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From Studying the Cloth to Fossils of Sloths
From Studying the Cloth to Fossils of Sloths
Charles Darwin, an Englishman, was well-positioned to become a scientist in his time - he came from an affluent background and originally intended to become a clergyman. His grandfather, Erasmus Darwin, was actually a renowned physician. In 1831, however, he received an invitation to serve as the naturalist aboard the HMS Beagle for an extensive trip around the world. Below is an image of the Beagle's voyage.
While aboard the ship, Darwin had few opportunities to entertain himself. One of the most influential parts of his trip has been said to have been a book by Charles Lyell, Principles of Geology. This book, and Lyell's theory of uniformitarianism has been credited with inspiring Darwin to consider the incredibly slow, unchanging laws that rule the natural world, one of which could be the idea of evolution.
He was only 22 years old at the onset of the voyage, so was certainly not the most experienced naturalist at this time. Darwin traveled for nearly five years aboard the Beagle, making careful observations and collecting (and sending home) specimens from South America and many islands. However, his most important conclusions primarily came from his observations in the Galapagos.
The Beagle completed its voyage in 1836, much to the relief of the oft-seasick Darwin. However, this was only the beginning of Darwin's evolutionary journey. In fact, Darwin would not publish his On the Origin of Species until 1859, a whole 23 years later! There is the very real possibility that Darwin's conclusions may never have been published had it not been for a letter from another naturalist, Alfred Russel Wallace. Before delving into Wallace's contributions, however, Darwin's observations warrant some exploration.
A Young Scientist's Observations
A Young Scientist's Observations
On his journey (originally planned to be 2 years long), Darwin took copious, detailed notes on many things from marine plankton to the now-prominent finches found on the Galapagos. While in the southern regions of South America, he made a major discovery of fossilized bones of large, extinct mammals (amongst other discoveries). Among these findings was a tooth of the Megatherium, or genus of giant ground sloths (some the size of elephants).
While exploring the relatively young, geologically speaking, Galapagos Islands, Darwin found bird variations somewhat similar to those in Chile, but found that they differed between islands significantly. This disparity amongst the islands became a pivotal aspect of his eventual findings.
Along those lines, he learned from locals that you could tell the island a particular tortoise came from by variations in their shell shapes. However, he was unable to make any collections of the tortoises.
Obviously, the collections and observations mentioned here are only a small sample of what he experienced on the nearly five-year voyage.
The collections he sent home along the way gave him some credence in the scientific community, but his most groundbreaking discoveries regarding evolutionary theory were still brewing upon his return in 1836, and would not be published for quite a long time yet.
From Observations to Conclusions
From Observations to Conclusions
Upon his return to England, Darwin wrote some scientific papers in the fields of geology and zoology based on his findings. He also had begun writing his Journal and Remarks, which now referred to most commonly as The Voyage of the Beagle, his narrative of the trip.
Ornithologist John Gould found that the Galapagos birds Darwin had collected were actually twelve unique species of finches, not simply variations of the same species. These birds, which would eventually be dubbed Darwin's finches, played a pivotal role in the formation and the presentation of Darwin's theory of natural selection.
After mapping the bird species to the appropriate islands and noticing their distributions with geography, Darwin started to think about evolution and the possibility that one species may change into another.
He began to sketch out branching descent, later called descent with modification, and created what is likely the first evolutionary tree.
However, due to health concerns, strict writing deadlines, and fear of backlast, Darwin would not publish these thoughts for years. Meanwhile, he continued his work in biology and geology, writing books and spending about eight years researching barnancles. Eventually, in 1859, he would release On the Origin of Species.
Before that is discussed, it is important to acknowledge that Charles Darwin was not the only individual making profound discoveries in evolution with immense implications for the field.
Alfred Russel Wallace - The Underdog
Alfred Russel Wallace - The Underdog
Alfred Russel Wallace, unlike Darwin, came from a less-than-affluent background. This did not stop him, however, from feeling inspired by Darwin's success (along with the stories of other traveling naturalists). Darwin was not actually known yet for his theory of natural selection - he would not publish this for many years. Rather, Darwin had amassed a prestigious reputation for the collections he had sent back home to England.
In 1848, Wallace began collecting specimens in South America, where he spent most of his career. He collected many specimens, primarily insects, in the Amazon rainforest to be sold to private collectors and museums. All the while, Wallace hoped to find data to elucidate the mysteries of the transmutation of species (a precursor to our current understanding of evolution).
Wallace worked on charting and collecting the Rio Negro for four years before beginning his return to the United Kingdom in 1852 aboard the Helen. After less than a month at sea, however, the ship caught fire. All of Wallace's specimens and most of his notes and sketches were lost in the fire. This fire destroyed the specimens collected in his most recent (and most interesting) two years of work. Wallace and the crew were eventually rescued and he returned to London for 18 months. During this time, he did write some academic papers before preparing for further travels in the Malay Archipelago.
While exploring the archipelago and collecting over 125,000 specimens, Wallace continued to refine his thoughts of evolution and actually came up with a mechanism by which it occurs. However, Wallace wanted a second opinion, so he sent a letter to the renowned Charles Darwin in 1858 outlining his findings.
To Darwin's surprise, Wallace had formed the same conclusions he himself had years previously - theory by a process that would come to be known as natural selection.
Darwin was shocked that someone else had made the same discoveries, but he was invigorated by the letter. Darwin had formed his ideas about natural selection years previously but had left them unpublished, likely due to an understandable fear of backlash.
Sharing the Credit - Equal on Paper Alone...
Sharing the Credit - Equal on Paper Alone...
Wallace's letter shocked Darwin into action, lest another scientist publish this momentous theory before he had the chance. However, Darwin was not able to contact Alfred Russel Wallace due to his aforementioned travels in the Malay Achipelago.
It was decided (with input from Wallace's trusted colleagues) that the ideas be presented jointly in 1858 to the Linnean Society as On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection. Darwin, however, was too distraught to attend due to the recent death of his infant son due to scarlet fever.
The theory did not make a big splash initially, and remained overlooked for over a year. In 1859, despite illness, Darwin published On the Origin of Species, and it was shockinging popular. Only 1,250 copies were published initially, and it sold out rapidly.
Despite the fact that Alfred Russel Wallace and Charles Darwin had independently formed the same theory and presented their ideas jointly, Darwin certainly receives most of the credit for the discovery. Wallace, by all accounts, was not bothered by this disparity, however, and continued to idolize Darwin throughout his life.
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