Chapter 15, Problem 8A

Summary Introduction

To sequence:

The events leading to evolution by natural selection.

Introduction: Darwin read an essay by Thomas Malthus that suggested that if the human population is unchecked, it would soon outgrow its food supply leading to a competitive struggle for existence. Darwin got the idea that this principle could also be applied to the natural world. He gave a new theory of natural selection that could explain the evolution of species.

Answer to Problem 8A

Natural selection is a mechanism to explain the theory of evolution developed by Charles Darwin. The sequence of events leading to evolution by natural selection includes:

1. Variation in species
2. Heritability of variations
3. Overproduction of offspring
4. Reproductive advantage
5. Evolution

Explanation of Solution

Charles Darwin gave a theory of natural selection. There are four basic principles of this theory.

1. Individual in a population shows differences with others of the same species. These differences are called variations.

2. Variations can be inherited, i.e., they can be passed down from parent to offspring.

3. Organisms often produce more offspring than can survive on available resources.

4. Some variations that increase reproductive success will have a greater chance of being passed on than those that do not increase reproductive success.

5. Finally, over time an entirely new species develops that has advantage over the old species. This is called evolution.

He argued that if enough time is given, natural selection could modify a population to produce new species. Later Darwin compiled evidences for evolution and explained that natural selection might provide a means of explaining how evolution works.