Insects That Changed to Survive

Science · Insects & Minibeasts · ages 9-11

Name ______________________ Date ____________

What is a stick insect's body shape an example of?
- A costume it puts on for fun
- An adaptation that helps it avoid being eaten
- A trick it learned by watching other insects
Why did peppered moths become mostly dark during the Industrial Revolution?
- Soot covered the trees, so dark moths were hidden and pale moths were easier for birds to spot
- Moths ate soot and it changed their colour
- Dark moths are naturally stronger than pale moths
An insect can change its own colour or shape during its lifetime because it needs to hide better.
Circle one: True False
Look at the bar chart. How many more pale moths were eaten than dark moths after soot covered the trees?
Answer: ______________
Before the Industrial Revolution, tree trunks in England were light and covered in pale lichen. Which peppered moths likely survived best then?
- Dark moths
- Both colours survived equally
- Pale, speckled moths
A newly hatched stick insect looks a little rounder than its twig-shaped parents. Over the next few years, will that one insect's body gradually turn twig-shaped to match?
- No, adaptation happens across generations, not within one insect's life
- Yes, it slowly reshapes itself as it grows
- Yes, but only if it eats enough leaves
Priya says: "Ant-mimicking spiders learned to look like ants by copying them, the same way a person learns a dance." What is wrong with Priya's explanation?
- Spiders looked like ants long before ants existed
- Nothing is wrong, spiders really do copy ants on purpose
- Spiders cannot choose their appearance; ant-like features spread because ant-like spiders survived and had babies over many generations
A stick insect species lives on a plant with reddish-brown twigs instead of green ones, so predators can see the green insects clearly. What would need to happen, over many generations, for the insects to become well hidden again?
- Every green insect would need to change colour by rubbing against the red twigs
- Insects with more reddish-brown colouring would need to survive and have babies more often than green ones
- The insects would need to move to a completely different plant

Answer key

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Insects That Changed to Survive W1-mt_7_XXh9NCp0-s1

An adaptation that helps it avoid being eaten · Its twig-like shape hides it from hungry predators, and that is an adaptation.
Soot covered the trees, so dark moths were hidden and pale moths were easier for birds to spot · Soot-covered trees hid dark moths from birds, so more dark moths survived and had babies.
False · Adaptations build up over many generations of a species, not inside one insect's life.
6 · 8 pale moths eaten minus 2 dark moths eaten leaves 6 more pale moths eaten.
Pale, speckled moths · Pale moths blended in with the light bark, so birds had a harder time spotting them.
No, adaptation happens across generations, not within one insect's life · That insect keeps its shape for life. Twig shapes spread through a population only as generations pass and better-hidden insects survive to have babies.
Spiders cannot choose their appearance; ant-like features spread because ant-like spiders survived and had babies over many generations · No spider decides to look like an ant. Over generations, spiders that happened to look more ant-like were less likely to be eaten, so that look spread.
Insects with more reddish-brown colouring would need to survive and have babies more often than green ones · Being hidden works the same way it did for the original stick insects: insects that already match their surroundings survive better and pass that colouring to their babies.