IB ESS · 2021 to 2026

2.1 Individuals, populations, communities and ecosystems

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SL archive · 2017 to 2026

2.1 Individuals, populations, communities and ecosystems

Latest exam session: May 2026

questions
questions
papers
papers
exam sessions
exam sessions
By year19micro-topics

Micro-topics in 2.1 Individuals, populations, communities and ecosystems

In syllabus order. The ring is the share of papers each appears in. 6 of them have no matching questions in this archive.

  • 0

    2.1.1

    The biosphere

    No question tagged to this topic in the 50 ESS papers analysed

    No matches in this archiveRevise it
  • 0

    2.1.2

    Organisms and species

    No question tagged to this topic in the 50 ESS papers analysed

    No matches in this archiveRevise it
  • 2

    2.1.3

    Classification

    1 question · in 2% of papers

    Less common

    last May 22 P1

  • 14

    2.1.4

    Identification of organisms

    7 questions · in 14% of papers

    Rising

    last May 26 P2 TZ3

  • 2

    2.1.5

    Populations

    1 question · in 2% of papers

    Less common

    last Nov 20 P1

  • 10

    2.1.6

    Distribution: abiotic and biotic factors

    6 questions · in 10% of papers

    Occasional

    last May 26 P2 TZ2

  • 12

    2.1.7

    Abiotic factors

    6 questions · in 12% of papers

    Occasional

    last May 26 P1 TZ2

  • 8

    2.1.8

    Niches

    5 questions · in 8% of papers

    Occasional

    last May 26 P2 TZ3

  • 24

    2.1.9

    Population interactions

    15 questions · in 24% of papers

    Regular

    last May 25 P2 TZ1

  • 10

    2.1.10

    Carrying capacity

    6 questions · in 10% of papers

    Fading

    last Nov 22 P2

  • 2

    2.1.11

    Density-dependent factors

    1 question · in 2% of papers

    Less common

    last May 19 P2

  • 2

    2.1.12

    Population growth curves

    1 question · in 2% of papers

    Less common

    last May 24 P2 TZ1

  • 4

    2.1.13

    Limits on human population growth

    2 questions · in 4% of papers

    Less common

    last May 25 P2 TZ2

  • 12

    2.1.14

    Human carrying capacity

    6 questions · in 12% of papers

    Due

    last Nov 24 P2 TZ2

  • 14

    2.1.15

    Sampling methods

    7 questions · in 14% of papers

    Occasional

    last May 26 P1 TZ1

  • 6

    2.1.16

    Random quadrat sampling

    3 questions · in 6% of papers

    Occasional

    last Nov 24 P1 TZ2

  • 18

    2.1.17

    Capture-mark-release-recapture

    10 questions · in 18% of papers

    Regular

    last May 26 P2 TZ3

  • 2

    2.1.18

    Community

    1 question · in 2% of papers

    Less common

    last May 25 P2 TZ2

  • 0

    2.1.19

    Habitat

    No question tagged to this topic in the 50 ESS papers analysed

    No matches in this archiveRevise it
  • 4

    2.1.20

    Ecosystems as open systems

    2 questions · in 4% of papers

    Less common

    last May 19 P1

  • 0

    2.1.21

    Sustainability as a natural property of ecosystems

    No question tagged to this topic in the 50 ESS papers analysed

    No matches in this archiveRevise it
  • 2

    2.1.22

    Human activity and tipping points

    1 question · in 2% of papers

    Less common

    last May 18 P2

  • 12

    2.1.23

    Keystone species

    9 questions · in 12% of papers

    Occasional

    last May 26 P2 TZ2

  • 0

    2.1.24

    Biosphere integrity

    No question tagged to this topic in the 50 ESS papers analysed

    No matches in this archiveRevise it
  • 0

    2.1.25

    Reversing biodiversity loss

    No question tagged to this topic in the 50 ESS papers analysed

    No matches in this archiveRevise it

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-topic2017201820192020202120222023202420252026
2.1.17Capture-mark-release-recapture
1Capture-mark-release-recapture, 2017: 1 question1Capture-mark-release-recapture, 2018: 1 question·Capture-mark-release-recapture, 2019: 0 questions·Capture-mark-release-recapture, 2020: 0 questions3Capture-mark-release-recapture, 2021: 3 questions·Capture-mark-release-recapture, 2022: 0 questions1Capture-mark-release-recapture, 2023: 1 question1Capture-mark-release-recapture, 2024: 1 question1Capture-mark-release-recapture, 2025: 1 question2Capture-mark-release-recapture, 2026: 2 questions
2.1.4Identification of organismsRising · last May 26 P2 TZ3
·Identification of organisms, 2017: 0 questions·Identification of organisms, 2018: 0 questions·Identification of organisms, 2019: 0 questions1Identification of organisms, 2020: 1 question1Identification of organisms, 2021: 1 question1Identification of organisms, 2022: 1 question1Identification of organisms, 2023: 1 question·Identification of organisms, 2024: 0 questions1Identification of organisms, 2025: 1 question2Identification of organisms, 2026: 2 questions
2.1.9Population interactions
3Population interactions, 2017: 3 questions1Population interactions, 2018: 1 question·Population interactions, 2019: 0 questions1Population interactions, 2020: 1 question1Population interactions, 2021: 1 question·Population interactions, 2022: 0 questions3Population interactions, 2023: 3 questions5Population interactions, 2024: 5 questions1Population interactions, 2025: 1 question·Population interactions, 2026: 0 questions
2.1.15Sampling methods
1Sampling methods, 2017: 1 question1Sampling methods, 2018: 1 question2Sampling methods, 2019: 2 questions·Sampling methods, 2020: 0 questions·Sampling methods, 2021: 0 questions·Sampling methods, 2022: 0 questions·Sampling methods, 2023: 0 questions1Sampling methods, 2024: 1 question·Sampling methods, 2025: 0 questions2Sampling methods, 2026: 2 questions

4 more micro-topics with a free account

  • DueHuman carrying capacity· last Nov 24 P2 TZ2
  • Risingappearing more often in the last two years than before
  • Dueusually examined, but missing from the last two exam sessions

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Questions on 2.1 Individuals, populations, communities and ecosystems, by exam session

Which papers asked about 2.1 Individuals, populations, communities and ecosystems, and which question numbers. Open a paper to see them highlighted.

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Frequently asked questions

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Which ESS exam sessions are covered for 2.1 Individuals, populations, communities and ecosystems?

18 exam sessions from 2017 to 2026, the latest May 2026. Every Paper 1 and 2 in every timezone is read and classified in full, which gives 38 papers in this archive.

Which 2.1 Individuals, populations, communities and ecosystems topic comes up most?

Capture-mark-release-recapture (2.1.17): in 18% of papers, last seen May 26 P2 TZ3. Usually "Describe", worth about 4.4 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.

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