The Three Domain System

Part of Classification · Section 2 of 11

Key FactsUnit: Inheritance & EvolutionGCSE

This key facts covers The Three Domain System within Classification for GCSE Biology. Classification systems, taxonomy, and evolutionary relationships It is section 2 of 11 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.

The Three Domain System

Carl Woese proposed classifying life into three domains based on DNA:

ARCHAEA
Ancient bacteria-like organisms
Extreme environments
BACTERIA
True bacteria
Prokaryotes
EUKARYOTA
All other life
Animals, plants, fungi, protists

Practice questions for Classification

What is the highest level in the Linnaean classification system?

  • A. Species
  • B. Kingdom
  • C. Phylum
  • D. Class
1 markfoundation

What is the purpose of classifying living things based on their DNA and genome characteristics?

2 marksstandard

Quick recall flashcards

How do you correctly write a binomial (scientific) name?
Genus name first with CAPITAL letter, species name second in lower case — e.g. Homo sapiens. Both words are italicised when typed or underlined when handwritten. Example: Felis catus (domestic cat), Panthera leo (lion).
What is biological classification?
The process of sorting organisms into groups based on shared characteristics and evolutionary relationships. Classification helps scientists name, study, and communicate about the huge variety of life on Earth.

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