Choose the true statement about the morphological data in the chart shown below. The "1" in the box means the trait is present and the "0" indicates that the trait is absent.(Note: All of the characteristics across the top of the columns are considered "TRAITS" for purposes of reading the chart.).

Question

A.  All organisms in this chart share all of the derived characteristics.

B.  Only the gorilla and humans share all of the derived characteristics.

C.  The lamprey is the only outgroup since it has none of the derived characteristics.

D.  The salamander and the tiger together are the outgroup because they only share two of the derived characteristics (jaws and lungs).

E.  The shark is the outgroup since it only has one of the derived characteristics (jaws).





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 outgroups and derived characters?

 

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

C.  The lamprey is the only outgroup since it has none of the derived characteristics.

Clarify Question
· What is the key concept addressed by the question?
        o This question addresses outgroups and derived characters.
· 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 Morphological data refers to features of the anatomy.
 
Gather Content
· What do you already know about outgroups and derived characters?
        o The method of outgroup comparison is used to assign character polarity. To use this method, a species related to, but not a member of, the group under study is designated as the outgroup.
        o When a group has multiple character states, and one of those states is seen in the outgroup, that state is considered to be ancestral and other states are derived.
 
Consider Possibilities
· Consider the different answer options. Which can you rule out?
        o Is it true that all organisms in this chart share all of the derived characteristics? No. There are six derived characters, and each species does not posses each derived character.
        o Is it true that only the gorilla and humans share all of the derived characteristics? No, because in the chart humans have a derived character that gorillas lack – bipedalism.
        o Is it true that the salamander and the tiger together are the outgroup because they only share two of the derived characteristics (jaws and lungs)? No. The only outgroup here to all the other organisms is the lamprey, which lacks the derived characters.
        o Is it true that the shark is the outgroup since it only has one of the derived characteristics (jaws)?  No. The only outgroup here to all the other organisms is the lamprey, which lacks the derived characters.
  Choose Answer
  · Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o Is it true that the lamprey is the only outgroup since it shares none of the derived characteristics? Yes. The lamprey is the outgroup to the other organisms.
 
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 statement describing the species in the table.
        o The question required you to take what you already know and apply it to this unfamiliar situation.
        o Did you recognize that the lamprey is the outgroup, because it lacked the derived characteristics?