Citation
How and Why Species Multiply: The Radiation of Darwin's Finches
TL;DR
~18 species from single ancestor over 2-3 million years
Comprehensive account of Darwin's finch radiation based on four decades of field research by the Grants. Documents the approximately 18 species that diversified from a single ancestor arriving in the Galápagos ~2-3 million years ago, each adapted to different food sources.
Provides detailed evidence for how ecological opportunity, character displacement, and reproductive isolation drive adaptive radiation in real time.
Key Findings from Grant & Grant (2008)
- ~18 species from single ancestor over 2-3 million years
- Each species adapted to different food sources
- Documented natural selection in action during drought years