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IB Biology HL A3.2.6 Constructing cladograms Question Bank

Practise IB Biology HL A3.2.6 by aligning sequences, applying parsimony and using molecular evidence or software to construct cladograms.

Syllabus
First assessment 2025
Course
Biology HL
Level
HL

Exam points

  • Align DNA or amino-acid sequences and use similarity, mutations and algorithms to build a cladogram.
  • Apply parsimony by choosing the tree requiring the fewest sequence or trait changes.
  • Use BLAST or alignment software to identify species and test phylogenetic relationships.

A3.2.6 (HL)—Constructing cladograms question 1

[Maximum number: 2]

International agreement limits the hunting of whales. Only the meat of the Minke, Fin and Humpback whales from Southern Hemisphere populations is allowed to be sold on the domestic market in Japan. Scientists obtained five samples of food that were being sold as "whale meat" in a Japanese market place. They identified the species and probable geographic origin of the meat using genetic analysis. The results were used to construct the cladogram.

Figure for Question A3.2.6 (HL)—Constructing cladograms question 1 — IB Biology HL

Explain how sequence alignment software might have been used in this study.

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