Professor Tim Coulson describes evolution as a gradual process that alters living organisms over generations. The mechanism is ordinary but powerful. Small genetic mutations appear in DNA. Most do little or cause harm. A few improve survival or reproduction. Those traits are passed on more often and become common in a population. Over long periods, this steady sorting changes species. It explains why life on Earth looks the way it does today. From early single-celled organisms to complex animals, each form carries traces of earlier change. Humans are part of that same pattern. Evolution has not stopped. It continues quietly in every generation, shaped by environment, competition and chance events that no species fully controls.
From primates to octopuses, the race to replace humans explained
According to an interview published on The European, life on Earth has been evolving for about four billion years. Animals appeared roughly 600 million years ago. Modern humans arrived only around 300,000 years ago. In his book The Universal History of Us, Coulson follows that long chain of events from the Big Bang to the present. The argument is simple. Extinction is normal. Nearly every species that has existed has disappeared. Humans will not be the exception, even if that end lies far ahead.If humans vanished, landscapes would not remain empty. Forests, oceans and grasslands would shift. Species that survive would expand into spaces left behind. Some would adapt. Others would fail. The pattern would not be orderly. It rarely is.
Primates face limits despite intelligence
Chimpanzees and bonobos are often seen as possible successors because of their intelligence and social complexity. They use tools and cooperate in groups. Yet their populations are small and fragmented. They reproduce slowly and rely on stable forest habitats. In a scenario involving large-scale collapse, they could face the same pressures as humans. Intelligence alone may not be enough.
Birds and insects show structured societies
Certain birds, including crows and parrots, solve problems that once seemed uniquely human. Some insects construct vast colonies with clear organisation. These examples show that complex behaviour evolves in different ways. Still, physical constraints matter. Wings and small body size limit the kind of construction birds can manage. Insects operate largely through inherited behavioural patterns rather than flexible planning. Their societies are intricate but fixed in structure.
Octopuses combine intelligence and adaptability (Image Source – Canva)
Octopuses combine intelligence and adaptability
Coulson suggests octopuses as a more unusual candidate in discussions of post-human evolution. Octopuses manipulate objects with flexible arms and display advanced problem-solving skills. Their nervous systems are partly decentralised, allowing independent control of limbs. They adapt to varied marine environments, from shallow reefs to deep water.There are limits. Octopuses lack skeletons, which makes extended movement on land difficult. They are bound to water for now. Any major transition would require evolutionary change over vast periods. Even so, oceans cover most of the planet. Intelligence in marine settings may follow paths that look unfamiliar from a human viewpoint.