Question 21M.1A.SL.TZ2.20
| Date | May 2021 | Marks available | [Maximum mark: 1] | Reference code | 21M.1A.SL.TZ2.20 |
| Level | SL | Paper | 1A | Time zone | TZ2 |
| Command term | Question number | 20 | Adapted from | N/A |
Which is an example of speciation?
A. Selective breeding to produce new varieties of the wheat Triticum aestivum with higher crop yield
B. Evolution of different courtship behaviours in separate populations of the cricket Gryllus rubens
C. Natural selection leading to an increase in the frequency of darker individuals of Biston betularia
D. Selective feeding by koalas (Phascolarctos cinereus) on Eucalyptus species
[1]
B
Some G2 forms pointed out that speciation is not part of the SL material and only occurs in HL. Although there may be some justification in the comments, it was assumed that candidates would deduce what was required from their study of Topic 5.1 (Evidence for evolution) — populations of a species can gradually diverge into separate species by evolution. The question performed well according to difficulty and discrimination statistics.
