Question 22N.2.HL.TZ0.1b
| Date | November 2022 | Marks available | [Maximum mark: 1] | Reference code | 22N.2.HL.TZ0.1b |
| Level | HL | Paper | 2 | Time zone | TZ0 |
| Command term | Outline | Question number | b | 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.]
Outline how the shrew labelled P differs from the normal relationship between BCH and brain mass.
[1]
- high BCH but brain mass is low/lower than expected/lower than others with similar BCH;
- (fairly) low brain mass but BCH is high/higher than expected/higher than others with similar brain mass;
Almost all candidates understood what made P an outlier, but not all could express lucidly how it deviated from the trend.
