Question 22N.2.HL.TZ0.1e
| Date | November 2022 | Marks available | [Maximum mark: 2] | Reference code | 22N.2.HL.TZ0.1e |
| Level | HL | Paper | 2 | Time zone | TZ0 |
| Command term | Compare and contrast | Question number | e | Adapted from | N/A |
Common shrews (Sorex araneus) are small mammals found in Northern Europe. Their diet includes insects, slugs, spiders, worms and amphibians. They do not hibernate in winter because their bodies are too small to store sufficient fat reserves.
[Source: [Shrew], n.d. [image online] Available at: https://www.pxfuel.com/en/free-photo-jslkw [Accessed 29 October 2021].]
To study brain size in shrews, researchers anesthetize them, X-ray their skulls and measure the height of the braincase (BCH) where the brain is located. The graph shows the relationship between BCH and the brain mass of individual adult shrews.
[Source: adapted from Lá zaro, J., Hertel, M., LaPoint, S., Wikelski, M., Stiehler, M. and Dechmann, D.K.N., 2018.
Journal of Experimental Biology 221. http://doi.org/10.1242/jeb.166595.]
The researchers found that the BCH of any individual adult shrew could vary seasonally. They collected shrews at different times of the year. The BCH of each shrew was compared with its body mass. The results are displayed in the chart.
[Source: adapted from Schaeffer, P.J., O’Mara, M.T., Breiholz, J., Keicher, L., Lázaro, J., Muturi, M.,
Dechmann, D.K.N., 2020. R. Soc. Open Sci. 7. http://dx.doi.org/10.1098/rsos.191989.]
Compare and contrast the results for winter and spring.
[2]
Compare part of answer = similarity:
- both have low BCH (compared with summer);
Contrast part of answer:
- greater body mass in spring than winter;
OR
overall/mean/average BCH higher in spring than in winter;
OR
more variation in body mass in spring than winter;
For the second alternative in mpb, the answer must not state simply that BCH is higher in spring as there is much overlap. Do not accept quoted figures without the similarity or difference being stated.
This was a 'compare and contrast' question, so similarities and differences were expected in the answer. There were plenty of choices for differences between winter and spring but only one acceptable similarity — that BCH was lower in both winter and spring than in summer. Some answers failed to discriminate between BCH and brain mass — the trends were not the same so these terms were not interchangeable. Some candidates gave a comparison and then repeated it as the converse statement — for example 'sample mass is higher in spring than winter and is lower in winter than spring'. Clearly this is not necessary.
