Chapter 17, Problem 2STP

Summary Introduction

Introduction:

A cladogram is a branching diagram that represents the proposed evolutionary history (phylogeny) of a species or group. The branching of a cladogram indicates phylogeny. The groups used in cladogram are called clads. The closeness of clades in the cladogram indicates the number of characters shared.

Answer to Problem 2STP

Correct answer:

The correct answer is option (D) rodentians and lagomorphans.

Explanation of Solution

Explanation/justification for the correct answer :

Option (D) rodentians and lagomorphans. They share characteristics such as ever-growing incisors and a diastema (space) separating the incisors from the cheek teeth. So, they have more recent common ancestor. Thus, this is the correct answer.

The explanation for the incorrect answer :

Option (A) carnivorans and chiropterans. Carnivorans have claws in the digits but in chiropterans, fore limbs are modified into wings. Thus, this is an incorrect option.

Option (B) cetaceans and hyracoidean are not related clads. Thus, this is an incorrect answer.

Option (C) dermopterans and carnivorans. They do not have more recent common ancestor are Thus, this is an incorrect answer.