There used to be 9 human species, but now only we remain. But can humanity still evolve? For that to happen, isolated populations must endure distinct selective pressures.
Humans Will Continue to Grow Taller
Animals often evolve to larger sizes over time. This trend has been observed in Tyrannosaurus rex, whales, horses, and primates, including hominins.
Early hominins such as Australopithecus afarensis and Homo habilis were relatively small, standing between 120 to 150 cm tall. Later hominin species like Homo erectus (upright man), Neanderthals, and Homo sapiens (modern humans) are significantly taller. Humans have continued to increase in height throughout history, in part due to improved nutrition, but genes seem to be evolving as well.
Why humans are getting taller does not have a straightforward answer. In part, lower mortality rates could promote evolutionary changes in size; growth takes time, so living longer means having more time to develop. Additionally, women tend to prefer taller men. Therefore, both mortality rates and preferences for physical appearance are likely driving humans to evolve toward greater height. Today, the tallest populations in the world are found in Europe, with the Netherlands leading the way. Here, men average 183 cm and women 170 cm. One day, most people might be that tall or taller.
As humans grow taller, they also become more graceful, which seems paradoxical. Over the past 2 million years, the human skeleton has become lighter, relying less on brute strength and more on tools and weapons. As agriculture forced humans to settle down, lifestyles became less active, leading to decreased bone density. As we spend more time at desks with keyboards and steering wheels, these trends may continue.
Humans have also reduced muscle mass compared to other primates, particularly in the upper body. This trend is likely to continue. Our ancestors had to hunt antelopes and dig for roots; after that, they farmed and harvested in the fields. Nowadays, however, our jobs increasingly require more interaction, using words and codes rather than physical strength. This compels us to use our minds rather than our muscles. Even for manual laborers like farmers, fishermen, and craftsmen, machines like tractors, lifts, and engines assist them. As physical strength becomes less essential, human muscle mass will continue to decline.
Our jaws and teeth will also shrink. Early hominins that were herbivorous had large molars and jaws to grind tough plant material. As humans shifted to a meat-based diet and later began cooking their food, jaws and teeth gradually became smaller. Modern processed foods like fried chicken, french fries, and cookies even require less chewing, leading jaws to continue shrinking, and in future evolution, humans may lack wisdom teeth entirely.
Will Future Humans Be More Beautiful Than We Are Now?
After humans left Africa 100,000 years ago, distant tribes were isolated by deserts, oceans, mountains, glaciers, and what seemed like insurmountable distances. In many parts of the world, different selective pressures such as climate, lifestyle, and beauty standards have led to diverse human appearances. Ancient tribes developed distinctive traits in skin color, eye color, hair, and facial features.
With the rise of civilization and new technologies, these populations are becoming interconnected again. Wars of conquest, empire-building, colonization, and trade—including human trafficking—have altered and merged all populations. Today, roads, railways, and air travel connect people more closely. Indigenous peoples who once walked a few dozen kilometers to find another tribe can now fly thousands of kilometers in mere hours. We are increasingly becoming global citizens, freely moving within a flat world. This may lead to a future world of hybrids mixing African, European, Asian, Australian, and American traits from all five continents, with bright brown skin, dark hair, and varied complexions. It is plausible that the facial features of future generations will trend toward global neutrality.
Sexual selection will further accelerate the evolution of human appearance. With most forms of natural selection no longer at play, mate selection will play a larger role. Humans may become more attractive but more uniform in appearance. Global media may also create more uniform beauty standards, driving all humans toward a singular idea of beauty. However, gender differences may be exaggerated if the ideal human is envisioned as a masculine man and a feminine woman.
Will New Subspecies Emerge?
Evolutionary Tree of Humanity.
There used to be 9 species of Homo, but now only our species remains. But can humanity still evolve? For that to happen, isolated populations must endure distinct selective pressures. Geographic distance no longer creates isolation, but theoretically, reproductive isolation could be achieved through selective mating. If people are culturally separated, such as through religious, class, caste, or even political-based marriages, then distinct populations—perhaps even new species—could develop.
In The Time Machine, science fiction writer H.G. Wells envisioned a future where class creates separate species. The upper class evolves into beautiful but useless Eloi, while the working class becomes the ugly, diminutive Morlocks.
In the past, religion and lifestyle sometimes created genetically distinct groups, such as Jews and Romani people. Today, politics also divides humanity; could it lead to genetic divisions? Liberals now gravitate toward other liberals, while conservatives connect with other conservatives; many on the left would not date those on the right, and vice versa…
Could this divide humanity into multiple species? Probably not. However, within the scope of cultural divisions among humans, this could encourage evolution in different ways among different people. If cultures become more diverse, it could maintain and enhance the genetic diversity of humanity.
