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A2.1.1—Conditions on early Earth

Early Earth combined an oxygen-poor atmosphere, liquid water, strong natural energy sources, mineral surfaces, and extraterrestrial inputs that could support prebiotic chemistry.

Syllabus
First assessment 2025
Objective
A2.1.1
Level
HL

Exam analysis

Chance of appearing1%of analysed past papers
Latest appearanceMay 2013
Most common paperPaper3
Typical marks2–3

Common command terms

  • State
  • Evaluate
  • Outline

Scoring notes

Common mistake
Treating one proposed environment as the proven location where life began.

Recent exam appearances

May 2013Paper3 ["HL"] · TZ1D1(c)[ 2 ]A2.1.1—Conditions on early Earth
May 2013Paper3 ["HL"] · TZ1D1(b)[ 3 ]A2.1.1—Conditions on early Earth
Practice this objective

Coverage 2013–2013 · Updated 15 Jul 2026

Concept essentials

  • Early Earth had little free oxygen and no protective ozone layer.
  • Natural energy sources could drive reactions among simple substances.
  • Evaporation cycles could concentrate reactants in shallow water.
  • Mineral surfaces and extraterrestrial material could contribute catalysts or organic compounds.
ConceptIB Biology HL