Food webs and energy transfer
Arrows in a food chain show the direction energy travels — from the eaten to the eater. Only about 10% of energy passes to the next level.
Part of your national curriculum
- Working scientifically: Ask questions and develop a line of enquiry based on observations of the real world
- Working scientifically: Interpret observations and data, including identifying patterns and using observations to draw conclusions
- Biology: material cycles and energy: Understand the reactants in, and products of, photosynthesis, and a word summary for photosynthesis
- Biology: interactions and interdependencies: Understand the interdependence of organisms in an ecosystem, including food webs and insect pollinated crops
- Biology: interactions and interdependencies: Understand how organisms affect, and are affected by, their environment, including the accumulation of toxic materials
Lesson overview
What you'll learn in this lesson
Construct and interpret food chains and webs
Key learning points
- • Producers, consumers, decomposers
- • Why chains are short
This lesson at a glance
- 25 minutes
- 15 parts to scroll through
- 3 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 15
Visual introductionPicture this
Food webs and energy transfer
Arrows in a food chain show the direction energy travels — from the eaten to the eater. Only about 10% of energy passes to the next level.
In a nutshell
Construct and interpret food chains and webs
Explore the idea
Part 2 of 15
Learn
Producers, consumers, decomposers
Producers capture light energy. Consumers get energy second hand. Decomposers return nutrients to the soil, keeping the whole system running.
Explore the idea
Part 3 of 15
Learn
Why chains are short
With roughly 90% of energy lost at each transfer as heat and movement, there is rarely enough left to support a fifth or sixth level.
Reset break
Part 4 of 15
Pause
That's sitting 1 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Explore the idea
Part 5 of 15
Worked example
Worked example — wolves in Yellowstone
Returning wolves reduced elk browsing, willow and aspen recovered, beaver numbers rose and riverbanks stabilised. One predator changed the structure of a whole ecosystem.
Quick check
Part 6 of 15
Quick check
Part 7 of 15
Reset break
Part 8 of 15
Pause
That's sitting 2 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Quick check
Part 9 of 15
Challenge round
Part 10 of 15
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Challenge round
Part 11 of 15
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
____ capture light energy.
____ get energy second hand.
Reset break
Part 12 of 15
Pause
That's sitting 3 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Challenge round
Part 13 of 15
Game · Recall cards
An arrow in a food chain points…
Card 1 of 4
Mastery quiz
Part 14 of 15
Marked quiz
End of lesson quiz: Food webs and energy transfer
4 questions, marked with the reasoning shown. No timer.
1. An arrow in a food chain points…
2. Roughly how much energy passes to the next trophic level?
3. Removing a top predator most likely…
4. A class records that plant height increases as light hours increase, then levels off. What does the levelling off suggest?
Lesson round-up
Part 15 of 15
Lesson round-up
Ready when you are
Quiz score
Not sat
Games
Not played
Points this lesson
0
Best run
0 in a row
Luna: 0 out of 3 on the practice checks. Only if you feel up to it — one more?
Ask LunaPart 1 of 15 · Watch & discover
How this is going
- Not looked at yet
Ask questions and develop a line of enquiry based on observations of the real world
- Not looked at yet
Interpret observations and data, including identifying patterns and using observations to draw conclusions
- Not looked at yet
Understand the reactants in, and products of, photosynthesis, and a word summary for photosynthesis
- Not looked at yet
Understand the interdependence of organisms in an ecosystem, including food webs and insect pollinated crops
- Not looked at yet
Understand how organisms affect, and are affected by, their environment, including the accumulation of toxic materials