Renowned geneticist Theodosius Dobzhansky once said, “Nothing in biology makes sense, except in the light of evolution.” Though remarkable advances have been made in the 36 years since he made this observation, it still rings true. In the 150 years following Charles Darwin’s publication of On the Origin of Species, evolutionary thinking has been fundamental to every major biological discovery. Today, on Darwin’s 200th birthday, we pay homage to the father of evolution and one of the greatest scientific thinkers of all time.
Darwin deserves this title because he discovered the main mechanism by which evolution takes place, natural selection.
He began to understand this mechanism during the five years he traveled on the Beagle along the coast of South America. He discovered fossils of animals that no longer existed but closely resembled the organisms that now populated the land, such as armadillos and sloths. On the Galapagos Islands, he observed the incredible diversity of finches, such as in their beak structure, and how such unique characteristics made them best suited for their particular environments. On the Origin of Species was the culmination of more than two decades of Darwin’s thinking.
He observed that the offspring of an organism are not identical to one another but have slightly different characteristics. On this basis, he postulated that some of these characteristics would give the offspring an advantage of being better suited to survive in their environment. As organisms that did not possess this beneficial trait died out, these favorable characteristics would be naturally selected and passed on to future generations.
Darwin’s revolutionary discovery has inspired a whole new field of biology. Evolutionary biologists have gained a vast amount of knowledge about the natural world through fossil evidence, molecular phylogenetics, biogeography, and ecology. For example, we have learned that birds evolved from dinosaurs that developed feathers to keep warm. Sickle cell anemia occurs more often in people in Africa because possessing a sickle-cell allele protects these individuals from being infected with malaria, a disease rampant throughout the continent. Echinoderms, which include star fish and sea cucumbers, develop in utero very similarly to how dogs, giraffes, fish, and humans develop because they are one of our closest relatives.
All of this remarkable knowledge and much more is made possible because of the foundational knowledge of evolution given to us by Darwin. His theory of natural selection provides a rational basis for all biological processes and phenomenon. On his 200th birthday, we should recognize Darwin’s immense contribution to science. Ultimately, he has led us to answer questions that have haunted men for centuries, such as where we came from, how we got here, and why.
