Question

The cladogram shown below describes the evolutionary relationship among several species, labeled A to F. The five dots represent derived characters.
A cladogram includes a line with 5 dots. From bottom to top, the dots are labeled Trait 1 to Trait 5. Branches from the line lead to tips labeled A to F. Labels C and D are at the ends of very short branches off a longer branch.


The cladogram supports which of these predictions about the genomes of the six species?


A. The genome of species E is equally similar to the genomes of species D and F.

B. The genome of species E is more similar to the genome of species F than to any of the other species.

C. The genomes of species C and D are nearly identical because neither species has a derived character.

D. The genomes of the six species share few, if any, DNA sequences.

Answer 1

(You will find the cladogram in the attaches files)

Answer:

C. The genomes of species C and D are nearly identical because neither species has a derived character.  

Explanation:

A Cladogram is a tree-type graph based on cladistic analysis. It represents the common ancestral relationships among the involved groups.

• The tree-type graph is a ramified diagram that represents the relationship between the involved taxa.
• The cladistic analysis follows the maximum parsimony criterium. Explains the character state from the point of view of the fewest changes through history. Explains evolution with the minimal amount of evolutive changes. It recognizes the monophyletic groups as natural groups. These groups are the clades, and their classification -sequencing- represents their phylogeny.

• The sequencing term refers to lists of groups according to their relation. One group is the brother-group of the following one.

So the cladogram represents the relationship between groups according to a derived character.

The derivated character is any trait that a group passes to the descendants. Through evolution, the characters change, and new changes are added. When referring to a derivate character, we mean that all the subsequent species in the cladogram carry the trait.

A cladogram provides an image of how new species keep characters that were inherited from older species.  

So, in the exposed example, the five dots represent derived characters, representing traits 1 to 5. Branches A to F, represent groups. (See the cladogram in the attached files). Group A inherited trait 1, group B probably still carries trait 1, but also trait 2. Groups C and D equally inherited trait 3. Group E inherited character 4, and finally, group F inherited character 5.

Groups C and D inherited trait 3 and probably also still have traits 1 and 2. So they are very similar to each other. At a certain point, they diverged, probably due to a new mutation that was not passed to the rest of the group.  

C. The genomes of species C and D are nearly identical because neither species has a derived character. Correct.