Without even realizing it, humans have become a dominant evolutionary force, driving rapid changes in countless species. The term “anthropogenic”—meaning caused by human activity—is commonly associated with climate change, but the scope of human impact goes far beyond. We are altering evolution at rates comparable only to the earth’s major extinction events.
In a recent study published in Philosophical Transactions: Biological Sciences, researchers Andrew P. Hendry, Kiyoko M. Gotanda, and Erik I. Svensson detail the wide-ranging ways humans impact evolution. Key factors include pollution, habitat fragmentation, urbanization, climate change, agriculture, hunting, invasive species, disease, and more. These forces often overlap, creating intense pressures on species worldwide.
One striking example of human-induced evolution is antibiotic resistance. The overuse of antibiotics has led pathogens to evolve super-resistance, challenging medicine worldwide. Similarly, the iconic case of the peppered moth during England’s Industrial Revolution illustrates how species can adapt to environmental changes: soot-darkened trees favored darker moths, which camouflaged better and avoided predators. When pollution lessened, the lighter form of the moth returned.
Other species have also adapted in response to human pressures. Killifish in heavily polluted waters have developed a tolerance to toxins that would kill most species. Populations of wolves, hyenas, and red squirrels are undergoing evolutionary shifts in response to unique stressors in their environments. Even elephants are evolving: some populations have fewer tusked females due to poaching pressures.
Hendry and colleagues note a distinction in how humans treat various species. We attempt to reduce “enemies,” like pests and pathogens, while fostering “friends,” such as crops and livestock. Some species are even considered “frenemies,” playing beneficial or harmful roles depending on circumstances. Meanwhile, many “neighbors,” neither beneficial nor harmful to us, are nonetheless driven to evolve by our multi-pronged impacts.
Our effect on the biosphere is profound: domesticated species like chickens, cattle, and pigs now vastly outnumber wild species. Our human-made structures and objects may even outweigh all living organisms on Earth. As our understanding of these impacts grows, so does our responsibility to guide evolution in safe and sustainable directions.
Welcome to Anthropogenic Earth—an era where humans hold extraordinary power over life’s future.
