Chapter 15, Problem 7A

Summary Introduction

To determine:

Similarities between artificial selection and natural selection

Introduction:

The process by which desired traits of certain plants and animals are selected and passed on to their future generations is called selective breeding. It is a conscious effort to select the desired traits and then develop new generations with the new traits. Charles Darwin gave a theory of natural selection. He argued that if enough time is given, natural selection could modify a population to produce new species.

Answer to Problem 7A

Charles Darwin found that artificial selection could change an ancestral species into a new species by selective breeding. He inferred that if humans could change species by artificial selection, then the same process could also work in nature. This led to the theory of natural selection which suggests that a population could get modified to produce new species by undergoing variation, inheritance, overproduction of offspring and reproductive success.

Hence, both artificial selection and natural selection can introduce new species into the environment by promoting favorable traits.

Explanation of Solution

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. The process of selective breeding is called artificial selection. In this way new species could be developed over time.

Charles Darwin in his theory of natural selection proposed that natural selection could modify a population to produce new species. There are four principles of this theory.

1. Individual in a population show differences called variations.
2. Variations can be inherited; i.e they can be passed down from parent to offspring.
3. Organisms produce more offspring than can survive on available resources.
4. Variations that increase reproductive success will have a greater chance of being passed on than those that do not increase reproductive success.

In this way new species can be introduced into nature. Both artificial selection and natural selection can introduce new species into the environment by promoting favorable traits. However one occurs through human intervention and the other occurs naturally in the environment.