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Australian Eucalyptus trees characteristically have two types of leaves, a juvenile (young) form and an adult form - VCE - SSCE Biology - Question 22 - 2008 - Paper 1
Question 22
Australian Eucalyptus trees characteristically have two types of leaves, a juvenile (young) form and an adult form. The juvenile leaves are held horizontally and are... show full transcript
Worked Solution & Example Answer:Australian Eucalyptus trees characteristically have two types of leaves, a juvenile (young) form and an adult form - VCE - SSCE Biology - Question 22 - 2008 - Paper 1
Step 1
A selection pressure which is likely to have had the greatest influence on the evolution of the juvenile leaf shape and position would be
Answer
The correct answer is A. competition for light.
Juvenile leaves are designed to capture more light as they are broad and horizontally oriented, which helps in maximizing light interception in dense environments. This adaptation is crucial for young trees that need sufficient light to grow and develop successfully. The structure of adult leaves, being narrow and vertical, allows them to reduce light capture as the tree matures, conserving water while still obtaining adequate light as it reaches higher into the canopy.