Charles Darwin’s theory of evolution is one of the most significant scientific discoveries in the history of mankind. This theory transformed our understanding of the natural world and is still impacting our lives today. In this article, we will explore what Darwin’s theory of evolution was and how it works.

The Basics

Darwin’s theory of evolution is based on the idea that all living organisms evolved over time from a common ancestor. This process occurred through natural selection, which means that certain traits that are advantageous for survival are more likely to be passed down to the next generation.

Natural Selection

Natural selection is the process by which organisms with favorable variations are more likely to survive and reproduce than those with less favorable variations. These favorable variations are called adaptations and can occur through genetic mutations or changes in an organism’s environment.

For example, consider a population of birds living on an island with different beak sizes. If there is a drought and only large seeds are available, birds with larger beaks will have an advantage over those with smaller beaks because they can crack open the larger seeds more easily. As a result, over time, the population will evolve to have larger beaks as these traits are passed down to future generations.

Common Descent

Darwin’s theory of evolution also suggests that all living organisms share a common ancestor. This means that every species on earth today has evolved from a single-celled organism that existed billions of years ago.

This idea is supported by evidence from molecular biology, genetics, and comparative anatomy. For example, all living organisms use DNA as their genetic material, suggesting a common origin for all life on earth.

The Tree of Life

Darwin’s theory of evolution can be visualized through the concept of the tree of life. The tree represents the evolutionary relationships between different species.

At its base, the tree represents the common ancestor of all life on earth. As you move up the tree, each branch represents a different species that has evolved from its ancestors. The closer two branches are on the tree, the more closely related those species are.


Charles Darwin’s theory of evolution is a fundamental concept in biology and has revolutionized our understanding of the natural world. By explaining how all living organisms are related and how they have evolved over time, this theory has helped us better appreciate the diversity of life on earth. Through natural selection and common descent, Darwin’s theory has provided us with a framework for understanding how life works and how it has changed over time.