AQA · GCSE · Biology
Course version: 8461 · Version from Sept 2018
They use current classification data for living organisms and fossil data…
Full specification wording
Classification of living organisms: They use current classification data for living organisms and fossil data for extinct organisms.
When scientists build evolutionary trees, they combine two kinds of evidence.
Checked against the AQA 8461 specification (opens in a new tab) on .
- Point 9 of 9
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
When scientists build evolutionary trees, they combine two kinds of evidence. For living organisms they use current classification data, including observable features, DNA base sequences, protein amino acid sequences and biochemical similarities. For extinct organisms they use fossil data, such as the age, structure and anatomy of fossilised remains, and increasingly any preserved biomolecules. Fossils provide the only direct record of organisms that no longer exist, so they help place extinct species on branches of the tree. For example, fossil evidence can show when a group first appears in the record, while DNA comparisons among living species show how closely those species are related. Combining both sources gives a more complete picture of evolutionary relationships than either source alone.
What earns the marks
- Current classification data for living organisms include physical features, DNA sequences and biochemical evidence.
- Fossil data for extinct organisms include the age, structure and anatomy of preserved remains.
- Fossils provide direct evidence about organisms that are no longer alive, helping place them on evolutionary trees.
- Combining living-organism data with fossil data gives a fuller picture of evolutionary relationships.
- New fossil finds or new molecular data can change where a species is placed on a tree.
Common mistakes and how to put them right
Using only fossils for living organisms.
Put it right by stating that current classification data are used for living organisms.
Using only DNA for extinct organisms.
Put it right by explaining that fossil data are used because extinct organisms cannot usually be sequenced.
Treating fossil data as unimportant.
Put it right by describing how fossils show when groups existed and what they looked like.
Exam tips
- Separate your answer clearly into evidence for living organisms and evidence for extinct organisms.
- Name at least one type of current classification data, such as DNA base sequences.
- Explain why fossils are needed: they are the direct record of extinct organisms.
Try the lesson
The start of the Classification of living organisms: They use current classification data for living organisms and fossil data for extinct organisms. lesson, made from checked teaching notes for this specification point.
Have a go first
Which type of data is primarily used to place extinct organisms on evolutionary trees?
Listen
When scientists build evolutionary trees, they combine two kinds of evidence. For living organisms they use current classification data, including observable features, DNA base sequences, protein amino acid sequences and biochemical similarities. For extinct organisms they use fossil data, such as the age, structure and anatomy of fossilised remains, and increasingly any preserved biomolecules. Fossils provide the only direct record of organisms that no longer exist, so they help place extinct species on branches of the tree. For example, fossil evidence can show when a group first appears in the record, while DNA comparisons among living species show how closely those species are related. Combining both sources gives a more complete picture of evolutionary relationships than either source alone. A strong answer earns marks for these points. Current classification data for living organisms include physical features, DNA sequences and biochemical evidence. Fossil data for extinct organisms include the age, structure and anatomy of preserved remains. Fossils provide direct evidence about organisms that are no longer alive, helping place them on evolutionary trees. Combining living-organism data with fossil data gives a fuller picture of evolutionary relationships. A common slip: Using only fossils for living organisms. Instead, stating that current classification data are used for living organisms. Exam tip: Separate your answer clearly into evidence for living organisms and evidence for extinct organisms.
See it
Key words
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Current classification data
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Fossil data
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Fossil record
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Combining multiple evidence sources
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See every definition
- Current classification data
- Data used for living organisms, including observable features, DNA base sequences, protein amino acid sequences and biochemical similarities.
- Fossil data
- Data used for extinct organisms, such as the age, structure and anatomy of fossilised remains, and increasingly any preserved biomolecules.
- Fossil record
- The only direct record of organisms that no longer exist, helping to place extinct species on branches of the tree.
- Combining multiple evidence sources
- Using both current classification data and fossil data, which gives a more complete picture of evolutionary relationships than either source alone.
Label the diagram
Some boxes have lost their names. Pick the right name for each number.
1Box 1
2Box 2
3Box 3
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