IB skill practice

Analyse molecular evolution and phylogenetics

Paper 1, Paper 2 5 marks Difficulty 5

Identify the most recent common ancestor

A phylogenetic tree in a chromosome modelling activity places species 1 and species 2 on sister branches joined by the nearest internal node. State what that node represents. Use the diagram labels, data values, or inheritance pattern before writing the answer. Enter the answer and choose the interpretation that best matches the HL Biology evidence.

Worked practice: biological evidence and answer

Use the labelled biological evidence first, then connect it to the final answer.