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B4.1.7—Biomes

Biomes group ecosystems with similar communities because similar climate and abiotic conditions produce comparable vegetation and adaptations worldwide across continents.

Syllabus
First assessment 2025
Objective
B4.1.7
Level
SL

Exam analysis

Chance of appearing2%of analysed past papers
Latest appearanceNovember 2015
Most common paperPaper3
Typical marks1–3

Common command terms

  • Outline
  • Distinguish
  • Identify
  • State

Scoring notes

Common mistake
Defining the biosphere instead of a biome, or failing to distinguish the two.

Recent exam appearances

November 2015Paper3 ["SL"] · TZ020(c)(ii)[ 2 ]B4.1.7—Biomes
November 2015Paper3 ["SL"] · TZ020(c)(i)[ 1 ]B4.1.7—Biomes
May 2013Paper3 ["SL"] · TZ1G2(a)[ 1 ]B4.1.7—Biomes
May 2011Paper3 ["SL"] · TZ2G3(a)[ 3 ]B4.1.7—Biomes

Coverage 2011–2015 · Updated 15 Jul 2026

Climate Narrows the Likely Terrestrial Biome

Long-term temperature and rainfall are the main predictors of terrestrial biomes. Seasonality and insolation refine the prediction because they change water availability, growing season and productivity.

Show simplified climograph and named biome examples so the learner can predict A Biome From Climate.

warm + wet year-round → tropical forest
warm + very dry → hot desert
cold + short growing season → tundra
seasonal/moderate rain → grassland or temperate forest, depending on water balance

Similar Climates Can Produce Similar Biomes

A biome is a group of ecosystems with similar abiotic conditions and broadly similar communities. It is defined by climate and dominant vegetation, not by a single species list or a political boundary.

Separated regions can experience the same selection pressures. Natural selection may therefore favour independently evolved features with similar functions—convergent evolution—so their communities can have similar forms even though the species differ.

Climate predicts the broad biome; soil, altitude, fire, grazing and local history can shift the ecosystem found at one site, so biome boundaries are gradual rather than perfectly sharp.

Summary: Predict Distribution from Environment and Adaptation

measure environment → locate tolerance limits and optimum → predict possible distribution → test abundance in the field → explain how adaptations change performance

microhabitat: local moisture, light and temperature
species range: interacting tolerance, adaptation and dispersal limits
biome: long-term climate filters whole communities; similar pressures can produce convergent forms

Biomes exam focus

[ 2 ]

State what a biome is.

Concept essentials

  • Biomes are groups of ecosystems with similar communities and abiotic conditions.
  • The biosphere includes all regions of Earth where life occurs.
  • Tundra is characterised by low temperatures and low precipitation.
  • Similar climates can produce similar vegetation in different regions.