Which of the following statements is supported by DNA studies of Darwin's finches?

• A. Darwin's finches evolved independently from unrelated bird species.
• B. Genetic differences among finch species are unrelated to their beak shapes.
• C. All species of Darwin's finches share a common ancestor.
• D. There is no evidence of gene flow between different finch species.

Answer: (C)

Verified step by step guidance

1. Understand the context: Darwin's finches are a group of bird species studied by Charles Darwin, which exhibit diverse beak shapes adapted to different ecological niches. DNA studies provide insights into their evolutionary relationships.
2. Step 1: Recall the concept of common ancestry. DNA studies can reveal genetic similarities among species, which indicate that they share a common ancestor. This is a key principle of evolutionary biology.
3. Step 2: Evaluate the first statement: 'Darwin's finches evolved independently from unrelated bird species.' This is unlikely because DNA studies show genetic similarities among finch species, supporting a shared evolutionary origin rather than independent evolution.
4. Step 3: Evaluate the second statement: 'Genetic differences among finch species are unrelated to their beak shapes.' This is incorrect because genetic differences, particularly in genes like BMP4, are directly linked to variations in beak morphology, as shown in studies of Darwin's finches.
5. Step 4: Evaluate the third statement: 'All species of Darwin's finches share a common ancestor.' This is supported by DNA evidence, which shows that all finch species are genetically related and descended from a single ancestral species.
6. Step 5: Evaluate the fourth statement: 'There is no evidence of gene flow between different finch species.' This is incorrect because DNA studies have shown evidence of gene flow (interbreeding) between some finch species, especially in overlapping habitats.