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Celebrating Darwin Day

Gorilla

Scientists around the world celebrate Darwin Day each year on February 12th, Charles Darwin’s birthday. This event not only celebrates the work of this amazing geologist and biologist but aims to highlight the importance of scientific study across all fields. Darwin is of course best known for his ground-breaking work, On the Origin of Species. There was more to his life and career than that, however.

Evolution by Natural Selection

Darwin’s most famous work, On the Origin of Species, 1859, details his theory of natural selection. This states that the natural variation of individuals within a species make them better or worse adapted to their environment. Those with traits that are better suited survive to pass them on, those that don’t, die out. This is the nuts and bolts of evolution. His ideas were prompted by a combination of his geological knowledge and a five-year voyage on HMS Beagle between 1831 and 1836. It was on this voyage that he collected the now-famous Galāpagos finches and a fascination with barnacles was kickstarted.

Limpets and barnacles
Darwin was fascinated by barnacles and they helped him with his theory of natural selection

Although he had come up with the basic theory by 1838, he spent the next 20 years researching evidence to back his ideas up, while also still focusing on other areas of enquiry. Then, fellow biologist Alfred Russel Wallace wrote to him with similar thoughts in 1858. Consequently, the two presented their theories together to the Linnean Society. This cooperation was incredibly important to Darwin. That the two men could come up with similar theories independently of each other, yet feel no rivalry, showed that scientific work without ego could exist. Darwin’s 1871 work, The Descent of Man, then put forward the theory that humans and apes have a common ancestor. Contrary to popular belief, he never actually said that we evolved from monkeys.

Darwin the Geologist

Although the importance of his theory of natural selection means we often think of Darwin as primarily a biologist, he was also a geologist. In fact it was partly his decision to focus on geology that meant he took so long to publish his book on natural selection. Much of his work centred on landforms seen on the Beagle voyage, such as coral reefs and atolls. However, in 1838 he travelled to Glen Roy near Fort William, Scotland to view a geological feature that had puzzled many scientists.

Glen Roy Parallel Roads
The straight lines on the sides of Glen Roy puzzled many geologists

On either side of the glen are a series of parallel lines, dubbed ‘roads’ that no one could explain. Darwin thought the lines were marine features and showed different stages of the land rising from the sea. Swiss geologist Louis Agassiz solved the mystery, however. He suggested that the lines instead showed where glacial lakes had once stood.

Glen Roy Geology
The lines show the levels glacial lakes once reached

Birds, Beetles and Barnacles

One of the projects holding up publication of On the Origin of Species was a study of barnacles. Darwin spent eight years between 1846 and 1854 on these crustaceans. The result was a four-volume monograph on both living and extinct species. Some of this work helped inform his work on evolution. He began to see the variations that existed within a single species. He also saw anatomical features that existed across many species, suggesting a common ancestor.

Pigeons
Darwin’s domestic pigeons revealed a lot about variation and inheritance

Research on domestic animals, including pigeons, also helped Darwin to develop his theory of natural selection. He bred many varieties himself, and their variations showed him how traits could be passed to successive generations. As well as playing a part in On the Origin of Species, pigeons featured even more heavily in his 1868 work, The Variation of Animals and Plants Under Domestication. This was essentially a book exploring unnatural, or artificial, selection, as opposed to natural.

Dor beetle
Darwin started a large beetle collection at university

As well as a fondness for pigeons, beetles fascinated Darwin. While studying at Cambridge in the late 1820s, he collected a huge collection. Some of his collection can still be seen at the university’s Museum of Zoology. Some people have attributed a quote to Darwin suggesting that if God had created all the world’s creatures, he must be ‘inordinately fond of beetles’ due to the huge number of species. Sadly, it is more likely to have come from the later biologist and geneticist JBS Haldane, if anyone.

The World of Worms

Darwin’s last work was The Formation of Vegetable Mould Through the Action of Worms, published in 1881. Like many of his publications, it was groundbreaking. The book showed how important worms are for producing good quality soil for plants to grow in. It also revealed just how complex these deceptively simple organisms are. Despite its superficially niche subject matter, the book sold thousands of copies in just a few weeks.

Earthworm
Earthworms were the basis of Darwin’s final work

Darwin Day

Charles Darwin died in 1882. His legacy, however, lives on. As well as helping to develop one of the most important ideas in science’s history, evolution through natural selection, he worked in a diverse range of fields with an inspirational dedication to scientific principles. His championing of, and cooperation with, Wallace represents the very best of science as collaboration. At a time when scientific enquiry often feels more threatened than ever by misinformation and conspiracy theories, his legacy is more important than ever.