# I don't understand this biology question.

I don't understand this diagram. How do I interpret it?
(edited 3 weeks ago)
Original post by BlackLives
I don't understand this diagram. How do I interpret it?
I want to preface this by saying that I am in GCSE and I think it is AQA A-level bio you are doing, so interpret my answer how you will. But just going off my interpretation:
I assume the further to the left the branch splits, the further back the migration was, so you need to compare when each split is that leads to a single strain. For example, the first split is on the bottom where it split to India N2 and two others. Since that is when there is a single split that leads to a single strain of India N2, that means India comes first. Next split that leads to one strain is the top branch which leads directly to Europe E1, so Europe comes second. Next split is on the bottom branch where it splits to India and East Asia, but since India was first, East Asia is the third. Next comes on the top branch, where it splits to Central America C1 and two others, so Central America is fouth. The last split is on the top branch splitting into South America S1 so South America comes last. By this we can see the order is India, Europe, East Asia, Central America, South America, which is option 3
Original post by zmp903
I want to preface this by saying that I am in GCSE and I think it is AQA A-level bio you are doing, so interpret my answer how you will. But just going off my interpretation:
I assume the further to the left the branch splits, the further back the migration was, so you need to compare when each split is that leads to a single strain. For example, the first split is on the bottom where it split to India N2 and two others. Since that is when there is a single split that leads to a single strain of India N2, that means India comes first. Next split that leads to one strain is the top branch which leads directly to Europe E1, so Europe comes second. Next split is on the bottom branch where it splits to India and East Asia, but since India was first, East Asia is the third. Next comes on the top branch, where it splits to Central America C1 and two others, so Central America is fouth. The last split is on the top branch splitting into South America S1 so South America comes last. By this we can see the order is India, Europe, East Asia, Central America, South America, which is option 3

I understand perfectly now. Thanks a lot.