Which mountain range was formed first (historically) and which the pedigree is correct? Source 1: !enter image description here Source 1 shows a map of a particular area. In this map you will find the mountain ranges 1 and 2, the species P, Q and R. Two possible pedigrees of the ancestral history of the species P, Q and R are drawn . Which mountain range was formed first (historically) and which pedigree is correct?

If mountain range `1` was formed first, pedigree `1` is correct.

If mountain range `2` was formed first, none of the two pedigree seem correct.

If mountain range `1` was formed first you would first have the split of the initial population into population `P` and the population `Q+R`. Then, the formation of mountain range `2` split the population `Q+R` into `Q` and `R`. Therefore, `Q` and `R` are more closely related than they both are to `P`. Therefore Pedigree `1` is correct.

You can apply the same kind of reasoning by guessing that mountain range `2` was formed first and you will realize that you would expect a pedigree different than Pedigree `1` and Pedigree `2`. If mountain range `2` appeared first then, the correct Pedigree would display the population/species/lineages `P` and `Q` more closely related to each other than they both are to `R`.