All signs point to humanity beginning the process of colonizing other planets in the coming decades and centuries, and some scientists believe that in doing so, we may eventually create new branches of human evolution. Evolution is often determined by the environment in which the plant or animal involves, so it would make sense that putting humans in a new environment would put them on a different evolutionary path. Some even believe it will happen faster.
“These people will become an offshoot of the human tree, they will probably evolve into something else,” says Chris Impey, an astronomer at the University of Arizona. “They’ll evolve physiologically quite quickly because if the gravity is less — as it would be on Mars or the moon — then they will change. Their physical bodies will change even while they’re alive. And then if they have children and grandchildren — then they’ll change even more.”
You can find specific instances of this phenomenon all over the Earth too, just on a smaller scale. As humans and animals moved to different regions of the Earth, some of their physical attributes changed to better suit them to life in their new environment. This principle applies to space too.
“What we can say, though, is that new environments—for example, new radiation environments, whatever the gas composition is that people are breathing, whatever is the gravity field inside this starship,” says Cameron Smith, an anthropologist who agrees with Impey’s assessment. “Those basic environmental conditions will reshape the human genome. Subtly, subtly, but they will reshape it,” he continued.