An evolutionary biologist used several methods to construct a phylogenetic tree for a group of mammals - VCE - SSCE Biology - Question 36 - 2023 - Paper 1

To determine which method would have been least useful in constructing a phylogenetic tree for mammals, we need to consider the relevance and amount of genetic or structural information provided by each method.

1. Amino Acid Sequences: These are quite useful, as they provide direct insights into the evolutionary relationships based on protein structures.

2. Protein Sequences: Similar to amino acid sequences, analyzing protein sequences can reveal evolutionary connections and provide valuable information for constructing a phylogenetic tree.

3. Bone Structure: This method relates more to morphological characteristics and could prove informative, but it may not provide as precise information as genetic sequences.

4. Presence of Hair: The presence or absence of hair is a trait that may vary widely among different mammals and does not give detailed genetic information, thus not very useful for constructing a phylogenetic tree.

Considering these points, the least useful method for constructing a phylogenetic tree would be D. presence of hair, as it does not provide sufficient evolutionary information in comparison to the other options.