From his study of Galapagos finches, Darwin derived his theory of evolution from

1. Analyze the question The question asks which line of evidence Darwin used in forming his theory of evolution from the Galapagos finches.

2. Explain the concept Darwin visited the Galapagos Islands during his voyage on HMS Beagle. He noticed that the finches on different islands looked very similar overall but differed in beak shape and size. Each beak was suited to the food available on its island (seeds, insects, buds and so on).

Comparing the structures (beaks, body form) of related organisms is called comparative anatomy. Similar basic structures with modifications for different functions point to descent from a common ancestor. This is known as adaptive radiation.

3. Solution, step by step

• Option B, comparative physiology: Darwin did not compare body functions among the finches. He compared their physical structures. ✗
• Option C, fossil remains: the finches were living birds, so the observation was not based on fossils. ✗
• Option D, comparative embryology: this compares embryo development, which was not what he studied in the finches. ✗
• Option A, comparative anatomy: he compared the beak structures and body forms of the different finch species. ✓

4. Answer The correct option is A. comparative anatomy.

5. Exam tip Link the keywords with the evidence:

• Galapagos finches, beaks, limbs → comparative anatomy (homologous structures)
• Fossils, Archaeopteryx → palaeontology
• Embryos with gill slits → comparative embryology

Also remember that Darwin's mechanism was natural selection, and the finches are the classic example of adaptive radiation.