Year 7 Science · Unit 1 · Lesson 12
Apply Worksheet
Learning Goals
True or false? Fix the false ones
Circle T or F. If a statement is false, correct it on the line.
1. A structural adaptation is a body feature; a behavioural one is an action.
Correct it:
2. Behaviours can be switched on and off within minutes; body features cannot.
Correct it:
3. A survey with no independent variable is not a real investigation.
Correct it:
4. A kangaroo licking its forearms to cool down is a structural adaptation.
Correct it:
1. What is a quadrat? Why must a survey’s sampling rule be decided before you start?
Sort it: Results or Discussion?
A Results statement is measured or observed. A Discussion statement explains. Write each statement in the correct box. The boxes do not hold the same number of items.
Results
Discussion
Plan a survey
Aim: to compare the plants on the sunny side and the shaded side of your school building. Plan the survey before you go outside.
Prediction
It must be possible for your survey to show it is wrong.
Sampling rule
Where exactly, the quadrat size, how you choose where it goes, and what you record.
Read the data
Scenario: skinks on a sandstone rock
On a clear summer day, a student watched one large sandstone rock in a patch of bush. Every two hours she measured the temperature of the rock’s surface and counted the skinks basking on it. Skinks that were not on the rock were sheltering in cracks and under leaf litter nearby.
| Time | 7 am | 9 am | 11 am | 1 pm | 3 pm | 5 pm |
|---|---|---|---|---|---|---|
| Rock surface temperature (°C) | 14 | 24 | 36 | 48 | 40 | 28 |
| Skinks basking on the rock | 0 | 5 | 3 | 0 | 1 | 4 |
Source: made-up sample results for this worksheet.
2. Calculate how much the rock’s surface temperature rose between 9 am and 1 pm.
Rise °C
3. Describe the pattern in the number of skinks basking through the day, using numbers from Table 1. Then explain how basking and sheltering help a skink, and why the data show this is a behavioural adaptation.
4. A student writes: “Tree ferns have big flat fronds, which proves they are better adapted than mallee eucalypts.” Explain what is wrong with this claim, and rewrite it correctly.
True or false
1. True. 2. True. 3. False: a survey is a valid kind of investigation; it is made valid by a sampling rule fixed before you start and a prediction that could turn out wrong. 4. False: licking is something the kangaroo does, so it is a behavioural adaptation.
Question 1
A square frame of a set size placed at set points to record everything inside it (1). Deciding the rule first means what you record does not depend on what catches your eye, so the sample is not biased toward big or interesting organisms (1). [2 marks]
Sort it: Results or Discussion?
Results: six of the ten quadrats contained moss; the ground on the open side was 34 °C at noon; three snails were found under the fallen log. Discussion: moss only on the shaded side, which fits its need to stay damp; thick, waxy leaves on the open side probably lose less water in the sun.
Plan a survey
Prediction that can fail, e.g. “Moss and ferns will be found in more quadrats on the shaded side than the sunny side” (1). Sampling rule fixed in advance, e.g. a 50 cm quadrat every 2 m along a 10 m tape on each side, starting at the corner, recording every plant rooted inside (1). [2 marks]
Question 2
48 − 24 = 24 °C. [1 mark]
Question 3
No skinks basked at 7 am (14 °C), the most basked at 9 am (5 skinks, 24 °C), none at 1 pm when the rock was hottest (48 °C), and more returned by 5 pm (4 skinks, 28 °C) (1). Basking on a warm rock heats the skink up after a cool night (1); leaving the rock and sheltering at midday stops it overheating on a rock that is too hot (1). It is behavioural because the skinks switch it on and off within hours as the rock temperature changes, which a body feature could not do (1). [4 marks]
Question 4
Marking guide: 1 an adaptation is only an advantage in the habitat it suits, so “better adapted” has no meaning without saying “to what”; 1 conditions of the gully (deep shade, wet, rarely hot); 1 conditions of the mallee (low rain, over 40 °C, intense sun); 1 fronds catch scarce light, while small thick vertical leaves cut heat and water loss; 1 swapped, the tree fern would lose too much water in the mallee and the eucalypt would be shaded out in the gully; 1 a corrected sentence. [6 marks]
Model answer: The claim ranks two plants, but neither is better adapted in general; each is suited to different conditions. In a wet gully, water is plentiful and light is scarce, so broad, thin, flat fronds catch as much light as possible. In the mallee, rain is low and summer days pass 40 °C, so small, thick, waxy, vertical leaves heat less and lose less water. Moved to the mallee, a tree fern would lose water through its thin fronds and die; moved to the gully, a mallee eucalypt would be shaded out. Corrected: “Tree ferns have broad, flat fronds that suit the deep shade of a wet gully, while mallee eucalypts have small, thick, vertical leaves that suit hot, dry scrub.”
Common error: explaining the feature without naming the habitat, e.g. “big fronds are good because they catch more light”.