Nearly 150 years after he proposed it, Charles Darwin's theory of evolution remains controversial, even though most scientists today accept it as biological fact. A major new museum exhibit in New York examines the scientific evidence for evolution, and attempts to understand Charles Darwin both as a scientific genius, and as a man.
At a press opening for "Darwin," one of the American Museum of Natural History's biggest shows in recent memory, Randal Keynes, Darwin's great-great grandson, stands between two exhibits that would certainly have pleased his famous ancestor.
To his left is a pair of live giant Galapagos tortoises, one of many species first recorded by Charles Darwin as a young naturalist aboard the HMS Beagle during its five-year voyage around the world from England through the southern oceans. To Mr. Keynes' right is a full-scale model of the laboratory and study where Darwin wrote his landmark book, On the Origin of Species.
"He was a man of passion," muses Mr. Keynes, "which is a bit of a surprise for many people who think of the elderly gray-bearded figure looking very severe," he says pointing to a famous portrait of the naturalist taken toward the end of his long life. "I think he remained a child all his life with his enthusiasm for the natural world, the beetles that he first collected and then for everything he went on to study. He was intensely ambitious. He wanted to find great truths in the wonderful variety of nature. And boy did he find one!" Mr. Keynes beamed.
That would be the theory of evolution, which states that all life on earth is descended from a single common ancestor, and that species change over time, through a process called "natural selection." In other words, organisms that adapt best to their environments tend to survive and produce offspring with those traits. This is in sharp contrast to prevailing Christian views, which held that God had created humans and animals in an unchanging form, over seven consecutive days.
Although Darwin wanted to become a clergyman, he came of age in an era where religious views of creation were being challenged. And Europeans were getting their first chance to see exotic animals - notably the "Great Apes."
So, says, Mr. Keynes, Charles Darwin took a trip to the London Zoo "And watched a young orangutan called Jenny, he watched her with the question in mind 'is she like a human child or is she different, and he just saw that she was so like a human child." Mr. Keynes adds that his ancestor's "great bravery" was to say "'I'm going to take that further. I'm going to look at that possibility and see whether it's a clue, and what it might mean for human nature and how we can understand ourselves…' and just didn't flinch at explaining it." Mr. Keynes says that was the mark of greatness. "Without that courage, he would have missed the full reach of his theory."
The theory of evolution is still controversial in places where the Bible is taken as literal truth. (In fact, the American Museum of Natural History has reportedly had difficulty finding a corporate sponsor for the Darwin exhibit after it became the target of criticism by conservative religious groups.)
But rather than get bogged down in that debate, museum official Michael Novacek says the exhibit attempts to focus on scientific evidence for evolution, and "co-evolution" as Darwin formulated them.
Mr. Novacek mentions Darwin's discovery of an orchid with flower nearly a third of a meter deep, and his surmise that some insect must have evolved with a proboscis long enough to drink the nectar and fertilize the flower.
"… And lo and behold, many years after, in the 20th century, the moth with that proboscis was discovered. It's in the show here. So the predictive powers, based on Darwin's observations are tremendous," he says.
Darwin's theory was general enough to include minutely small organisms and their relationship with their much larger hosts. For example, the current concern about the bird flu virus and its potential to mutate - that is, evolve - is based on knowledge first advanced by Charles Darwin.
"We know that you can only get avian flu from getting in contact with a chicken or a bird species with it," says Mr. Novacek. "That's bad enough. We don't transfer it from one human to another, which is really bad! But from the infective agent's point of view, the virus' point of view, its going to say 'to be more adaptive, maybe I'll switch hosts, and I'll adapt to a system where humans are transferring to each other.' We wouldn't even have a concept of that or a worry of that without Darwin's theory of evolution."
As scientific knowledge of the natural world deepens, and as the applications for Darwin's insights become refined, just what is meant by evolution and its reach may itself evolve. Whatever the case, it is clear that, nearly two hundred years after his birth, Charles Darwin's ideas retain their power to inform - and to stir debate.