What would happen in your world if all people were equal if there were no diversity?
There would be just one type of music which you would listen to, the same as everyone else; and you wouldn’t be able to discover new singers, bands or styles of music that you could identify with. You would dress like everyone else and have the same haircut. You would not be able to have your own style or be unique. There would be just one sport, and everyone would practice it and watch it on TV.
When new challenges arise in society, there would be no original ideas or unique thoughts that would allow for ingenious new solutions.
There would be no bacteria, plants, and animals, but only organisms with a single form and function since they would all have the same DNA.
And in nature, what would happen if there were no variation?
Just like in your world, nature also needs variability. Just as variations in music sometimes give rise to new musical styles, variations in DNA sometimes give rise to new organisms.
Within a group of organisms, changes in their DNA sometimes make them more able to adapt to changes in the environment. For example, the changes in DNA that are responsible for the different skin colors in humans made us better adapted to one environment or another.
Did you know that the first humans emerged in Africa and had dark skin?
Humans left Africa and began to explore other continents, first Asia, then Oceania and Europe, and finally America. On these continents, the different environmental conditions made survival a challenge. For example, the amount of sunlight received across these continents is different. When it is very sunny, we need our skin to be able to protect us from ultraviolet radiation, but we also need a little light in order to produce vitamin D, which is essential for growth. After leaving Africa and settling in less sunny places, people with slightly lighter skin survived better due to some genetic change they carried. As they survived more, they were able to pass this change on to their children, and thus, over the generations, the skin color of the population became lighter.
Skin color varies continuously, which means we can establish a continuous gradient from very dark to very light skin. People who live in the tropics have darker skin compared to people who live in temperate climates, and vice versa. Now, current knowledge allows us to survive regardless of skin color: dark-skinned people who live in places with little sun can take vitamin D supplements, and light-skinned people who live in sunny places protect themselves with sunscreen.
This road movie will take you across three continents in search of the origin of humans.