IB ESS · 2021 to 2026
Unit 2: Ecology
147 past paper questions from 29 papers across 10 exam sessions. See what repeats, then practise the same skills with AI marking.
Starter set across the most-tested skills, with AI marking and model answers.
SL archive · 2021 to 2026
Unit 2: Ecology
Latest exam session: Specimen 2026
- questions
- 147
- questions
- papers
- 29
- papers
- exam sessions
- 10
- exam sessions
- micro-topics
- 19
Topics in Unit 2: Ecology
In syllabus order. The ring is the share of the marks each one carries.
2.1
Individuals, populations, communities and ecosystems
50% of marks225 of the 452 marks across the 31 ESS papers analysed (50%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 60 questions
- DueSustainability & Resilience
2.2
Energy and biomass in ecosystems
26% of marks119 of the 452 marks across the 31 ESS papers analysed (26%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 41 questions
- DueLaws of thermodynamics
- DueFood webs
2.3
Biogeochemical cycles
10% of marks43 of the 452 marks across the 31 ESS papers analysed (10%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 19 questions
- RisingNitrogen cycle
2.4
Climate and biomes
6% of marks26 of the 452 marks across the 31 ESS papers analysed (6%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 14 questions
2.5
Zonation, succession and change in ecosystems
9% of marks39 of the 452 marks across the 31 ESS papers analysed (9%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 13 questions
Exam pattern
How often each micro-topic has been examined, year by year. Each label is explained under the grid.
Does it repeat?
Top 4 of 19 micro-topics for the next sitting. Numbers are questions per year.
fewermore
| Micro-topic | 2021 | 2022 | 2023 | 2024 | 2025 | 2026 |
|---|---|---|---|---|---|---|
| 4 Identification of Organisms, 2021: 4 questions | 1 Identification of Organisms, 2022: 1 question | 4 Identification of Organisms, 2023: 4 questions | 2 Identification of Organisms, 2024: 2 questions | 4 Identification of Organisms, 2025: 4 questions | 1 Identification of Organisms, 2026: 1 question | |
2.4.1Biomes | 1Biomes, 2021: 1 question | 3Biomes, 2022: 3 questions | 2Biomes, 2023: 2 questions | 2Biomes, 2024: 2 questions | 6Biomes, 2025: 6 questions | ·Biomes, 2026: 0 questions |
| 2Producers and consumers, 2021: 2 questions | 1Producers and consumers, 2022: 1 question | 3Producers and consumers, 2023: 3 questions | 3Producers and consumers, 2024: 3 questions | 1Producers and consumers, 2025: 1 question | 1Producers and consumers, 2026: 1 question | |
| 2Population interactions, 2021: 2 questions | ·Population interactions, 2022: 0 questions | 3Population interactions, 2023: 3 questions | 4Population interactions, 2024: 4 questions | 2Population interactions, 2025: 2 questions | ·Population interactions, 2026: 0 questions |
4 more micro-topics with a free account
- DueSustainability & Resilience· last Nov 24 P2 TZ1
- Dueusually examined, but missing from the last two exam sessions
Free account · no card needed
See the full exam pattern
Every micro-topic in the heatmap and the complete watch list, free with an account.
You come straight back to this page with your set built.
- With a free account
- 3 generated sets of 10 past-paper questions, any scope
- One AI-marked practice set with step-by-step feedback
- The full exam pattern: every micro-topic and the watch list
Past paper generator
Generate ESS past paper questions
Choose what to revise and build a set in one click. Every question stays whole, so multi-part questions come as they appeared in the exam.
- 1Pick any unit, topic or micro-topic
- 2Generate whole exam questions from the archive
- 3Practise the same skills with AI marking
Questions on Unit 2: Ecology, by exam session
Which papers asked about Unit 2: Ecology, and which question numbers. Open a paper to see them highlighted.
Specimen 2026
4 questions across 1 paper
May 2025
10 questions across 6 papers
November 2024
8 questions across 4 papers
May 2024
14 questions across 4 papers
November 2023
10 questions across 3 papers
May 2023
9 questions across 3 papers
November 2022
6 questions across 2 papers
May 2022
5 questions across 2 papers
November 2021
5 questions across 2 papers
May 2021
9 questions across 2 papers
Every Unit 2: Ecology question, unlocked
Generate all 147 questions in this unit at once, practise every one with AI marking, and see how each mark is awarded.
- Every past-paper question in any unit, topic or micro-topic
- Generate sets of 20 or all questions, as often as you like
- Unlimited practice with AI marking and worked answers
- See how every mark is awarded for each question
- Predicted papers and crash courses built from the same data
Used by IB students preparing for Nov 2026, May 2027 and May 2028
From €6/mo. 14-day money-back guarantee. Cancel anytime.
Frequently asked questions
Short answers about this page.
Which ESS exam sessions are covered for Unit 2: Ecology?
10 exam sessions from 2021 to 2026, the latest Specimen 2026. Every Paper 1 and 2 in every timezone is read and classified in full, which gives 29 papers in this archive.
Which Unit 2: Ecology topic comes up most?
Identification of Organisms (2.1.2): in 48% of papers, last seen Spec 26 P2. Usually "explain / justify", worth about 5.1 marks in a paper that includes it.
Can I see the original question and mark scheme?
No. The wording belongs to the IB. You get the citation, the marks, the command term and the skill tested, plus our own matched practice questions with worked answers and AI marking.
What do "banker", "due" and "rising" mean?
Banker: examined in at least one sitting in four and still appearing. Due: regular before, but absent for the last two exam sessions. Rising: clearly more common in the last two years. Our classification of real papers, not an IB statistic.
What is free and what needs Pro?
Reading this page and the exam pattern is free. A free account generates three sets of ten questions and launches one practice set. Pro opens every question in any scope, sets of twenty or all, and unlimited practice.
Keep going
More ESS exam preparation
Every question, by paper
What each ESS paper tests across all its sittings: the marks by unit and the micro-topics it keeps coming back to.
Open the paper analysis
Predicted questions
The question types most likely in the next ESS sitting, built from this same archive.
See the predictions
Formula booklet, explained
Every formula you are given in the exam, with when to use it and the traps around it.
Open the booklet guide
All IB past papers
Every subject we have classified by topic, with the same exam-pattern analysis.
Browse subjects