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IB Biology SL A4.1.4 Homologous structures Question Bank

Practise IB Biology SL A4.1.4 by using homologous bone structures and pentadactyl limbs as evidence for common ancestry.

Syllabus
First assessment 2025
Course
Biology SL
Level
SL

Exam points

  • Identify homologous structures by shared origin even when their functions differ.
  • Use pentadactyl limb bones to explain common ancestry and divergent adaptation.

A4.1.4—Evidence from homologous structures question 1

[Maximum number: 2]

The Chinese pangolin (Manis pentadactyla) is a critically endangered species that has declined in numbers by 80 % since 2000 . It inhabits both forest and grassland, where it uses long, powerful claws to open ant and termite nests and ingests the insects using a long, sticky tongue.

Figure for Question A4.1.4—Evidence from homologous structures question 1 — IB Biology SL

Outline evidence for evolution from the limbs of mammals such as pangolins.

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