Darwin's Finches
In September of 1835, Charles Darwin arrived at the lonely Galapagos Islands. His job was to collect specimens of plants and animals, and make notes about the rocks and climate.
When he got back to England, an expert on birds told Darwin that his collection from the Galapagos included 13 species of finch. All were unique to those islands—they could not be found anywhere on Earth.
This got Darwin to thinking. Why would there be so many unique species on these tiny, isolated islands? The finches were very similar, except for their beaks, and this provided a clue. At one extreme was a species with a huge beak for cracking large seeds. At the other extreme was a species with a sharp beak for snapping up insects. The beaks of the other species fit in between. For Darwin, this meant that all the species were related. How did this happen?
A long time ago, so the story goes, a freak storm blew a flock from South America. Some finches had beaks better suited to eating insects. Others had beaks better suited to drinking the nectar out of cactus flowers. Each finch found the food that suited its beak the most. Finches with similar beaks stayed together because they ate the same food in the same place. Eventually, one flock became 13 separate species.
Darwin called this natural selection. It was nature “selecting” the best birds to eat cactus flowers, or the best birds to eat insects.
At the time, all Darwin could do was tell the story. He had no proof that it happened in this way. But in recent years, other scientists have gone back to the Galapagos. They found that the islands experience long periods of drought interrupted by very wet years. When the rain comes, there’s plenty of food to go around. But during the dry years, tiny differences in the size of a beak can mean life or death.
Is this the proof Darwin needed? Not really. In this experiment, which took several years, nature did nothing more than change beak sizes. Perhaps, if given more time, nature could make a new species of finch in this way.
But what about the finch itself? Could nature make a whole new creature, not just a new species? Darwin thought it could. If nature could explain 13 species of finch, he thought, then nature could explain every species that ever lived.
But how? We have seen natural selection juggling beak sizes, but this is a long way from making every kind of creature that ever lived.
The studies on the Galapagos show us that nature can make small changes. Perhaps nature could make different types of finches, but God had to make the finch.
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