Charles Darwin’s theory of evolution by natural selection is one of the most influential scientific concepts in modern history. It explains how species have evolved and adapted over time, and has shaped our understanding of the natural world.

But what evidence did Darwin use to support his theory? In this article, we’ll explore some of the key pieces of evidence that Darwin used to develop his revolutionary theory.

The Galapagos Islands

One of the most important pieces of evidence that Darwin used to support his theory was his observations on the Galapagos Islands. During his voyage aboard HMS Beagle, Darwin noticed that different islands had distinct species of finches with different beak shapes. This led him to formulate the idea that these finches had evolved from a common ancestor and adapted to their respective environments through natural selection.

Darwin also observed other unique species on the Galapagos Islands such as giant tortoises and marine iguanas which further supported his theory.

Fossil Records

Another key piece of evidence for evolution comes from fossil records. Fossils provide a window into past life on Earth and show how species have changed over time.

When studying fossils, Darwin noticed that certain species appeared to be related to each other through a series of gradual changes. This suggested that they had evolved from a common ancestor rather than appearing fully formed as some believed at the time.

Artificial Selection

Darwin also observed how humans have artificially selected plants and animals for desirable traits such as bigger fruits or stronger livestock. He realized that this process was similar to natural selection in that certain traits were being favored over others leading to changes in the population over time.

Anatomical Similarities

Finally, Darwin noted striking similarities between different species’ anatomies which suggested they shared a common ancestor. For example, all mammals have similar bone structures in their limbs, despite their different functions, which suggests they evolved from a common four-limbed ancestor.


In conclusion, Darwin used a range of evidence to support his theory of evolution by natural selection. His observations on the Galapagos Islands, fossil records, artificial selection, and anatomical similarities all helped him formulate his revolutionary idea. Today, the theory of evolution remains one of the most important concepts in biology and continues to be supported by a wealth of scientific evidence.