What evidence did scientists use to determine that all 13 species of finches on the Galapagos have one common ancestor?
Scientists used several lines of evidence to determine that all 13 species of finches on the Galapagos have one common ancestor. These include:
1. Genetic analysis: Researchers have compared the DNA of different Galapagos finch species and found that they all share similarities in their genetic makeup. This suggests that they are all descended from a single ancestral population.
2. Morphological analysis: Scientists have studied the physical traits of each finch species, such as beak size and shape, and found that they show variation that is related to their specific diets and behaviors. However, they also share many common features, such as the shape of their wings and the structure of their feathers, which suggest a common ancestry.
3. Fossil evidence: While there are no known fossils of Galapagos finches from before the arrival of humans on the islands, scientists have studied the fossil record of related bird species from other parts of the world. By comparing the morphology and genetics of these fossils to living Galapagos finches, they have been able to infer the evolutionary relationships among these birds and their ancestors.
Taken together, these lines of evidence strongly support the idea that all 13 species of Galapagos finches are descended from a single common ancestor.