What Was Wallace’s Theory of Evolution by Natural Selection?


Jane Flores

Wallace’s Theory of Evolution by Natural Selection

Charles Darwin is widely known for his theory of evolution by natural selection, but what many people don’t realize is that he was not the only one to come up with this idea. In fact, another naturalist named Alfred Russel Wallace independently developed the same theory around the same time. So, what exactly was Wallace’s theory of evolution by natural selection?

Wallace’s Background and Contributions

Alfred Russel Wallace was born in January 1823 in Wales. He became interested in natural history at a young age and spent much of his life traveling to different parts of the world to study plants and animals. In the mid-19th century, Wallace began corresponding with Charles Darwin, who was also a naturalist and had similar interests.

In 1858, Wallace sent Darwin a letter outlining his theory of evolution by natural selection. Darwin was surprised to see that Wallace had arrived at the same conclusion independently. The two men presented their ideas together at a meeting of the Linnean Society in London later that year.

The Basics of Wallace’s Theory

So, what did Wallace’s theory actually say? Like Darwin, he believed that species change over time through a process called natural selection. This means that individuals with advantageous traits are more likely to survive and reproduce than those without those traits.

Wallace also recognized that there is variation within species – not all individuals are exactly the same. Some might have slightly longer legs or be able to digest certain foods more easily than others. These variations can be passed down from generation to generation through genetic inheritance.

According to Wallace’s theory, over long periods of time, these small changes can add up and eventually lead to the formation of new species. For example, imagine a population of birds where some have slightly longer beaks than others.

If food becomes scarce and only birds with longer beaks are able to survive, then over time the average beak length of the population will increase. This could eventually lead to the development of a separate species with longer beaks.

Differences between Wallace’s and Darwin’s Theories

While Wallace’s theory was similar to Darwin’s, there were some key differences. For example, Wallace believed that natural selection was not the only factor driving evolution – he also thought that there were other forces at work, such as sexual selection (where individuals with certain traits are more attractive to potential mates).

Wallace also believed in a type of Lamarckian evolution, which states that organisms can pass on traits acquired during their lifetime to their offspring. Darwin did not agree with this idea.


Despite these differences, both Darwin and Wallace played important roles in developing our understanding of evolution by natural selection. Today, their theories continue to be studied and refined by scientists all over the world. Understanding these concepts is crucial for anyone interested in biology or the history of science.