Hobbies And Interests
Darwin's Natural Selection
Despite the popular association of Charles Darwin with the theory of evolution, he was not actually the first to develop such an idea; a number of evolutionary theories had been proposed over the previous century. What set Darwin apart was his discovery of the mechanism of natural selection, by which evolution takes place. Darwin proposed that organisms gradually change and adapt to exploit new food sources or new environmental niches, and that those adaptations that confer a reproductive advantage would be passed down to the next generation. Evolution was not a new idea, but Darwin was the first to see how it might happen.
Mendel's Genetics
Gregor Mendel was an Austrian monk who was also an avid gardener. In the mid-19th century he cultivated and studied pea plants in his monastery's garden. He observed how traits were expressed and inherited from one generation to the next, eventually deducing the existence of what are now called dominant and recessive genes. His 1865 paper on hybridization included laws of inheritance that are now considered the foundation of genetics. At the time, however, his work was largely ignored, and its importance was not recognized until years after his death.
Filling the Gap
By the early 20th century, Darwin's work was largely out of favor. Although he had deduced how evolution took place, he did not explain how the variation in species arose in the first place. Other theories suggested that organisms underwent regular change toward some goal, or that physical changes in one generation could be inherited by the next. In the 1930's, Theodosius Dobzhansky solved this problem. He showed that different populations of fruit flies had different genetic profiles, and that these could be replicated in the laboratory. In essence, he proposed that regular mutations provided a steady source of new adaptations. Most of these would be harmful, but a few would confer an advantage -- and so have a better chance of being passed along.
The Modern Synthesis
Dobzhansky's work, building on the genetics discovered by Mendel to solve the most serious problem in Darwin's evolutionary theory, pioneered the new science of evolutionary genetics. Soon, other scientists were extending Dobzhansky's research to include results from natural history and paleontology, eventually putting all of these together into a grand universal system of evolutionary biology. Dobzhansky's synthesis of Darwin and Mendel became the foundation of modern biology.