IB Biology D4.2: Stability and change (first exams in 2025)

This lesson can be purchased as part of the IB Complete course bundle (first exams 2025) at a heavily discounted price, formed of 40 fully resourced lessons, end of topic exams and student checklists. It can be found here

This PowerPoint contains everything you need to teach the Theme/Unit D4.2: Stability and change in the new IB Biology specification.

YouTube video is a preview of the full resource (does not include all slides)

This Powerpoint consists of over 60 slides and contains the followings:

• All the information the IB have included in the new spec.
• Clear diagrams
• Student friendly content
• Summary videos
• Student research tasks
• Clearly identified HL and SL content
• Student checklist
• Summary

The following content is included:

D4.2.1: Define ‘ecosystem stability’, including some examples of stable ecosystems.
D4.2.2: Outline the factors that affect stability and explain tipping points, using deforestation of the Amazon rainforest as an example.
D4.2.3: Evaluate the use of models to investigate the effect of variables on ecosystem stability.
D4.2.4: Explain the role of keystone species in the stability of ecosystems.
D4.2.5: Evaluate the sustainability of resource harvesting from natural ecosystems.
D4.2.6: Outline the factors affecting the sustainability of agriculture.
D4.2.7: Explain eutrophication and its effects on ecosystems.
D4.2.8: Outline biomagnification of pollutants.
D4.2.9: Describe the effects of microplastic and macroplastic pollution of the oceans.
D4.2.10: Describe the strategies for restoration of natural processes in ecosystems by rewilding.
D4.2.11: Define ecological succession and outline the causes.
D4.2.12: Describe the changes during primary succession.
D4.2.13: Describe cyclical succession.
D4.2.14: Distinguish between climax communities and arrested succession.