The table shows when fossils of three forms occur. Fossil recovery is incomplete, and all ages are reliable.
Table
| Form Oldest fossil / million years Youngest fossil / million years | :---: :---: :---: | P 18 8 | Q 12 4 | R 6 1 |
| ------------------------------------------------------------------------ | ----------------------- | ------------ | ------------ | ----------- |
P resembles Q, and Q resembles R. A student claims that all P became Q at 12 million years ago and all Q became R at 6 million years ago.
Which evaluation is correct?
The age ranges support complete replacement; resemblance alone cannot establish which form appeared first.
The age ranges rule out common ancestry; resemblance alone cannot establish when each form disappeared.
The age ranges establish direct ancestry; overlapping forms must belong to a single unchanged species.
The age ranges contradict complete replacement; resemblance alone cannot establish a direct ancestral sequence.
40 exam-style questions on AQA GCSE Biology 6.3 The development of understanding of genetics and evolution, covering 6.3.1 Theory of evolution, 6.3.2 Speciation, 6.3.3 The understanding of genetics, 6.3.4 Evidence for evolution, 6.3.5 Fossils, 6.3.6 Extinction, and 6.3.7 Resistant bacteria. Each one has a worked solution and a mark scheme showing where the marks go.