The famed British naturalist Charles Darwin was born on February 12, 1809, in Shrewsbury, England. Remarkably, Abraham Lincoln was born on the very same day. It’s hard to imagine a better day—or a more consequential day—for humanity.

Darwin began his work at an auspicious moment during the Age of Enlightenment, a time of rapid and revolutionary progress in science. He was born when a few early geologists were beginning to grasp that the world is truly ancient. Just twenty-one years prior, James Hutton, a Scottish geologist, penned these words, “The Earth reveals no vestige of a beginning, no prospect of an end.” Before that, even the most learned scholars in Europe thought the Earth was about 6,000 years old. Hutton’s startling conclusion, backed by a lifetime of observational evidence, gave us the concept we now call Deep Time.

When Darwin boarded the H.M.S. Beagle, two days after Christmas in 1831, beginning his five-year voyage around the world, he had not yet understood the antiquity of our planet. Like most others, he thought the Earth was quite young. Had he remained steadfast in this view, I dare say you would never have heard of Charles Darwin—his ideas, as we know them, would have made no sense on a young planet, and he would not have formulated them. However, on the way to South America, Darwin—ever a sponge for information—devoured a copy of Charles Lyell’s just-published Principles of Geology. Lyell had built upon Hutton’s work and was an elegant writer, and had a much wider audience. The concept of Deep Time shook Darwin to his bones. So much so that many years later, upon Lyell’s death, Darwin wrote, “I never forget that almost everything which I have done in science I owe to the study of his great works.”

Why did Darwin, who revolutionized an entire field of science, place so much value on Lyell’s work? Because Deep Time gave Darwin a crucial insight: given enough time, the tap-tap-tap of raindrops, the swash and backswash of the sea, and the lazy meandering of the tiniest stream can wear away mountaintops, shape and reshape coastlines, and cut deep into the Earth, entrenching vast canyons across the landscape. Darwin brilliantly applied this understanding of the physical world to the living world–to life. Given enough time, he reasoned, wouldn’t minuscule changes in organisms, amplified by Deep Time, add up to revolutionary changes? Everything didn’t have to happen at once. There was an incomprehensible sea of moments with which to work.

This led Darwin to two key understandings. The first is that populations of organisms can speciate over time. He reasoned that if a population was separated by a barrier—such as a sea or a chasm—populations on either side could become so distinct that they would eventually lose their ability to successfully breed with one another. When this happens, one species becomes two. Darwin then imagined running this process backward through time. If species beget species, then if we reverse the story of life, fewer and fewer species would exist as we go back, until finally we are left with a single common ancestor. This concept is now a foundational principle of biology, and it has been confirmed through paleontology and genetics with innumerable observations and experiments.

Darwin’s second key understanding was evolution through natural selection. He reasoned that natural variation exists within any population of organisms. Some rabbits are a little faster than others. Some bison are a little bigger. Some songbirds whistle a tune that lands a bit sweeter on the ears of potential mates. Any variation, Darwin thought, that resulted in slightly more reproductive success for the bearers of that trait would be favored over time. The change from one generation to the next would be largely imperceptible, but given enough time—vast swaths of time, Deep Time—the changes would add up. This simple, yet profound idea is called natural selection, and it is the main engine of evolutionary change within populations.

Darwin’s two great discoveries—common descent and evolution by natural selection—form the bedrock of the life sciences. It’s why the great 20th-century geneticist Theodosius Dobzhansky said, “nothing in biology makes sense except in the light of evolution.” The philosopher Daniel Dennett called Darwin’s concept of evolution through natural selection “the single best idea anybody ever had.” Indeed, Darwin’s accomplishments sit today as the foundations of all of life science. I think of it this way: Darwin created the operating system. Medicine, genetics, psychology, ecology, paleontology, and all the rest are the apps.

It’s not surprising, then, that Darwin’s ideas are well represented in the exhibits, merchandise, and programs of the Edelman Fossil Park & Museum. Common descent is an organizing principle of paleontology, and is often expressed as “family trees,” or what we in science call phylogenies. You’ll see lots of phylogenies in our galleries and in Critter Cove, our live animal center. Discovery Forest is a walk-in cabinet of curiosities, filled with drawers to explore, things to touch, and films on a wide array of science. Here, visitors can learn about various kinds of evolution, all driven by natural selection. And, of course, Darwin & Co., our museum store. It features a beautifully curated selection of nature-inspired books, toys, and naturalistic décor for your home. The centerpiece of the store is a kids’ area dubbed Darwin’s Study. It was inspired by Darwin’s actual study in his home, called Down House, south of London. It features portraits of James Hutton and Charles Lyell, as well as Mary Anning—a contemporary of Darwin’s and a legendary fossil collector. One wall in Darwin’s Study features a photograph, taken by me, of the sand path behind his country home.

Darwin was in the habit of walking a mile a day on the quarter-mile sand path—four times around—as he contemplated the mysteries of life, composing parts of “On the Origin of Species” in his head. Darwin was, like many scientists, frequently lost in his thoughts. Knowing this about himself, he would set up four rocks at the start of his walk. Each time around, he would kick one down, and after four were knocked down, he’d have walked a mile.

Darwin was a good family man and loved his children. And they loved their father—and would play tricks on him. On occasion, they would slip out from behind the verge and stand back up the rocks he’d already kicked over. To their great amusement, as long as the rocks remained standing, Darwin would keep walking.

Although he may have had “the single best idea anybody ever had,” he was still just a father to them. So on this Darwin Day, we celebrate the scientist, the explorer, and, yes, the goofy dad that was Charles Darwin.

A marauding Dryptosaurus towers over the phylogeny of the dinosaurs, showing their common descent from an ancestor that lived about 137 million years ago.

You’ll see many other depictions of common descent in the galleries, including this artistic take on dinosaur phylogeny, which aptly shows evolution as a set of forks in the road.

Several electronic interactives show evolution in action. In them, visitors can see how variation within a population leads to some genes being transmitted into the future more than others—a process Darwin called natural selection.

Discovery Forest is a great place to learn about natural selection.

Charles Darwin wasn’t always the bearded, wizened sage of evolution, as he is so often depicted. When he left on his five-year voyage around the world, he was a restless 22-year-old in search of adventure—and perhaps some distance from his father, who told him, “You care for nothing but shooting birds, dogs, and rat-catching, and you will be a disgrace to yourself and all your family.”