Question

VISUAL SKILLS The relative lengths of the frog and mouse

branches in the phylogenetic tree in Figure 26.13 indicate that

(A) frogs evolved before mice.

(B) mice evolved before frogs.

(C) the homolog has evolved more rapidly in mice.

(D) the homolog has evolved more slowly in mice.

Short answer

(A) The statement “frogs evolved before mice” is false.

(B) The statement “mice evolved before frogs” is false.

(C) The statement that “the homolog has evolved more rapidly in mice” is false.

(D) The statement that “the homolog has evolved more slowly in mice” is true.

Step-by-step solution

Phylogenetic Tree

The tree that shows characteristics of different species that evolved from the same ancestor is called a phylogenetic tree. This tree form branches into three main groups, which are bacteria, archaea, and Eukarya.

Explanation of option (A)

The frog is an organism that consists of the scientific name Anura and belongs to class amphibians. Mice is the lowest branch of the polygenetic tree that suggests that frogs cannot evolve from them.

Thus, the given phylogenetic tree cannot indicate that frogs evolved from mice.

Therefore, the given statement is false.

Explanation of option (B)

Mice are the organisms that belong to the kingdom Animalia. The information given in the phylogenetic tree indicates that frogs evolved before mice. Some of the characteristics of mice include possessing rounded ears and a high breeding rate.

Thus, mice cannot evolve before frogs in the given phylogenetic tree.

Therefore, the given statement is false.

Explanation of option ‘(C)’

The term homolog indicates organisms with similar structures to each other. Mice possess the lowest branch in the phylogenetic tree, which indicates that in mice, homolog evolved slowly, not rapidly.

Thus, homologs have not evolved rapidly in mice.

Therefore, the given statement is false.

Explanation of option (D)

The length in the phylogenetic tree indicates genetic change. The more extended branch indicates more genetic changes that occur slowly, and the smaller branch indicates few genetic changes that occur rapidly.

Thus, mice possess a longer branch length, which indicates they possess more genetic changes and homolog evolved more slowly.

Therefore, the given statement is true.