Based on the phylogeny shown, the group of species including (2-5) can best be described as a

Question

A.  clade.
B.  paraphyletic group.
C.  polyphyletic group.
D.  cladogram.
E.  synapomorphy


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 phylogenetic trees?
 
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.  clade.


Clarify Question
· What is the key concept addressed by the question?
        o This question addresses phylogeny.
· 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 an evolutionary tree which represents a hypothesis about patterns of relationship among species.

  Gather Content
· What do you already know about phylogenetic trees?
        o A phylogenetic tree is a way of diagramming a hypothesis about evolution.
        o The tips of the twigs represent existing species. As one works down the tree, the joining of twigs and branches reflects the pattern of common ancestry back in time to the single common ancestor of all life.
 
Consider Possibilities
· Consider the different answer options. Which can you rule out?
        o Can you describe species 2-5 as a paraphyletic group? No. A paraphyletic group is a group that includes the most recent common ancestor of the group, but not all its descendants.
        o Can you describe species 2-5 as a polyphyletic group? No. A polyphyletic group is a group that does not include the most recent common ancestor of all members of the group.
        o Can you describe species 2-5 as a cladogram? No. The diagram itself can be described as a cladogram, but not species 2-5.
        o Can you describe species 2-5 as a synapomorphy? No. A synapomorphy is a derived character shared by members of a clade – but a synapomorphy is not what we call the clade itself.

  Choose Answer · Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o Can you describe species 2-5 as a clade? Yes.
        o A monophyletic group includes the most recent common ancestor of the group and all of its descendants. By definition, a clade is a monophyletic group.
 
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 what term could best describe the species 2-5 in this phylogenetic tree?
        o The question required you to take what you already know and apply it to this unfamiliar situation.
        o Did you recognize that a clade is a group containing all descendants of a common ancestor?