IB Biology HL A3.2.7 Analysing cladograms Question Bank
Practise IB Biology HL A3.2.7 by interpreting roots, nodes and branching order to explain ancestry, relatedness and cladogram limits.
- Syllabus
- First assessment 2025
- Course
- Biology HL
- Level
- HL
Practise IB Biology HL A3.2.7 by interpreting roots, nodes and branching order to explain ancestry, relatedness and cladogram limits.
The gut of a healthy human contains more than 1000 species of bacteria. Some of these species are shown in the cladogram.

Identify, with a reason, whether the cladogram shows species X is more closely related to M. Iuminyensis or to E. faecalis.
a. X is more closely related to M . luminyensis;
b. smaller number of nodes/closer node between two clades/ species
OR
more recent common ancestor (with M. luminyensis) / common ancestor between X and E. faecalis is more distant (than with M. luminyensis)
OR
X and E. faecalis belong to different clades / X and M. luminyensis belong to the same clade;
For b. OWTTE.
For b. accept 'branching point' for node.