The Fourth Great Transformation

by Don Simborg

Introduction

If you’ve read the introduction on this website to my other book, What Comes After Homo Sapiens?, you would have seen the image above. It shows transformations. The figure to the far right is meant to depict a speculative future human species that I have named Homo nouveau. The figure just to the left of Homo nouveau represents us, Homo sapiens. The four other figures to the left of Homo sapiens are unnamed creatures meant to represent an evolutionary transformation from something apelike to something more like us. Perhaps if I were to name them, they could be Chimpanzee, Ardipithecus, Australopithecus and Homo erectus. Or someone else might name them Bonobo, Sehelanthropus, Kenyanthropus, and Homo heidelbergensis…or some other combination of Latin-sounding names given to fossils found mostly in Africa.

We don’t know for sure what the exact path was to Homo sapiens, but we do know that these transformations from an apelike creature occurred over the past 7 million years. Although the figure depicts only four transformations, in reality there were hundreds or even thousands of them, depending on how you define a transformation. Some were more important than others. In fact, I would lump all of these transformations between ape and human as one Great Transformation which culminated in the emergence of the human brain in Homo sapiens. Thus, in my terminology, this figure depicts only a single Great Transformation.

In this book I consider the emergence of the human brain as The Third Great Transformation in the total history of evolution. So what were the first two? They are not shown in this figure and would appear far to the left if I had to draw some representation of them.

Earth itself is about 4.5 billion years old. After some time to cool down a bit, the first evidence of life appeared on Earth about 3.8 billion years ago. As far as we know, those earliest life forms were single-celled organisms similar to the ubiquitous bacteria alive today. Although they remain the simplest forms of life (note that viruses are not considered to be “alive” by most biologists), they are actually quite complex organisms. They can wall themselves off from the rest of their environment, metabolize external sources of food for energy, move around, replicate and evolve over generations. That’s quite a list of capabilities for bacteria to be considered alive, and it seems amazing that they all actually happened roughly at the same time way back then. We don’t know how that happened, or even if that happened initially on Earth rather than arriving here on some flying rock or ice from elsewhere. I have designated this mystery of the emergence of life The First Great Transformation in evolution.

There were actually two types of those earliest single-celled organisms: bacteria and archaea. Archaea differ from bacteria mainly in the types of cell walls they have, but basically are otherwise very similar. Archaea tend to like more extreme environments than bacteria, but they are everywhere including in our digestive tracts. Bacteria and archaea coexisted on Earth as the only organisms for about 2 billion years. Then something amazing happened. Somehow, one species of archaea engulfed a species of bacteria and the bacteria remained as a living component of the archaea for the rest of evolution. That living component is a part of every plant and animal cell today and is known as mitochondria. Mitochondria are the energy producers for all of our cells. We couldn’t live without them. And since they are remnants of bacteria, they still contain some of the former bacterial DNA. Thus, a small number of our genes—37 to be exact—are housed in our mitochondria. Our other 20,000+ genes are in our cell nuclei. And that brings me to the other amazing thing that happened 1.8 billion years ago when the archaea engulfed the bacteria. All of the archaea DNA which contained their genes became enclosed in an internal cell wall within each cell to create a nucleus. Archaea and bacteria have neither nuclei nor mitochondria. Together, these two features of cells emerged at roughly the same time to create a totally new type of cell: the eukaryote. That amazing combination of events to create the eukaryote cell is what I designate as The Second Great Transformation in evolution. What is so special about the eukaryote cell? It enabled the evolution of all plants and animals, including us. All plants and animals are multi-cellular organisms rather than single-celled. Multi-cellular organisms have different types of cells working together, like heart cells and brain cells. It is the eukaryote cell that enables this specialization and cooperation.

Thus we have had a total of three Great Transformations in the history of our evolution—each successive one dependent on the previous. First we had the emergence of life. Then, after two billion years, the eukaryote cell emerged leading to all plants and animals, including us. Finally after another 1.8 billion years the human brain grew to its current size and complexity, becoming the most complex organic structure in the known universe. It will take us decades or even centuries to fully understand how the brain does what it does.

It is because of this brain that I am hypothesizing that we are on the cusp of The Fourth Great Transformation—the creation of the next human species using the tools created by the human brain.