by Heather Scoville Updated May 01, 2019

Imagine being the first person to discover and put together the pieces of an idea so big that it would change the entire spectrum of science forever. In this day and age with all of the technology available and all kinds of information right at our fingertips, this may not seem to be such a daunting task. What would it have been like back in a time where this previous knowledge that we take for granted had not yet been discovered and the equipment that is now commonplace in labs had not yet been invented? Even if you are able to discover something new, how do you publish this new and “outlandish” idea and then get scientists all over the world to buy into the hypothesis and help strengthen it?

This is the world that Charles Darwin had to work in as he pieced together his Theory of Evolution through Natural Selection. There are many ideas that now seem like common sense to scientists and students that were unknown during his time. Yet, he still managed to use what was available to him to come up with such a profound and fundamental concept. So what exactly did Darwin know when he was coming up with the Theory of Evolution?

1. Observational Data

Obviously, Charles Darwin’s most influential piece of his Theory of Evolution puzzle is the strength of his own personal observational data. Most of this data came from his long voyage on the HMS Beagle to South America. Particularly, their stop at the Galapagos Islands proved to be a gold mine of information for Darwin in his collection of data on evolution. It was there that he studied the finches indigenous to the islands and how they differed from the South American mainland finches.

Through drawings, dissections, and preserving specimens from stops along his voyage, Darwin was able to support his ideas that he had been forming about natural selection and evolution. Charles Darwin published several about his voyage and the information he collected. These all became important as he further pieced together his Theory of Evolution.

2. Collaborators’ Data

What’s even better than having data to back up your hypothesis? Having someone else’s data to back up your hypothesis. That was another thing that Darwin knew as he was creating the Theory of Evolution. Alfred Russel Wallace had come up with the same ideas as Darwin as he traveled to Indonesia. They got in contact and collaborated on the project.

In fact, the first public declaration of the Theory of Evolution through Natural Selection came as a joint presentation by Darwin and Wallace at the Linnaean Society of London’s annual meeting. With double the data from different parts of the world, the hypothesis seemed even stronger and more believable. In fact, without Wallace’s original data, Darwin may never have been able to write and publish his most famous book On the Origin of Speices which outlined Darwin’s Theory of Evolution and the idea of Natural Selection.

3. Previous Ideas

The idea that species change over a period of time was not a brand new idea that came from Charles Darwin’s work. In fact, there were several scientists that came before Darwin that had hypothesized the exact same thing. However, none of them were taken as seriously because they did not have the data or know the mechanism for how species change over time. They only knew that it made sense from what they could observe and see in similar species.

One such early scientist was actually the one that influenced Darwin the most. It was his own grandfather Erasmus Darwin. A doctor by trade, Erasmus Darwin was fascinated by nature and the animal and plant worlds. He instilled a love of nature in his grandson Charles who later recalled his grandfather’s insistence that species were not static and in fact did change as time passed.

4. Anatomical Evidence

Almost all of Charles Darwin’s data was based on anatomical evidence of various species. For instance, with Darwin’s finches, he noticed the beak size and shape was indicative of what kind of food the finches ate. Identical in every other way, the birds were clearly closely related but had the anatomical differences in their beaks that made them different species. These physical changes were necessary for the survival of the finches. Darwin noticed the birds that did not have the right adaptations often died before they were able to reproduce. This led him to the idea of natural selection.

Darwin also had access to the fossil record. While there were not as many fossils that had been discovered in that time as we have now, there was still plenty for Darwin to study and ponder over. The fossil record was able to clearly show how a species would change from an ancient form to a modern form through an accumulation of physical adaptations.

5. Artificial Selection

The one thing that escaped Charles Darwin was an explanation for how the adaptations happened. He knew that natural selection would decide if an adaptation was advantageous or not in the long run, but he was unsure of how those adaptations occurred in the first place. However, he did know that offspring inherited characteristics from their parents. He also knew that offspring were similar but still different than either parent.

To help explain adaptations, Darwin turned to artificial selection as a way to experiment with his ideas of heredity. After he returned from his voyage on the HMS Beagle, Darwin went to work breeding pigeons. Using artificial selection, he chose which traits he wanted the baby pigeons to express and bred the parents that showed those traits. He was able to show that artificially selected offspring showed desired traits more often than the general population. He used this information to explain how natural selection worked.


by Heather Scoville Updated January 21, 2019

Charles Darwin is known as the father of evolution. When he was a young man, Darwin set out on a voyage on the HMS Beagle. The ship sailed from England in late December of 1831 with Charles Darwin aboard as the crew’s naturalist. The voyage was to take the ship around South America with many stops along the way. It was Darwin’s job to study the local flora and fauna, collecting samples and making observations he could take back to Europe with him of such a diverse and tropical location.

The crew made it to South America in a few short months, after a brief stop in the Canary Islands. Darwin spent most of his time on land collecting data. They stayed for more than three years on the continent of South America before venturing on to other locations. The next celebrated stop for the HMS Beagle was the Galapagos Islands off the coast of Ecuador.

Galapagos Islands

Charles Darwin and the rest of the HMS Beagle crew spent only five weeks in the Galapagos Islands, but the research performed there and the species Darwin brought back to England were instrumental in the formation of a core part of the original theory of evolution and Darwin’s ideas on natural selection which he published in his first book . Darwin studied the geology of the region along with giant tortoises that were indigenous to the area.

Perhaps the best known of Darwin’s species he collected while on the Galapagos Islands were what are now called “Darwin’s Finches”. In reality, these birds are not really part of the finch family and are thought to probably actually be some sort of blackbird or mockingbird. However, Darwin was not very familiar with birds, so he killed and preserved the specimens to take back to England with him where he could collaborate with an ornithologist.

Finches and Evolution

The HMS Beagle continued to sail on to as far away lands as New Zealand before returning to England in 1836. It was back in Europe when he enlisted in the help of John Gould, a celebrated ornithologist in England. Gould was surprised to see the differences in the beaks of the birds and identified the 14 different specimens as actual different species – 12 of which were brand new species. He had not seen these species anywhere else before and concluded they were unique to the Galapagos Islands. The other, similar, birds Darwin had brought back from the South American mainland were much more common but different than the new Galapagos species.

Charles Darwin did not come up with the Theory of Evolution on this voyage. As a matter of fact, his grandfather Erasmus Darwin had already instilled the idea that species change through time in Charles. However, the Galapagos finches helped Darwin solidify his idea of natural selection. The favorable adaptations of Darwin’s Finches’ beaks were selected for over generations until they all branched out to make new species.

These birds, although nearly identical in all other ways to mainland finches, had different beaks. Their beaks had adapted to the type of food they ate in order to fill different niches on the Galapagos Islands. Their isolation on the islands over long periods of time made them undergo speciation. Charles Darwin then began to disregard the previous thoughts on evolution put forth by Jean Baptiste Lamarck who claimed species spontaneously generated from nothingness.

Darwin wrote about his travels in the book The Voyage of the Beagle and fully explored the information he gained from the Galapagos Finches in his most famous book On the Origin of Species. It was in that publication that he first discussed how species changed over time, including divergent evolution, or adaptive radiation, of the Galapagos finches.