A-LevelBiologyBiodiversity and conservation9700/51 · May/June 2017 · Q210 Marks
An investigation was carried out into the size of individuals in a species of ground beetle common in Europe. Five different sites, A to E, were sampled during the three warmest months of the year. Table 2.1 shows information about the temperature at these sites. Table 2.1 site A B C D E average yearly temperature/°C 10.6 9.0 15.3 16.5 22.4 lowest average temperature/°C -2.1 -1.3 8.1 1.5 16.1 highest average temperature/°C 23.6 21.5 23.4 28.5 29.6 • The population at each site was sampled a total of 10 times during the three month period. • The beetles were sampled at 20 different locations within each site, on the same day. • The length of each captured beetle was measured to the nearest mm as a measurement of body size. • The beetles were divided into two groups according to body size, large and small. • The results from the different locations in each site were added together. • The population size and the percentages of large and small beetles in the population were estimated.
- (a)(i)State two variables which have been standardised in this investigation. 1 ................................................................................................................................................................. 2 .................................................................................................................................................................[2]
- (a)(ii)Outline how the population size of the beetles can be estimated.[2]
- (b)(i)Complete Table 2.2 by filling in the missing values for sites B and C.[2]
- (b)(ii)State, with a reason, whether these results support the hypothesis: The body size of individuals in populations of ground beetles increases as the environmental temperature decreases.[1]
- (c)State two other conclusions that can be made about the effect of temperature on body size of the beetles. 1 2[2]
- (d)Predict one way in which climate change may influence the populations of these ground beetles.[1]
This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.
Mark scheme
Marking points from the official mark scheme (May/June 2017). The mark or mark type is shown in brackets.
- [2] max 2 of: 1. the number of times the populations were sampled ; 2. the number of locations within each site; 3. the time of year that the populations were sampled ; 4. the day on which samples were taken (was the same); 5. idea that (size always) measured, as length / to nearest mm/in mm; 6. (one / the same) species of beetle (counted);
- [2] 1. trap/collect/sample / capture / AW, beetles, mark and release; 2. re-trap beetles, and count / record the number of marked beetles, out of the total number recaptured ;
- [2] number of small beetles (for site C): 7739; percentage of large beetles (for site B): 55;
- [1] supports idea that as the, percentage / proportion, of large beetles is, less in higher temperatures / more in lower temperatures ;
- [2] max 2 of: 1. as temperature increases, proportion / percentage of, large beetles decreases ; ora 2. idea that (temperature) variations between A, B and C do not seem to affect size much as, percentage / proportion, of large beetles similar (60, 55, 58); 3. ref. to differences in annual (temperature) range related to, percentage / proportion of, large / small, beetles ; 4. ref. to average yearly temperature values or groups of values linked correctly to stated percentage or proportion of, large / small, beetles ; 5. ref. to lowest average temperature values or groups of values linked correctly to stated percentage or proportion of, large / small, beetles ; 6. ref. to highest average temperature values or groups of values linked correctly to stated percentage or proportion of, large/small, beetles ;
- [1] must state what the aspect of climate change is considered e.g. warmer/cooler/more_extreme/wetter/drier/windier/stormier, etc one example of at least one possible climatic change and effect on population number or beetle size ;
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