IB Diploma Biology HL, topic D4
Ecosystems (Continuity and change)
How populations and ecosystems change over time. Natural selection changes the heritable traits of populations, ecosystems stay stable only while certain requirements are met, and human activity, including climate change, can push them past tipping points.
Revision notes
Worksheet
FlashcardsSubtopics
Work through them in order. Each one has notes, exam questions and flashcards, and a PDF of each.
- 1Natural selection Spec D4.1IB Biology natural selection: variation, overproduction, selection pressures, fitness, sexual selection, Endler's guppies and Hardy–Weinberg (HL).NotesQuestions 8Flashcards 20
- 2Stability and change Spec D4.2IB Biology ecosystem stability: tipping points, mesocosms, keystone species, sustainability, pollution, rewilding and succession (HL).NotesQuestions 8Flashcards 26
- 3Climate change Spec D4.3IB Biology climate change: CO₂ and methane, positive feedback, tipping points, polar ice, coral reefs, range shifts and phenology (HL).NotesQuestions 8Flashcards 21
Whole topic
When you have done the subtopics: test yourself on everything, or print the lot.