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IB Biology SL D4.3.6 Range Shifts Questions

Interpret northward or poleward range shifts and explain how warming changes competition, predation, survival and cod population genetics.

Syllabus
First assessment 2025
Course
Biology SL
Level
SL

Exam points

  • Interpret climate-induced poleward or northward range shifts using dolphin, predator, cod and hardiness-zone evidence.
  • Explain how warming-driven distribution shifts alter competition, predation, prey availability and local species survival.
  • Predict population or allele-frequency consequences when warming shifts a species’ range, using the cod case study.

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Study D4.3.6—Range shifts conceptsOpen the corresponding Concept lesson for explanations, examples and exam connections.

IB Biology SL D4.3.6 Range Shifts Questions question 1

[Maximum number: 2]

Bottlenose dolphins (Tursiops truncatus) inhabit almost all tropical and temperate oceans between 45∘N45^{\circ} \mathrm{N} and 45∘S45^{\circ} \mathrm{S}. Over a two-year period, aerial surveys were carried out to investigate the seasonal distribution of these animals along the mid-Atlantic and eastern coastal waters of the USA. Sightings were recorded using a global positioning system (GPS) while flying parallel to the coast approximately 500 m offshore. The diagram below shows a map of the section of coast surveyed. The bar graph shows the seasonal data for summer and winter at the corresponding latitudes ( ∘N{ }^{\circ} \mathrm{N} ). A total of 5431 bottlenose dolphins were sighted during these surveys.

Figure for Question IB Biology SL D4.3.6 Range Shifts Questions question 1 — IB Biology SL

Explain how an increase in water temperature due to global warming could affect the distribution of bottlenose dolphins along the eastern coast of the USA.

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