Year 7 Science · Unit 1 · Lesson 14

Energy Flow Through an Ecosystem

Foundation Worksheet

Name

Date

Class

Learning Goals

Explain the 10% rule and where the other 90% of energy goes.
Describe the shape of an energy pyramid and why it always narrows upwards.
Explain why food chains rarely have more than 4–5 trophic levels.

Warm Up

Odd one out

Circle the item that does not belong in each group. Then explain why it doesn't fit in the answer column.

#	Group	Your answer (odd one + reason)
1	Heat loss Movement Waste Photosynthesis
2	10% rule Energy pyramid Trophic level Decomposition
3	Producer Primary consumer Secondary consumer Sunlight

Your Turn

Sort it!

Write each item from the pool into the correct category column below.

10% of energy intake 90% lost at each level chemical energy in organisms respiration waste heat biomass at each trophic level energy used for movement energy stored in grass width of each pyramid bar droppings and waste kJ at each trophic level

Energy transferred to next level

Energy lost (not passed on)

Energy in the pyramid level

Show What You Know

1. Starting with 10 000 kJ in grass, how much energy is left for a secondary consumer (the third trophic level)? Show your working.

Recall 2 marks

2. Name the three main places where energy is lost between trophic levels in a food chain.

Recall 2 marks

Wrap Up

In one sentence, what was the main idea of this lesson?