Based on the phylogeny shown, choose the true statements about evolutionary relationships (Select all that apply).

Question

_____  A snake is more closely related to a newt than to a mouse.

_____  A newt is equally related to a snake and a chimp.

_____  A mouse is more closely related to a chimp than to a snake.

_____  A salamander is more closely related to a mouse than to a chimp.



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

_____  A snake is more closely related to a newt than to a mouse.
__X__  A newt is equally related to a snake and a chimp.
__X__  A mouse is more closely related to a chimp than to a snake.
_____  A salamander is more closely related to a mouse than to a chimp.

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 take what you already know and apply it to this unfamiliar situation.
· What key words does the question contain and what do they mean?
        o A phylogeny is a diagram describing a hypothesis about evolutionary relationships.
 
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 (synapomorphies) 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. These new characters are typically labeled on the branch.
 
Consider Possibilities
· Consider the different answer options. Which can you rule out?
        o Is a snake more closely related to a newt than to a mouse? No. Snakes are within the same clade as mice.
        o Is a salamander more closely related to a mouse than to a chimp? No, because mice and chimps are both members of the same distantly related clade.
 
Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o Is a newt equally related to a snake and a chimp? Yes, because snakes and chimps are both members of the same clade.
        o Is a mouse more closely related to a chimp than to a snake? Yes, because mice and chimps are members of the same clade.
  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 true statements based on interpreting the phylogeny.
        o The question required you to take what you already know and apply it to this unfamiliar situation.
        o Did you recognize that looking at the nested clades of a phylogeny can help you to understand how closely related species are?