology A (Salters-Nuffield) Topic 5: Energy Transfer in Ecosystems Exam Questions
Free Edexcel A Level Biology A (Salters-Nuffield) exam questions on Topic 5: Energy Transfer in Ecosystems, with mark schemes. Covers gross and net primary productivity, energy transfer between trophic levels and ecosystem structure.
Topic 5: Energy Transfer in Ecosystems exam questions
These packs of real past exam questions cover the whole of Topic 5: On the Wild Side, including Topic 5: Energy Transfer in Ecosystems. Work through every question on this sub-topic, then mark your answers against the mark scheme.
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Edexcel A Level Biology A (SNAB) 9BN0 Flashcards (Anki & Quizlet)
Every answer is written in mark scheme wording, so you learn exactly what examiners give marks for. Use them on Anki or Quizlet, then test yourself with the questions on this page.
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About Edexcel A Level Biology A (Salters-Nuffield) Topic 5: Energy Transfer in Ecosystems
This part of Topic 5 covers how energy flows through ecosystems. Expect productivity calculations.
What you need to know
- Productivity GPP is the rate plants convert light energy into chemical energy; NPP = GPP minus respiratory losses.
- Energy transfer Energy is lost between trophic levels through respiration, heat, excretion and uneaten parts.
- Efficiency Efficiency = energy transferred to the next level / energy at the previous level x 100.
- Ecosystems Habitats, populations, communities and niches.
Common mistakes in Topic 5: Energy Transfer in Ecosystems
- Confusing GPP and NPP.
- Saying energy is recycled through an ecosystem.
- Forgetting to express efficiency as a percentage.
Try three Topic 5: Energy Transfer in Ecosystems exam-style questions
1. GPP is 20,000 kJ m⁻² yr⁻¹ and respiratory losses are 12,000. Calculate NPP. (1 mark)
Show the mark scheme answer
NPP = 20,000 - 12,000 = 8,000 kJ m⁻² yr⁻¹.
2. Explain why food chains rarely have more than five trophic levels. (2 marks)
Show the mark scheme answer
Energy is lost at each level through respiration and heat (1), so too little energy remains to support further levels (1).
3. Define net primary productivity. (2 marks)
Show the mark scheme answer
The energy stored in plant biomass (1) after respiratory losses are subtracted from GPP (1).
Topic 5: Energy Transfer in Ecosystems FAQs
What does this part of SNAB Topic 5 cover?
Productivity, energy transfer between trophic levels and the structure of ecosystems.
Do I need efficiency calculations?
Yes, as percentages from energy data.
Is energy recycled?
No. Energy flows through ecosystems and is lost as heat; nutrients are recycled.
Revise this topic with flashcards: Edexcel A Level Biology A (SNAB) 9BN0 Flashcards, with mark scheme answers for Anki and Quizlet.
