The Third Flowering of the Tree of Life

by Jonathan Loh

Jonathan Loh (British, born 1963) is a zoologist specializing in the monitoring and conservation of biological and cultural diversity. He is an honorary research associate at the Zoological Society of London and consultant to WWF International.

Within the next forty years an event will take place that will alter not just the history of our species but the evolution of life itself. We may not know when exactly it occurs, but by 2052 we will be fully aware that it has happened. Such events have occurred twice before, but in different ways, and the third time will be different again.

To describe these past events, and the one to come, I will employ the analogy of the Tree of Life. This tree sporadically, suddenly, and spectacularly flowers15 from one of its outer branches. It has done so twice, the last time at the tip of one of its myriad outer twigs.

The first flowering was the start of the evolution of all multicellular organisms 550 million years ago, and the second marked the beginning of human cultural diversity some 70,000 to 80,000 years ago. A third flowering is about to begin on the outer edge of the tree, leading to a new evolutionary diversification.

Imagine the history of Earth condensed into a single year. The planet coalesced from hot dust and gases in the solar disk around 4.5 billion years ago; let us call this time 00:00 hours on January 1. Then it began to cool. Life first appeared sometime in March, but until November all living organisms were unicellular. Around mid-November single cells began grouping together into the first multicellular life forms, known as the Ediacaran fauna.

The First Flowering

The Ediacarans lasted only days before being blown away on November 18 by the Cambrian explosion: a sudden burst of evolutionary activity producing new life-forms at a rate unrepeated before or since. Bizarre organisms of enormous complexity appeared. Many had hard body armor and possessed formidable weaponry. The evolutionary arms race had begun. By the morning of November 20 it was all over. The first flowering had ended, but all organisms have since conformed to the basic blueprints that evolved at that time.

The Tree of Life continued to branch and grow, producing new species and losing old ones, for more than half a billion years. Then an extraordinary, unparalleled event occurred at the end of one of its branches in the late evening of December 31. That particular outer twig—one of millions—did not look exceptional, for although it represented a large mammalian species, it was by no means the biggest, or fastest, or the one with the most impressive body armor or weapons. But it began to talk. The species on that twig was our own, and as a result of our remarkable and unique innovation, language, the tree started its second exuberant flowering.

The Second Flowering

Modern humans first appeared around 200,000 years ago, well into the final hour of our year. Just how or when human language evolved is not known. It may have started with gestures rather than vocalizations. But once it had taken hold it enabled an entirely new mode of evolution—cultural evolution. Cultures evolve in a manner similar to species, through variation by mutation, hereditary transmission, and selection. The transmission of culture is mediated not through the passing of DNA from parent to offspring, but through the learning of behavior by one individual from another. The transmission rate is greatly facilitated by language.
About 7,000 languages are spoken in the world today, and each can be considered the expression of a different culture. These languages represent the outermost twigs of the cultural tree, but there are many more extinct languages whose branches ended before the present. Like species, some languages can be classified into families sharing a common ancestor, while others stand alone.

A big difference between biological and cultural evolution is speed. Biological evolution is slow, while cultural evolution is so rapid it can be observed within a lifetime. Another difference is that borrowing occurs between languages. Borrowing words is the equivalent of different species exchanging genetic material, something most organisms cannot do.

Although the date of the origin of language is not known, it was almost certainly some 70,000 to 80,000 years ago. The population at that time was about 100,000 individuals, largely confined to the African continent. At this time, in the middle of the last ice age, or around 23:52 on December 31, people began to migrate out of Africa, gradually spreading across Asia, following coastlines and moving up river valleys. Their descendants succeeded in crossing the straits between mainland Southeast Asia and Australia some 40,000 to 60,000 years ago. Others moved north into Europe or over the land-bridge into the Americas. The last great migration crossed not land but the Pacific Ocean, finally reaching New Zealand only 1,000 years ago, or seven seconds to midnight.

As they spread across the globe, living in small isolated groups, the migrants carried their languages and cultures with them. Cultural evolution gave rise to thousands of local variations, leading ultimately to the vast diversity of human languages and cultures. This was the second flowering of the Tree of Life, the cultural explosion.


Diversification has always been accompanied by extinction. There have been at least five mass extinctions in which global species diversity was suddenly reduced, on November 26 and December 2, 12, 15, and 26. On December 12, 245 million years ago, 96% of species went extinct.

And on December 26, 65 million years ago, the last great extinction marked the demise of the dinosaurs. After each mass extinction, however, biodiversity recovered or exceeded its previous maximum.

Today, we stand on the brink of a sixth mass extinction. But this time we are losing cultural as well as biological diversity. Half of the world’s population speaks one of about 25 languages. Of the remaining 7,000 languages, about half are spoken by fewer than 10,000 speakers.

Languages go extinct because the speakers either die out or, more usually, shift to a second language and within very few generations forget their mother tongue. And with their language, their culture declines. The root causes are globalization, migration, modern communications, or sometimes coercion.

It seems unlikely that bio-cultural diversity loss will reverse before 2052. And yet, as bio-cultural diversity declines, I believe that another rapid diversification will erupt from one linguistic twig at the edge of the Tree of Life. The language will not be English or Chinese, but a very recent, invented one. A computer language will initiate the third flowering.

The Third Flowering

This will not be a computer language used by programmers to write software. This will be a language used by computers to write their own programs. The programs will be written using the same evolutionary algorithm that led to biological and cultural diversity.

The underlying principle is that a computer can be given an objective and an initial program to work on. The computer then copies the program many times over, introducing random changes to the code. It runs the new generation of programs, selects the one that works best, and discards the rest. The cycle is repeated, again and again, until it produces a program that satisfactorily meets the objective. Of course, in biological or cultural evolution, there is no ultimate objective; nor will there be in digital evolution. The selection of programs will be determined by the prevailing market for applications.

Being more efficient, computer-written programs will begin to displace human-written programs, and then computer-designed computers will replace human-designed computers. Eventually, humans will not fully understand how computers work. By 2052, computers will have evolved artificial intelligence and even consciousness.

Initially computers will depend on humans to manufacture them and feed them electricity, but this can increasingly be done by computers.

Most humans will welcome this evolutionary burgeoning of computer technology, as it will provide extraordinary new applications that make their lives easier or richer.

The rapid diversification of computer-written programs will have begun but not matured by 2052. The new branches of the Tree of Life will consist of populations of programs, just as the older branches comprise populations of species or languages, but their form or function is not yet clear. Human culture is transmitted via memes: ideas that can be copied from one individual to another. A meme is the cultural analogue of a gene, but inhabiting minds rather than cells. Computer cultures will exist outside of human minds, transmitted from computer to computer. I suggest that the basic unit of transmission be called an exeme, an executable meme, the digital analogue of a meme or gene.

So we face a future in which the two ancient forms of evolutionary diversity diminish while a new one rises. It is not a path we consciously planned or wanted, any more than our hominin ancestors chose to speak, or our unicellular ancestors chose to form multicellular species.

It will happen simply because a fundamentally new innovation allows massive evolutionary diversification. Where does it leave us? Will we be in control of computer culture? Or will computers come to view humans in the same way we view other species: interesting, useful, even necessary, but essentially a lower life-form?