from
https://www.inverse.com/article/55900-mars-city-near-sighted-offspring-could-find-sex-with-earth-humans-deadly
Near-Sighted Kids of Martian Colonists Could Find Sex With Earth-Humans
Deadly
Life on Mars will be an evolutionary roller coaster.
By Mike Brown on May 18, 2019
Filed Under Mars, 2050, Elon Musk, Evolution, Sex & SpaceX
Human
looking up at stars
It’s life, but not as we know it.”
The famous Star Trek refrain — actually a common misattribution — aptly
describes humanity’s future on Mars. And as more and more tech
entrepreneurs outline visions for how to erect settlements on the Red
Planet by the 2050s, Rice University professor Scott Solomon is already
starting to worry about what’s going to happen to the first Martian
settlers and, more interestingly, their babies.
“What’s interesting to me as an evolutionary biologist is thinking
about, what if we’re actually successful?” Solomon tells Inverse. “I
don’t think there has been nearly as much discussion about what would
become of the people that are living in these colonies generations later.”
Solomon’s 2016 book, Future Humans: Inside the Science of Our Continuing
Evolution, argues that evolution is still a force at play in modern
humans. In an awe-inspiring TEDx talk in January 2018 — which
inexplicably still has fewer than 1,000 views — Solomon outlined how
humans would change — literally — after spending a generation or two
living on Mars.
Far from waiting thousands of years to witness minuscule changes,
Solomon instead believes that humans going to Mars could be on the verge
of an evolutionary rollercoaster. He expects, among other things, that
their bones will be stronger, their sight shorter, and that they’ll, at
some point, have to stop having sex with Earth-humans.
“Evolution is faster or slower depending on how much of an advantage
there is to having a certain mutation,” Solomon says. “If a mutation
pops up for people living on Mars, and it gives them a 50-percent
survival advantage, that’s a huge advantage, right? And that means that
those individuals are going to be passing those genes on at a much
higher rate than they otherwise would have.”
Outside of Solomon’s field, discussion of this topic is relatively
sparse. Elon Musk’s SpaceX team is holed up in Florida and Texas working
on a stainless steel spaceship to send the first humans to Mars in the
2020s, establishing a city by 2050. Dubai has designed dramatic concepts
for its own Martian city, and the Matt Damon sci-fi flick The Martian
depicted how first trips to the Red Planet would take the form of
research missions.
These are all fascinating ideas, but they’re curiously short on how
humans may change under the treacherous, radioactive conditions of the
solar system’s fourth planet.
Mars
Human
Mars City: How Humans Could Change Over Time
Solomon outlined a number of ways — many of them covered in his Ted Talk
— about how humans could change.
Humans may develop denser bones to overcome the effects of Mars’
gravity, which is just a third of Earth’s. The reduced force could make
bones more brittle, which could lead to complications like fractured
pelvises during childbirth.
The inhabitants of smaller spaces may become more near-sighted, as they
no longer need to see as far as they would on Earth. Solomon cites
cavefish in deep trenches that have gone blind with no need for vision,
and studies that show children who spend more time indoors are likely to
become more near-sighted.
Mars inhabitants may develop a new skin tone to adjust to the higher
levels of radiation. Humans use melanin to fight against ultraviolet
rays, while other species use carotenoids. Mars residents may some day
have to develop another pigment entirely to fight off radiation.
Residents may perhaps learn to use oxygen more efficiently. A similar
change has been observed on the Tibetan plateau, where oxygen is 40
percent lower than it is at sea level. To adjust, Tibetans have denser
beds of capillaries to more efficiently move blood, and have the ability
to dilate their vessels to get more oxygen to the muscles.
One change that could occur relatively fast? Non-Earth dwelling humans
may quickly lose their immune system. In a sterile environment with no
microorganisms present, the residents may have no need for a body
capable of fighting germs. But this may not be such a bad thing, Solomon
suggests it could be an opportunity to eradicate diseases, treating the
ship flying to Mars as a sort of quarantine zone and ensuring the new
inhabitants can lead healthier lives.
It’s this latter change that may force humans to eventually splinter
irreversibly from their Earth-based counterparts. With no immune system,
sex between Martian humans and Earthlings would be lethal. That could
impose an artificial limit on how the two populations will be able to
interact and co-mingle. The inability to form families or send offspring
back and forth between the two planets could drive the two groups even
further apart, assuming the whole issue of “who pays who taxes” hasn’t
created an irreparable rift already.
Sparks around a campfire
Mars City: How This Human Takes Form
Solomon argues these changes will happen relatively quickly. Radiation
on Mars is extraordinarily high, he notes, without any sort of
magnetosphere to protect the humans. Children are normally born with
between 20 to 120 genetic mutations, but radiation could cause this
figure to spike and accelerate changes in genes.
Humans could also accelerate changes even more through gene editing.
CRISPR/Cas9 is a tool that could enable humans to ready our bodies for
Martian life more quickly, but with our current limited knowledge of the
human genome, random changes could have unexpected consequences. Still,
it could represent an avenue for alterations in the near future.
“Why wait around for this mutation to occur if you can just go in and
make them yourself?” Solomon says.
Another is the founder effect, which is the theory that gene traits of
the first inhabitants of a new area have a huge influence on the future
trajectory of the species. That means if we send up the most physically
capable humans to Mars, their offspring may be more genetically
predisposed to physical strength than humans on Mars.
It also means Musk and others will need to consider genetic diversity,
to ensure a good mix throughout the population. Solomon argues for
around 100,000 people migrating to Mars over the course of a few years,
with the majority from Africa, as that is where humans see the greatest
genetic diversity.
“If I were designing a human colony on Mars, I would want a population
that would be hundreds of thousands of people, with representatives of
every human population here on Earth,” Solomon says.
Hopefully the architects of these new worlds are listening.