Question

The following phylogeny shows how species P to T are related to each other. The branch lengths indicate the degree of evolutionary change. 

The species composition of three areas is given below: 
\(\text{Area 1: PQR; Area 2: RST; Area 3: QRS}\) 
Given this information, the phylogenetic diversity of 
 

• A. Area 1 \(>\) Area 3 \(>\) Area 2
• B. Area 1 = Area 2 = Area 3
• C. Area 1 = Area 3 \(>\) Area 2
• D. Area 1 \(<\) Area 3 \(<\) Area 2

Hint:

Phylogenetic diversity is higher when species in an area are more distantly related.

Answer 1

The Correct Option is A

The phylogenetic diversity of a region can be understood by examining the species composition and the degree of evolutionary change indicated by branch lengths in the phylogeny. In this case, we are given the species composition for three areas:
- Area 1 contains species PQR.
- Area 2 contains species RST.
- Area 3 contains species QRS.
Looking at the phylogeny:
- Area 1 has species P, Q, and R. The species P and Q are relatively closely related (as per the branch lengths), but R is more distantly related, implying a higher degree of phylogenetic diversity for this area.
- Area 3 has species Q, R, and S. This is similar in diversity to Area 1, but it lacks species P, making the diversity slightly lower than in Area 1.
- Area 2 has species R, S, and T. The species in this area appear to be relatively closely related, with less phylogenetic distance between them compared to Areas 1 and 3. Hence, Area 2 has the least phylogenetic diversity.
Therefore, the phylogenetic diversity follows the pattern: Area 1 > Area 3 > Area 2. The correct answer is (A).