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IB Biology SL A3.1.5 Difficulties in Distinguishing Species Questions

Speciation is gradual as isolated populations diverge. Populations may still be theoretically able to interbreed but cannot meet, so the boundaries between species can be partly arbitrary.

Syllabus
First assessment 2025
Course
Biology SL
Level
SL

Exam points

  • Explain that speciation is gradual as isolated populations diverge.
  • Explain that populations may still be theoretically able to interbreed even though they cannot meet.
  • Relate gradual divergence and inability to meet to species boundaries that can be partly arbitrary.

IB Biology SL A3.1.5 Difficulties in Distinguishing Species Questions question 1

[Maximum number: 1]

The graph shows the song duration of birds from the genus Phylloscopus sampled from west to east throughout Northern Europe and Northern Asia.

What concept do these data illustrate?

A

Gradual divergence

B

Adaptive radiation

C

Interbreeding populations

D

Punctuated equilibrium

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