Question 21M.2.SL.TZ1.5c
| Date | May 2021 | Marks available | [Maximum mark: 1] | Reference code | 21M.2.SL.TZ1.5c |
| Level | SL | Paper | 2 | Time zone | TZ1 |
| Command term | Draw | Question number | c | Adapted from | N/A |
The image shows the wings of an insect, bird and bat.
[Source: [insect wing] Halvard Hatlen https://upload.wikimedia.org/wikipedia/commons/0/0f/Dip-trichoceridae-wing.png. [bird wing] University of Maryland, Department of Geology. [bat wing] University of Maryland, Department of Geology.]
Cladistics and other evolutionary evidence suggest that mammals and birds have a more recent common ancestor than mammals and amphibians. Draw a cladogram to show the relationships between mammals, birds and amphibians.
[1]
What is important is that the proper relationships are shown not the style used.
Candidates found it hard to express themselves without contradiction.
Examiners accepted a wide variety of diagrams and orientations as long as the relationships among amphibians, birds and mammals were appropriate. Nevertheless, there was poor performance on this question. It was the question most often left blank in Section A.
