Question

47. This cladogram shows the evolutionary relationships among some mammals

Answer 1

Complete question:

This cladogram shows the evolutionary relationships among some mammals based on  homologous structures.

(You will find the cladogram in the attached files)

Which statement is supported by this cladogram?

A Hippopotamuses are more closely related to cows than to javelinas.

B Toothed whales are more closely related to mouse deer than to hippopotamuses.

C Javelinas and pigs are more closely related than baleen whales and toothed whales.

D Cows and mouse deer are more closely related than javelinas and pigs.

Answer:

A Hippopotamuses are more closely related to cows than to javelinas.

Explanation:  

A cladogram is a branched diagram of characteristics shared by the organisms of a group, that represents the most probable evolutive history of the linage. Cladograms reflect the phylogenetic relationships among groups through phylogenetic trees.

In the phylogenetic tree, the taxonomic groups of interest are located in the extremes of the lines called branches. The ramification point, which is also called "node" or divergence point, represents the location of the most recent common ancestor.

The common ancestor position will determine how related are two species. If they have a recent common ancestor, they are closely related to each other. On the other hand, if the common ancestor is not recent and is located far away in the tree, then the two species will be less related to each other.  

A Hippopotamuses are more closely related to cows than to javelinas. TRUE. Hippopotamuses share a common more recent ancestor with cows than with javelinas. This means that the hyppopotamus is more related to cows than to javelinas. The arrows in the cladogram (attached file) show the positions of the common ancestor shared by Hippopotamuses and Cows, and the common ancestor shared by Hippopotamuses and Javelinas.  

B Toothed whales are more closely related to mouse deer than to hippopotamuses. FALSE. Tooth whales are more related to the hyppopotamus. Their common ancestor is more recent than the common ancestor between toothed whales and mouse deer. The arrows in the cladogram (attached file) show the positions of the common ancestors.

C Javelinas and pigs are more closely related than baleen whales and toothed whales. FALSE. They are equally related.  

D Cows and mouse deer are more closely related than javelinas and pigs.

FALSE. They are equally related.