Friday, July 1, 2011

Happy Birthday, Biology!

July 1, 1858:
 
"The Linnaean Society of London listens to the reading of a composite paper on how natural selection accounts for the evolution and variety of species. The authors are Charles Darwin and Alfred Russel Wallace. Modern biology is born."

Darwin had waited for 20 years to publish his carefully recorded data that would become On the Origin of Species. To his horror, he discovered that another naturalist, Alfred Russel Wallace, had discovered Natural Selection independently and was about to publish his paper on the subject. He had come to the exact same conclusions that Darwin had, that the mechanism of evolution is natural selection, although Wallace had much less data. They met and agreed to publish a joint paper to the Linnaean Society. Darwin pushed out his book Origin the following year which outlined Natural Selection in great detail.

It might seem that maybe Wallace had heard of Darwin's work and tried to jump in and steal it but that's not what happened. Someone was going to come up with Natural Selection sooner or later, mainly because it's written all over the natural world. The evidence was piling up rapidly by the 1850's. Evolution itself was already well established by direct observation - now the race was on for the mechanism driving it. Many naturalists were closing in on the solution. In fact, Charles' grandfather Erasmus Darwin had his own ideas on descent with modification, as did several others, before Charles was even born. So it's not really that coincidental. The reason we remember Darwin for the work is because he had taken the time to anticipate legitimate challenges to his theory, holes if you will, and get the evidence he would need to defend it ahead of time. By the time he published Origin, he was sitting on a veritable mountain of data from hundreds of sources and he was very, very sure he was right.

The same thing happened to Isaac Newton - a guy named Gottfried Wilhelm Leibniz invented The Calculus at just about exactly the same time Newton did. Science tends to converge on major structural discoveries rapidly once the foundations are all in place. One discovery can sometimes be the missing puzzle piece that solidifies an entire theory.
Ironically, at about the same time Darwin was gathering his data for Origin, a monk named Gregor Mendel was experimenting with hybridizing pea plants and carefully recording his startling and unexpected findings - this data would one day form the basis of modern genetics. I'm sure Gregor had no idea how important his findings really were, that they would eventually provide the missing puzzle piece that would solidify evolutionary theory.
 
The fusion of genetics and evolution was accomplished in the 1930's, and it was a perfect fit - genetics provided an explanation for the one big mechanism Darwin couldn't explain in his lifetime: his theory required that the properties of mother and father be combined to form a new organism with traits from both but without a tendency to "average" the features over time and lose specific traits. Studies in Genetics revealed that this is accomplished via the inheritance of discrete pieces of information that we now know as genes. Genes turned out to be the biological mechanism that natural selection works on in the natural world to produce change in organisms.
 
It is no understatement to say that the combination of genetics and evolution is now one of the great scientific accomplishments of humanity. It is now called the Modern Synthesis, and is the foundation of modern biology.

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