The figures show alternative phylogenies of HIV strains in a victim who was infected with HIV+ blood and in potential sources of the blood (“Patient”) and HIV strains in members of the community (“Community”). Choose the true statement(s) about the evolution of this HIV strain (Select all that apply).

Question

_____  Figure 1 supports that the victim contracted HIV from the patient, and Figure 2 supports that the victim contracted HIV from someone in the community.  

_____  Figure 1 supports that the victim contracted HIV from someone in the community, and Figure 2 supports that the victim contracted HIV from the patient.



_____  Figure 1 supports that the HIV strain mutated into a new strain inside the victim’s body, and Figure 2 supports that HIV did not mutate into a new strain inside the victim’s body.

_____  Figure 1 supports that the HIV strain did not mutate into a new strain inside the victim’s body, and Figure 2 supports that HIV mutated into a new strain inside the victim’s body.





Clarify Question

· What is the key concept addressed by the question?

· What type of thinking is required?

· What key words does the question contain and what do they mean?

 

Gather Content

· What do you already know about cladistics?

 

Consider Possibilities

· Consider the different answer options. Which can you rule out?

 

Choose Answer · Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?

 

Reflect on Process

· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

__X__  Figure 1 supports that the victim contracted HIV from the patient, and Figure 2 supports that the victim contracted HIV from someone in the community.  
_____  Figure 1 supports that the victim contracted HIV from someone in the community, and Figure 2 supports that the victim contracted HIV from the patient.

__X__  Figure 1 supports that the HIV strain mutated into a new strain inside the victim’s body, and Figure 2 supports that HIV did not mutate into a new strain inside the victim’s body.
_____  Figure 1 supports that the HIV strain did not mutate into a new strain inside the victim’s body, and Figure 2 supports that HIV mutated into a new strain inside the victim’s body.

Clarify Question
· What is the key concept addressed by the question?
        o This question addresses cladistics.
· What type of thinking is required?
        o This question is asking you to analyze the information given, using logic, to dissect the problem and determine the answer.
· What key words does the question contain and what do they mean?
        o HIV strains are different versions of the Human Immunodeficiency Virus that may differ in specific nucleotides.
 
Gather Content
· What do you already know about cladistics?
        o Cladistics is the method used to construct a cladogram — a graphically represented hypothesis of evolutionary relationships.
        o Only shared derived characters are useful for inferring phylogenies, and they must be contrasted to an outgroup that has the ancestral characters.
        o Each nested clade is defined by a new shared derived character.
 
Consider Possibilities
· Consider the different answer options. Which can you rule out?
        o Does Figure 1 support that the victim contracted HIV from someone in the community, and Figure 2 support that the victim contracted HIV from the patient? No. The branching patterns suggests the opposite.
        o Does Figure 1 support that the HIV strain did not mutate into a new strain inside the victim’s body, and Figure 2 support that HIV mutated into a new strain inside the victim’s body? No, the two “Victim” strains are seen in Figure 1.
 
Choose Answer · Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o Does Figure 1 support that the victim contracted HIV from the patient, and Figure 2 support that the victim contracted HIV from someone in the community? Yes, because the branching pattern shows that those are most closely related.
        o Does Figure 1 support that the HIV strain mutated into a new strain inside the victim’s body, and Figure 2 support that HIV did not mutate into a new strain inside the victim’s body? Yes, because only in Figure 1 are there two closely related strains marked “Victim”.
 
Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        o This question asked you to choose the correct statements about two cladograms of HIV strains.
        o The question required you to analyze the information given, using logic, to dissect the problem and determine the answer.
        o Did you recognize that the branching pattern is crucial for understanding the relationships in a cladogram?