Chapter 15, Problem 2A

Summary Introduction

To replace:

The underlined words with correct words from the Study Guide.

Introduction: Darwin hypothesized that new species could appear gradually through changes in ancestral species but he could not understand how such a process could work. He consulted animal breeders- pigeon breeders in particular and found that a breeder can promote certain traits by selecting and breeding pigeons that have most prominent expression of traits.

Answer to Problem 2A

Artificial selection was used to produce purebred Chihuahuas and cocker spaniels.

Explanation of Solution

Different breeds of dogs have certain distinctive traits that are also present in that breed’s offspring. An animal breeder can promote these traits by selecting and breeding dogs that have most prominent expression of these traits. Breeding organisms with specific traits in order to produce offspring with identical traits is called artificial selection. This method was used toproduce purebred Chihuahuas and cocker spaniels.