In this blog post, we’ll examine how scientific advancement affects human evolution and consider the implications of technological progress for human adaptation and evolution.
Living organisms are generally sensitive to temperature and their environment. For many plants and animals, their habitable range is limited by various environmental conditions, such as temperature and humidity. However, thanks to these characteristics, each species has adapted and evolved to suit its specific environment. For example, even among foxes, the Arctic fox, adapted to cold environments, and the desert fox, adapted to hot environments, demonstrate how they have evolved to suit their respective environments. In this way, diverse plants and animals have fostered intraspecific diversity by adapting to their local environments. In contrast, while there are physical differences between the Inuit living in Alaska and northern Canada and the indigenous peoples of Africa living near the equator, these differences are not fundamental enough to classify them as separate species. Of course, skin color, certain physiological characteristics, and lifestyles have varied as a result of adapting to their respective environments. I believe these differences are related to the development of human science and technology, and I think it is necessary to consider whether scientific progress might be stalling human evolution.
First, when discussing evolution, Darwin’s theory of evolution is indispensable. Before the emergence of Darwin’s theory, understanding of biological evolution was limited, and a hierarchical view of life—which regarded humans as the most advanced organisms—was widely accepted. However, in 1859, Charles Darwin published ‘On the Origin of Species’, and after much debate, it became a crucial starting point for modern evolutionary biology. Of course, modern evolutionary biology has advanced further based on a contemporary synthetic theory that integrates genetics, molecular biology, and population genetics, but natural selection is still recognized as a core principle. Natural selection refers to the process by which individuals in a population possessing traits advantageous in their environment achieve higher survival and reproductive success, thereby passing those traits on to the next generation. Representative examples include the giraffe’s long neck and the diverse beak shapes of the Galápagos finches. In this way, plants and animals have evolved as individuals with more advantageous traits are selected to survive in their given environments.
Humans, too, have adapted and evolved through natural selection. One of the most notable examples is the spread of the ability to digest lactose, known as lactase persistence. As humans began raising livestock and consuming milk on a regular basis, the genetic trait enabling the digestion of lactose even in adulthood became more prevalent in certain populations through natural selection. Even today, there are significant regional differences in the ability to digest lactose, but in some areas where pastoral cultures have developed, this trait is found at a high rate. However, with the advancement of science and technology today, humans are living in a way that involves changing or overcoming the environment itself rather than adapting to it. For example, when temperatures rise and ultraviolet radiation intensifies due to climate change, humans lower indoor temperatures with air conditioning or protect their skin by using sunscreen. In contrast, among most plants and animals, individuals with diverse traits emerge to adapt to changing environments, and those best suited to the environment survive and pass their traits on to the next generation. From this perspective, science and technology have greatly reduced the need for humans to adapt directly to environmental changes, and as technology continues to advance, the process by which the body adapts to environmental changes is likely to become a less significant factor than in the past. I believe it is worth considering whether these changes might partially reduce the opportunities for natural selection to operate within human populations.
If so, what is the relationship between individual diversity and evolution? American evolutionary biologist Stephen Jay Gould explained that the direction of evolution is not simple progress but rather the expansion of biological diversity. He argued that the emergence of complex organisms was not an inevitable progression but rather the result of chance and natural selection. In contrast, British evolutionary biologist Richard Dawkins interpreted the process of increasing fitness through natural selection from the perspective of progress. Although the two scholars’ perspectives differ, the fact that the greater the variety of traits within a single species, the greater the likelihood that individuals capable of adapting to environmental changes will emerge, holds significant meaning in evolutionary biology. Therefore, individual diversity can play a positive role in enhancing a species’ ability to respond to environmental changes. Conversely, if opportunities for diverse traits to emerge decrease, the scope for natural selection to act may also diminish in the long term.
The relationship between individual diversity and evolution can also be observed in the evolutionary history of humankind. Over the course of approximately 7 million years of evolution, there were periods when multiple human lineages coexisted, rather than just a single human lineage. Among these, the most widely known group is the Neanderthals. Although Neanderthals coexisted with modern humans for a long time, most of them disappeared about 40,000 years ago. Various hypotheses have been proposed to explain this, including climate change, competition, and the genetic vulnerability of small populations; it cannot be attributed to a single cause. Furthermore, while it was once believed that modern humans completely replaced Neanderthals, genomic research now shows that, on average, modern humans outside Africa retain approximately 1–2% Neanderthal DNA. Meanwhile, a study published in 2016 suggested that the Neanderthal Y chromosome differed from that of modern humans, and that these differences may have been related to reproductive fitness. As such, human evolution has also taken place through the interaction of various populations and diverse genetic traits.
In the past, when science and technology were not yet advanced, humans—like other plants and animals—survived by adapting to changing environments. Natural selection has consistently acted upon humans as well, and among various genetic traits, those advantageous to the environment have been passed down to subsequent generations. However, modern science and technology are enabling humans to significantly reduce the influence of the natural environment. As a result, the extent to which natural selection operates in the same way as in the past may have decreased to some degree. Of course, research findings also suggest that human evolution continues today, influenced by various factors such as infectious diseases, living environments, dietary habits, and patterns of childbirth. Therefore, it is difficult to conclude definitively that science and technology have completely halted human evolution. However, it is clear that science and technology are significantly altering the very way humans adapt to their environment. I believe that, amid these changes, the future direction of human evolution remains an important topic that requires ongoing research and consideration.
