Students ask: “Do Darwin’s finches show evolution in action?”

The 10th-grade California biology textbook, Biology by Miller & Levine, says, “One way to gather evidence for evolutionary change is to observe natural selection in action. But most kinds of evolutionary change we’ve discussed so far [i.e. land mammals to whales] took place over millions of years—which makes it tough to see change actually happening.”1

Darwin's Finches.001

Evolution involves the formation of new structures and information, not variation.

The book then proceeds to tell how research on the finches of the Galapagos Islands off the west coast of South America are a case-example of natural selection in action. “…Darwin’s hypothesis [about finch beaks] rested on two testable assumptions. First, for beak size and shape to evolve, there must be enough heritable variation in those traits to provide raw material for natural selection. Second, differences in beak size and shape must produce differences in fitness…there is indeed great variation of heritable traits among Galapagos finches.”2

Variations in beak size may be selected for by natural selection, since some beak varieties may benefit a finch in a certain environment, for example in a season of drought. It has been shown by researchers Peter and Rosemary Grant “that natural selection takes place in wild finch populations frequently, and sometimes rapidly.”2

While this type of change is clearly observable, is it really “evolutionary” in the same way as the change from land mammals to whales? The former change occurs through variation in structures that already existed, however, the latter change supposedly occurred by the addition of new structures, i.e. flippers, fins, etc. This type of change, as admitted by the textbook, is unable to be observed. In fact, the sizes in Galapagos finch beaks have been shown to bounce back and forth when the environment changes, thus no net-change, and the finches remain as finches.3

Since no new structures are being produced and no new information is being added to the DNA, only ‘selected’ for by natural selection, is it really accurate for textbooks to call these changes “evolutionary”? No; rather, the variety in finch beaks testifies to the amazing design and wisdom of God, who foresaw the environments His creatures would live in and gave them the ability to adapt and “fill the earth” in accordance with His commands.

Free Resources for Further Reading:

Chapter 6: Natural Selection and Evolution: Do Darwin’s Finches Prove Evolution?

ICR: Do Darwin’s Finches Prove Evolution?

Natural Selection vs. Evolution


1Miller, Kenneth R., and Joseph S. Levine. Miller & Levine Biology. Boston, MA: Pearson, 2006. 471. Print.

2Ibid. 472

3Brian Thomas, 2014. Do Darwin’s Finches Prove Evolution?Acts & Facts. 43 (11).