This diagram is using the dynamic sign with arrow and sometimes the number and text help to explain. It shows the human journey from global DNA data which spread out from east Africa in 2000,000 ago to all of the world. And They aggregate tons of infographics from other sites, including National Geographic and The Economist.
But when I looked at this diagram first time, I didn’t understand what they are taking about honestly. There was just a little explain on the corner. And I also didn’t understand why they use the different colour to show different continent. The colour didn’t have any meaning, just used to divide continent. If the using different colours has a meaning connected with yeas, it would be better than just dividing it I thought.