I had thought you were arguing for strong selection pressure based on variation in pigmentation among aboriginal Australians compared to their latitude within Australia. The map doesn’t support that (in Australia or South America), since it has nothing to do with skin color.
If instead you’re arguing for pressure based on aboriginal Australians quickly becoming darker-skinned than their southeast Asian ancestors, then that doesn’t point to the importance of vitamin D. It points to the importance of not getting skin cancer. Rapid evolution of lighter skin would point to the importance of vitamin D. I suppose if the southeast Asian ancestors of aboriginal Australians had similar pigmentation to modern aboriginal Australians (maybe due to rapid migration from Africa? I don’t know), and if those who remained in southeast Asia developer lighter skin in that time, then that argument could work. But do we know what sort of skin tone the Asian ancestors of aboriginal Australians had?
As I said I don’t think Australian’s are the best example and South American’s are better.
I do agree that the image is misleading and I will look into updating the argument. I still believe that the thesis that evolutionary pressure lead people to develop dark skin while living near the equator in America is true, but it needs more sources.
I had thought you were arguing for strong selection pressure based on variation in pigmentation among aboriginal Australians compared to their latitude within Australia. The map doesn’t support that (in Australia or South America), since it has nothing to do with skin color.
If instead you’re arguing for pressure based on aboriginal Australians quickly becoming darker-skinned than their southeast Asian ancestors, then that doesn’t point to the importance of vitamin D. It points to the importance of not getting skin cancer. Rapid evolution of lighter skin would point to the importance of vitamin D. I suppose if the southeast Asian ancestors of aboriginal Australians had similar pigmentation to modern aboriginal Australians (maybe due to rapid migration from Africa? I don’t know), and if those who remained in southeast Asia developer lighter skin in that time, then that argument could work. But do we know what sort of skin tone the Asian ancestors of aboriginal Australians had?
As I said I don’t think Australian’s are the best example and South American’s are better.
I do agree that the image is misleading and I will look into updating the argument. I still believe that the thesis that evolutionary pressure lead people to develop dark skin while living near the equator in America is true, but it needs more sources.