The story of humanity is a story of adaptation. Over the past 200,000 years, ever since the first modern humans (Homo sapiens) appeared in Africa, people have been spreading outward from that continent in every possible direction. As they encountered new environments and challenges, our ancestors had to change in many ways to survive.

New dangers meant that only the physically strongest or smartest humans tended to live long enough to pass on their genes.

According to the paper Physiological and Genetic Adaptations to Diving in Sea Nomads, published in April 2018, the Bajau (sea nomad) people of Southeast Asia are a modern example of evolution-in-action. Their subsistence lifestyle is based around diving to depths of 200 feet or more underwater to harvest fish and shellfish. They live in stilt-huts along coastal waters, hundreds of thousands of them in fairly isolated communities in Malaysia, the Philippines and Indonesia.

The researchers discovered numerous physical differences between the Bajau people and indigenous folk who live inland.

Using a comparative genomic study, we show that natural selection on genetic variants in the PDE10A gene have increased spleen size in the Bajau, providing them with a larger reservoir of oxygenated red blood cells. We also find evidence of strong selection specific to the Bajau on BDKRB2, a gene affecting the human diving reflex.

This is among the most recent evidence that human populations on Earth are still evolving.

In the paper titled Human High-Altitude Adaptation: Forward Genetics Meets the HIF Pathway, the authors write, regarding populations of people who live in the high altitude regions of the Tibetan Plateau, the Andean Altiplano, and the Semien Plateau of Ethiopia:

Intriguingly, genetic signatures in genes of the hypoxia-inducible factor (HIF) pathway, the central pathway that transduces changes in oxygen tension to changes in gene expression, have been identified (Kaelin and Ratcliffe 2008; Lendahl et al. 2009; Majmundar et al. 2010; Semenza 2012). This suggests that in indigenous high-altitude populations, selection for adaptation to chronic hypoxia (as opposed to cold, increased UV irradiation, or some other environmental stress experienced at high altitude) is a key component of their recent human evolution.

Homo futurae

Even as small, isolated populations still continue to evolve on their own, the majority of Earth’s population is experiencing something of an opposite effect. The expanded ability of most people to communicate with one another and move across borders and oceans has been leading to an unprecedented intermixing among our species over the past 100+ years.

Right now, most of humanity can be grouped into specific genetic clusters of people most closely related to one another:

These populations evolved over time as people emigrated from place to place in search of new resources. The following map displays genetic groups as a factor of what general region they originated from:

The evolution on display in our modern world is actually of two types: Evolution caused by specialization in isolated populations, and evolution driven by selective breeding. The second type is what will determine humanity’s near-future course.

By “selective breeding”, I refer strictly to the power that social stratification has upon society. Though at this point it has been proven that genetic traits do not determine a person’s class standing, something of an opposite effect is happening due to the continually growing gap between rich and poor. Just as throughout all of history, people in the highest status of a society tend to mate and produce offspring, while those of lower status mate within their class. While in the past the wealthiest classes tended to be quite small and isolated, in our modern world the sheer numbers of the wealthy classes are much larger (though the overall % remains rather small), and they are much more mobile.

This is a rather recent phenomenon, occurring mainly since ~1900, but the results are already visible: The rich already display genetic tendencies greater than the general population toward slightly higher fitness potential and physical attractiveness. This is caused by our modern culture which values these traits to such a degree that people who reach the peak of careers reliant on such traits are rewarded handsomely, propelled into the upper class. While many of the upper classes are born into their status and remain there due to inheritance — which was, until the 20th century, the only real way to get there — that same portion of society is now mixing with a new group of “genetically superior” celebrity-class individuals.

This genetic class stratification will be further compounded within this century by the wealthy’s ability to afford medical procedures that ensure, and even allow choice of, their offspring’s traits: the upcoming trend of “designer babies”. Soon, the children of the wealthy will be born with a base level of physical fitness, attractiveness and intelligence that automatically places them in the top 1% of the human race.

Further out, in the 10–100 thousand year range from now, the processes that drive human evolution will come full circle, in a way, as our species once again splits into innumerable different groups during our time of colonizing the Solar System and exoplanets of other nearby stars. Living on worlds with significantly higher or lower gravitational pull than Earth will eventually transform the standard human body, as will the varied atmospheres, pressures, and exposure to different degrees of cosmic and solar radiation.

In one million years, Home sapiens sapiens, the modern subspecies of Home sapiens to which we all belong, will no longer exist as such. There may be new subspecies living on worlds separated by tens of millions of miles and even light years: Homo sapiens Martis, Homo sapiens Titanus, Homo sapiens Centaurium, etc. Or perhaps these will be completely new species by that point, unable to interbreed.

The evolution has just begun…

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