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A proposed phylogeny for the seven genera is shown in the diagram below, along with the countries in which they are found - VCE - SSCE Biology - Question 19 - 2012 - Paper 1
Question 19
A proposed phylogeny for the seven genera is shown in the diagram below, along with the countries in which they are found. Key Numbers in brackets ( ) refer to the ... show full transcript
Worked Solution & Example Answer:A proposed phylogeny for the seven genera is shown in the diagram below, along with the countries in which they are found - VCE - SSCE Biology - Question 19 - 2012 - Paper 1
Step 1
A. DNA sequences in Eucalyptus would be more similar to those in Allosyncarpia than to those in Stockwellia.
Answer
This statement is reasonable because both Eucalyptus and Allosyncarpia are shown to be closer on the phylogenetic tree, indicating a more recent common ancestor. In contrast, Stockwellia is further away on the tree, suggesting greater evolutionary divergence.
Step 2
B. speciation in Eucalyptus was assisted by different selecting pressures.
Answer
This assertion is supported, as speciation often results from different environmental pressures leading to adaptation in various species. The diversity of species within Eucalyptus also suggests multiple selecting pressures that have influenced its evolution.
Step 3
C. the greater the number of species in a genus, the younger the genus.
Answer
This statement can be misleading. A high number of species might indicate a successful and well-diversified lineage; however, it does not directly correlate with the 'youth' of the genus. Evolutionary time scales are complex and cannot be simplified this way.
Step 4