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C4.2.6—Autotrophs as self-feeders

Autotrophs as self-feeders explains how energy flow, matter cycling, trophic transfer or carbon movement is represented, measured or limited within ecosystems.

Syllabus
First assessment 2025
Objective
C4.2.6
Level
SL

Exam analysis

Chance of appearing4%of analysed past papers
Latest appearanceNovember 2025
Most common paperPaper2
Typical marks1–2

Common command terms

  • Identify
  • Distinguish
  • State
  • Define

Scoring notes

Common mistake
Confusing detritivores that ingest material with saprotrophs that digest externally.

Recent exam appearances

November 2025Paper2 ["SL"] · TZ35(a)[ 1 ]C4.2.6—Autotrophs as self-feeders
May 2018Paper2 ["SL"] · TZ23(b)[ 2 ]C4.2.6—Autotrophs as self-feeders
November 2013Paper1 ["SL"] · TZ018[ 1 ]C4.2.6—Autotrophs as self-feeders
May 2013Paper2 ["SL"] · TZ13(a)[ 2 ]C4.2.6—Autotrophs as self-feeders
May 2011Paper1 ["SL"] · TZ229[ 1 ]C4.2.6—Autotrophs as self-feeders
Practice this objective

Coverage 2011–2025 · Updated 16 Jul 2026

Concept essentials

  • Autotrophs as self-feeders must be linked to the correct source, store, transfer or loss process.
  • The evidence for autotrophs as self-feeders depends on distinguishing energy flow from matter cycling.
  • Autotrophs as self-feeders is clearer when arrows, units and trophic positions match the biological process.
  • Data or diagrams for autotrophs as self-feeders need interpretation as ecosystem transfer evidence.
ConceptIB Biology SL