IB ESS HL 3.1.17 Mass Extinction and Speciation Question Bank
Relate extinction events to adaptive radiation and subsequent speciation.
- Syllabus
- First assessment 2026
- Course
- ESS HL
- Level
- HL
Exam points
- identify the biodiversity or evolutionary process
- apply the correct diversity, selection or conservation concept
- justify the conclusion with evidence and ecological reasoning
3.1.17 (HL)—Mass extinction and speciation question 1
[Maximum number: 7]
Explain how the movement of tectonic plates has influenced biodiversity and evolution.
a. plate tectonic movement may lead to divergence of continents/growth of mountain ranges/opening of oceans/formation of islands...;
b. ...which separates populations/species from each other/isolates gene pools...;
c. ...leading to divergent evolution/action of natural selection/genetic drift / accumulating different mutations over (geological) time...;
d. ...as they have to adapt to different habitats/climates/environmental pressures (in order for fitter species to survive)...
e. ...causing speciation (thus, increasing biodiversity);
f. ...or may shift population in harsher climatic/habitat conditions, causing their extinction (thus reducing biodiversity);
g. plate tectonic movement may lead to formation of land bridges / closing of oceans…;
h. ...which brings different populations/species in contact / opens novel migration routes...;
i. ...leading to interspecific competition / competitive niche exclusion...;
j. ...which might cause the extinction of less fit species (reducing biodiversity);
k. ...also leading to hybridization/interbreeding of related species / increased gene exchange/flow...;
I. ...which may either reduce genetic differences / lump related species (thus, reducing biodiversity);
m. ...or create a new species better adapted to intermediate/new habitat/ e.g. introgression in plants (thus, increasing biodiversity);
Note: Do NOT credit description of evolutionary process (mutations / natural selection / survival of fittest / fitter genes dominating a population / speciation) outside the context of plate tectonics movement.
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