Martian (All Tomorrows)

The Martians were the first extraterrestrial human species to evolve from Humanity.

Biology
Biologically, the Martians were similar to the humans of Earth, but hundreds of years in the lower gravity of Mars caused them to grow taller and thinner. They had become a distinct species with the help of genetic engineering.

Colonization of Mars
After the eventual political unification of the human race on Earth. Humans were finally able to colonize Mars. This was driven by the collapse of the environment by a population size of 12 billion people.

The plan was to create a breathable atmosphere first and foremost. Which was achieved by bombarding Mars with genetically tailored microbes. Those took centuries to turn the atmosphere of Mars into something that humans could breathe. Artificial oceans were then made for genetically modified versions of terrestrial flora and fauna for the inhabitants of the planet.

Mars was then colonized in one-way ships packed with colonists after which, several hundred years. Mars prospered though, never was economically advanced as Earth. Earth's businesses relocated their environmentally damaging industries to Mars. To overall strengthen Earth's tired biosphere and ecology prospered.

Mars-Earth Schism
The inhabitants of Mars began to develop their own, separate identity as Martians. This was not only a cultural difference, a biological one as well. A combination of genetic engineering and natural evolution altered the Martian's bodies to look spindly, an adaptation from the lower gravity on Mars. Over many generations of accelerated evolution, Martians became genetically distinct from terrestrial humans at this time.

Practically since its establishment, Martian culture was suffused with an explicit theme of rebellion against Earth. Songs, movies, and daily publications touted these notions again and again until they became internalized. Earth was the old, ossified home that held humankind back, while Mars was new; Dynamic, active, and inventive and to the Martian's thought to be the future of humanity.

Civil War
These rebellious thoughts fermented for a thousand years. Mars banned nearly all trade and travel to Earth with the exception of essential trade. This was a catastrophe for Earth both environmentally and economically, nobody wished the other to starve but the ban that was put in place caused the people of Earth roughly to lose a third of all yearly income.

Earth declared war on Mars in response. The war was fought by drones which were programmed to do as much damage as possible to the opposing planet. Phobos, a satellite of Mars, was destroyed and came down apon Mars as meteorites, while impacts on Earth killed a third of its population.

Aftermath
After the death of roughly eight billion people, Earth and Mars finally made peace then came together as a unified solar system. Both sides agreed that massive changes were necessary to secure peace between the planets and through genetic modification, the Star People were created as a new united humanity.

Appearances

 * All Tomorrows, by C. M. Koseman (2006)