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Scientists studying fossils in an ancient lake bed have an almost perfect fossil record ranging more than 5,000 years - VCE - SSCE Biology - Question 10 - 2015 - Paper 1
Question 10
Scientists studying fossils in an ancient lake bed have an almost perfect fossil record ranging more than 5,000 years. In this fossil record, there are two forms of ... show full transcript
Worked Solution & Example Answer:Scientists studying fossils in an ancient lake bed have an almost perfect fossil record ranging more than 5,000 years - VCE - SSCE Biology - Question 10 - 2015 - Paper 1
Step 1
Describe how the characteristics of fish in the lowest layer of the lake differ from those in the upper layer.
Answer
The fish in the lowest layer, having small pelvices and dorsal spines, show characteristics similar to those found in freshwater fish today. In contrast, the fish in the upper sediment layer have larger pelvic structures and may not possess dorsal spines, suggesting a shift towards marine adaptations.
Step 2
Explain why the fish with smaller pelvices and no spines might have a reproductive advantage.
Answer
The fish with smaller pelvices and no spines grow more quickly, which allows them to evade predation more effectively as young fish. Their faster growth rate means they can reach maturity sooner and thus have more opportunities to reproduce, contributing to the continuation of their genetic traits.