A group of birds known as Darwin’s finches (genus Geospiza) lives in the Galápagos Islands in the Pacific Ocean 600 miles west of Ecuador. These birds got their fame from Charles Darwin’s visit to the Galápagos in 1835.¹ When Darwin later examined the finches he collected, he believed their beak variation was evidence for his theory of gradual evolution by natural selection.

While several authors wrote about Galápagos finches after Darwin, serious research did not occur until 1973 when a Princeton University husband and wife team, Peter and Rosemary Grant, began using them as an evolutionary model system. They carefully monitored the populations of various finch species, focusing primarily on the Galápagos island Daphne Major, which was well-isolated from human interference compared to the other islands. The Grants recorded weather patterns, the birds’ diets, and changes in body and beak size/shape over 40 years.²

The Grants initially discovered that weather cycles affected beak traits. Droughts caused plants to produce tough seeds that in turn affected the finch beaks. Finches with smaller beaks couldn’t crack the seeds and therefore starved, while the few with larger beaks could crack open the seeds and survived. Thus, depending on the seasonal weather patterns, the beak traits cycled back and forth.

Adaptive Genetic Variation

Medium ground finch, Geospiza fortis, Puerto Egas, James Island, Isla Santiago, Santiago Island, Galápagos

Image credit: Gerald Corsi | iStock

A 2022 study included a comprehensive analysis of DNA sequences associated with traits such as beak and body size.³ Researchers discovered that in the small, medium, and large ground finches there were 28 different chromosomal regions (loci) exhibiting genetic variation that was connected to beak development and body size.

Several of the same researchers had earlier sequenced DNA from 120 different individuals representing all of Darwin’s finches and two close relatives. Their 2015 study found “extensive evidence for interspecific gene flow throughout the radiation [diversification].”⁴ Concerning adaptive interbreeding, the study authors wrote,

Extensive sharing of genetic variation among populations was evident, particularly among ground and tree finches, with almost no fixed differences between species in each group.⁴

Small ground finch, Geospiza fuliginosa, Galápagos

Image credit: Gerald Corsi | iStock

Other researchers later used whole genome data from 3,955 of Darwin’s finches representing four species on Daphne Major.⁵ They discovered that six major loci explained 45% of the observed variation in beak size. The most prominent locus was a region containing four genes that carried enough variation within it to cause a rapid adaptive shift in the population in response to the drought conditions that altered the food supply.

Adaptive Epigenetics

Epigenetics is another important mechanism in adaptation. It involves the addition of chemical tags in the genome that don’t change the actual genetic code. For example, adding a methyl group to cytosine nucleotides (methylation) changes gene expression.

In a 2014 study of Darwin’s finches, researchers examined genome-wide patterns of DNA methylation.⁶ They found that methylation patterns—not DNA sequence variation—correlated with increased trait diversity. Researchers also examined epigenetic profiles of specific genes involved in the morphogenesis of beak shape, immune responses, and coloring, showing that these traits again varied due to epigenetics, not DNA sequence.

In a 2017 study, researchers collected data from over 1,000 birds from the Geospiza fortis and G. fuliginosa species of Darwin’s finches.⁷ The birds were separated into two different groups that lived on Santa Cruz Island in the Galápagos, which had a significant human population. One of the finch populations was rural and ate food in the wild. The others were urban and had adapted to human food.

The researchers found that urban G. fortis finches were larger in body size and beak shape compared to rural G. fortis due to increased food availability at the urban site. The two different G. fuliginosa populations showed no significant physical changes. However, they did discover dramatic DNA methylation differences between the urban and rural populations of both species, showing that food-source adaptation was regulated by epigenetics.

Conclusion

Evolutionists claim that random mutations and the mystical agent of natural selection fuels adaptation. However, science has shown that adaptation is best explained by built-in genetic variation and epigenetic control systems engineered by our Creator, the Lord Jesus.

References

1. Grant, P. R. and B. R. Grant. 2005. Darwin’s Finches. Current Biology. 15 (16): R614, 3.
2. Grant, P. R. and B. R. Grant. 2014. 40 Years of Evolution: Darwin’s Finches on Daphne Major Island. Princeton, NJ: Princeton University Press.
3. Rubin, C. J. et al. 2022. Rapid Adaptive Radiation of Darwin’s Finches Depends on Ancestral Genetic Modules. Science Advances. 8 (27): eabm5982.
4. Lamichhaney, S. et al. 2015. Evolution of Darwin’s Finches and Their Beaks Revealed by Genome Sequencing. Nature. 518 (7539): 371–375.
5. Enbody, E. D. et al. 2023. Community-Wide Genome Sequencing Reveals 30 Years of Darwin’s Finch Evolution. Science. 381 (6665).
6. Skinner, M. K. et al. 2014. Epigenetics and the Evolution of Darwin’s Finches. Genome Biology and Evolution. 6 (8): 1972–1989.
7. McNew, S. M. et al. 2017. Epigenetic Variation Between Urban and Rural Populations of Darwin’s Finches. BMC Evolutionary Biology. 17, article 183.

Stage image: Pinnacle Rock on Bartolomew Island, Santiago Island in the background, Galapágos
Stage image credit: DC_Colombia, iStock. Used in accordance with federal copyright (fair use doctrine) law. Usage by ICR does not imply endorsement of copyright holder.

Dr. Tomkins is a research scientist at the Institute for Creation Research and earned his Ph.D. in genetics from Clemson University