Two sites preserve rocks of the same age. At site P, rapid burial produced oxygen-poor mud. At site Q, remains stayed exposed in warm, oxygen-rich water before burial. Both sites later experienced similar geological disturbance.
P contains many soft-bodied fossils. Q contains mostly shells.
Which conclusion best accounts for both the conditions and the fossil evidence?
P necessarily had more soft-bodied species; similar later disturbance removes any difference in preservation probability.
Q necessarily had more shelled species; warm water preserves shells and soft tissue with equal probability.
P better preserved soft tissues; similar later disturbance does not remove the earlier difference in decay.
Q better preserved soft tissues; oxygen-rich water prevents decomposers from removing organisms before their burial.
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.