Biology 5090/61 — October/November 2013

Cambridge O-Level · Alternative to Practical · worked solutions for every part, with the mark scheme

questions

marks

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Topics Experimental Contexts · Analysis, Conclusions and Evaluation · Observations and Measurements · Use of Techniques, Apparatus and Materials · Planning Experiments and Investigations

Q116MAnalysis, Conclusions and EvaluationExperimental ContextsPlanning Experiments and InvestigationsFree sample

Warm blooded animals need to maintain a constant internal body temperature.

In cold weather some of these animals crowd together in groups.

Some students used test-tubes containing hot water to represent animals in an investigation into the loss of heat from animals' bodies.

One test-tube, A, represented one animal on its own, as shown in Fig. 1.1.

Another test-tube, B, represented an animal surrounded by seven similar animals in a group, as shown in Fig. 1.2.

Test-tube C represented one of the outer animals in the group, as shown in Fig. 1.2.

Fig. 1.1

Fig. 1.2

All nine test-tubes were filled with water at $70\,^\circ\text{C}$ . The temperature of the water in test-tubes A, B and C was measured when the tubes were filled and then every two minutes for a total of ten minutes.

The results are shown in Table 1.1.

Table 1.1

time / minutes	temperature / $^\circ\text{C}$ tube A	temperature / $^\circ\text{C}$ tube B	temperature / $^\circ\text{C}$ tube C
0	70	69	68
2	64	69	66
4	54	68	65
6	48	68	64
8	44	67	62
10	37	67	60

(a)

(i)

On the grid below, plot the results for the three test-tubes A, B and C on the same axes.

grid 1

(ii)

Describe and compare the temperature changes in each of the three test-tubes.

(iii)

Suggest and explain two ways to improve this method to make the results more reliable.

improvement 1 = ______
explanation = ______
improvement 2 = ______
explanation = ______

(b)

(i)

State which test-tube represents the animal that finds it easiest to maintain a constant body temperature.

______

(ii)

Suggest how animals crowding together in a group can help them to maintain body temperature in cold weather.

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3 more questions

Q2Experimental Contexts · Observations and Measurements · Analysis, Conclusions and Evaluation9M
Q3Experimental Contexts · Observations and Measurements · Use of Techniques, Apparatus and Materials10M
Q4Experimental Contexts · Use of Techniques, Apparatus and Materials5M

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