Outline5 marksStandard
A population of a butterfly species (Erebia tyndarus) originally lived in a continuous alpine meadow. Over millions of years, tectonic uplift created a mountain range that split the habitat into two separate valleys (Valley A and Valley B). The butterflies in each valley are now morphologically distinct and cannot interbreed when brought together. Researchers have compared DNA sequences of several genes from the two populations and from other related species.
Outline how the formation of the mountain range could lead to allopatric speciation, and explain how DNA sequence data can provide evidence for this process.