Let assume the future has come, and mankind has managed to populate Mars and get comfortable there. What would Martian colonists look like after thousands of years? Would his appearance be different from that of an earthling?
Scientists say that prolonged residence on the Red Planet, where gravity and sunlight are weaker than on Earth, and radiation is much stronger, will lead to rapid evolutionary changes. Experts believe that Martians can turn into a new kind.
“Two populations of the same species settled in different isolated territories, begin to differ from each other – remember the Galapagos finches studied by Charles Darwin. The finches living on one island are different from the finches on the other island: in different territories, they have signs that help them survive in the very environment where they settled, Biologist Scott Solomon writes in his book “Future Humans: Inside the Science of Our Continuing Evolution.” It is written there as follows: “If speciation on Earth’s islands takes thousands of years, then on Mars, this process will go much faster due to the huge difference in conditions. In just 100-200 generations or 6000 years, a new kind of man may appear on the Red Planet.”
The new kind?
Six thousand years is a short time for a person to change beyond recognition. Modern Homo sapiens exists as a separate species for 160,000 – 45,000 years.
Biologist Philipp Mitteroecker of the University of Vienna in Austria says:
“Speciation is a lengthy process that usually requires reproductive isolation. Some human groups have been isolated for thousands of years and are still far from becoming a separate species. Therefore, it is unlikely that the people who colonize Mars will last for 6,000 years. On the other hand, conditions on the Red Planet are suitable for minor physical changes to begin appearing among the colonists after a hundred generations.”
For Mars, to undergo any evolutionary changes:
1) natural selection should work;
2) the local habitat must be different from the terrestrial. If you create completely terrestrial conditions on the Red Planet, strengthen gravity, put artificial lighting, produce the same food as, on Earth, people will not change;
3) differences in conditions should not be too strong so that the population does not die in the first weeks.
How Martians will differ from earthlings?
When a person settles on the Red Planet, he/she will no longer need a heavy, well-mineralized skeleton. The gravitation force on Mars is much weaker than on the Earth, the colonist’s weight there will be almost 3 times less, which means that the force on the skeleton is lower. The need for massive bones will disappear, the body will become unprofitable to spend energy on their content.
People with heavy bones will spend more calories, energy, and minerals to build their skeleton, so on Mars, they will lose evolutionarily to people with thin bones.
The same goes for the digestive tract. In conditions of reduced gravity, a person needs less energy for walking and physical labor, so he will not consume as much food as on Earth. The digestive apparatus will contract, the bodies of the colonists will become narrow.
When the Martian colonist arrives on Earth, people will see a thin man with fragile bones. The weight of a Martian will increase almost 3 times: a 38-kilogram individual on our planet will weigh 100 kilograms, this will cause an additional load on his bones. Most likely, he will not be able to move around without help, he will need a stick or a wheelchair.
A Martian visiting Earth will die after some time from heart failure.
On the Red Planet, in conditions of low gravity, the heart muscle does not need to work so hard and contract quickly to pump blood through the circulatory system, as on Earth. Therefore, the Martian’s heart will become weaker, that is, less trained. In terrestrial conditions, it simply cannot cope with the load.
Mars is much farther from the Sun than Earth. The red planet receives 1.5-2 times less light, because of this the eyes of the colonists can change.
“A sunny day on Mars is like a cloudy day on Earth, – explains Natalie Cabrol, a planetologist at SETI. – Our eyes are accustomed to a certain amount of light. Martians will have to adapt to new conditions: either the brain will develop a new method that allows the retina to perceive and process more light, or overtime, the colonists’ eyes will become larger.”
There is not much sunlight on the Red Planet, but the ultraviolet radiation (UV) subtle Martian atmosphere transmits many times more than Earth.
On our planet, for UV protection, the skin produces the pigment melanin, or rather, its variety – eumelanin, which acts as a natural sunscreen and gives the skin a brown tint. The more eumelanin in the skin, the better the ultraviolet rays are absorbed, and the darker the skin color becomes.
In his book, Solomon writes that people who have more eumelanin will be better able to withstand extreme ultraviolet radiation on the Red Planet. Therefore, the skin of the Martians will be much darker than anyone on Earth.
In the crowd, an earthman will easily notice a Martian. A guest from another planet will be distinguished by very dark skin, a narrow body, large eyes, and will move on a wheelchair.
Most likely, we would see a Martian dressed in a protective suit since direct contact with the earth’s environment for him/her could end in disrepair.
So far, scientists believe that there is no microbial life on Mars – pathogenic bacteria and other “creatures harmful to the body.” Therefore, the immune system of the colonists will cease to work in the form in which it works for us – it will lose the ability to fight earthly infections. Not to die, the Martian on Earth should never take off his protective suit and eat only sterilized food.
All the information cited in the article is a hypothesis based on the tenets of evolutionary biology. It is impossible to know exactly what adjustments nature will make in the appearance and organism of Martians.
If the colonists change a lot and differ from earthlings, what will we consider them? Aliens, or just another species? The time will show us.