Homo sapiens appeared on the scene about 300.000 years ago in Africa as the latest finds in Morocco confirmed. Still, there is much we don't know about our species. Many questions remained unanswered like who was our direct evolutionary ancestor. It is not yet clear whether humans evolved from Homo heidelbergensis or some other species. Homo heidelbergensis is an ancestor that we share with Neanderthals who are the closest relatives of present-day people.
Human evolution didn't follow a straight line with a succession of species, one replacing the other, but Homo sapiens may have co-existed with other Homo species until the only one species left - us, modern humans. Svante Pääbo, who decoded the Neanderthal genome and revolutionized our understanding of human evolution, has shown that Neanderthals and other extinct hominids have made a significant contribution to the ancestry of modern man. He and his team discovered genetic evidence of interbreeding between archaic and anatomically modern humans.
Scientists continue to fill in the gaps in human history by studying fossils and human and ape DNA.
What is the next step in the evolution of the 'wise man'? What comes after Homo sapiens?
Evolution
Our species never stopped evolving. In a recent massive genetic study, researchers have identified several single genes and gene sets that show how humans are evolving over one or two generations. Scientists are now able to observe ongoing selection in humans by identifying genetic variants that affect survival at a given age.
Genetic mutations are essential to evolution. Thousands of genes have evolved in the last 40,000 years. Eight percent of human genes have evolved as recently as 5,000 years ago. To illustrate, old Sumerians and Egyptians were different from us genetically.
Adaptation to environmental changes was the key driving force behind biological change in humans. All changes were powered mostly by natural selection. But thanks to technology and medical advances the number of ‘hazards’ we experience in our lives has drastically reduced. It disrupts the survival of the fittest concept because the weakest also live on and pass down their genes.
Future
There is a high probability that humans might take direct control over the evolution of their species and make it less 'natural'. In other words, we'll become intelligent designers of our species and start engineering superhumans.
Advances in genetic engineering have already opened up unimaginable possibilities. In the future, we might be able to make alterations to our immune system and life expectancy but also improve our intellectual capacities.
We might go even further and create cyborgs. Real-life cyborgs already exist! Neil Harbisson was born with achromatopsia. He is the world's first legally recognized cyborg with an antenna permanently implanted in his skull which gives him the ability to perceive colours as sound.
Jim Ewing is the first cyborg rock climber who lost his lower leg in a climbing accident. He has a brain-controlled bionic limb that enabled him to climb again.
Bionic limbs which operate through brain impulses have revolutionized prosthetics. It allows a person to control the movement of a prosthetic simply by thinking of commands. But in the future, technology might be used not just to overcome disabilities but to upgrade human abilities forming a symbiotic relationship between humans and machines. Technologies implanted inside us will obfuscate the distinction between humans and machines. Machines will not just help us do or think, they have the potential to help us be.
These predictions are very disturbing. The question is, how much of us can be symbiotically transformed while we are still considered human beings?
Predictions go even further.
Genetic engineering will lead to a new dominant species that some scientists call 'alien children' - designed babies born with the planned set of genes. The powerful gene-editing tool, CRISPR, is already employed to modify human embryos in vitro fertilization. CRISPR is a technique that allows scientists to make precise edits to any DNA by altering its sequence. So far, three 'CRISPR babes' have been born, all of them in China.
Despite calling for a global moratorium on human germline editing and changing the heritable DNA to make genetically modified children, it is impossible to control the use of CRISPR-Cas9 technology. It is inevitable that in the next 100 years, numerous embryos edited for desirable traits will be implanted and become children.
In a not-so-distant future, gene-editing technology could affect nature at an unprecedented level. I can't imagine a more nightmarish scenario than ill-intentioned people being able to redesign nature to meet their needs.
We don’t know for sure when Homo sapiens got on this planet but we know that more than 99 percent of all species that once existed no longer do. According to calculations, life on Earth has a maximum life expectancy of 7.5 billion years before the Sun expands and becomes a swollen star called a red giant. Humans are also very likely to disappear from this planet long before the Sun swallows the Earth.
J. Richard Gott III, a Princeton University astrophysicist, has predicted when humans will go extinct. He based predictions on the Copernican principle which states that humans, on the Earth or in the Solar System, are not privileged observers of the universe. Indeed, humans do not occupy a privileged place in the universe. Earth is not the center of our solar system, the Sun is not the center of our galaxy but one among billions of other stars, the Milky Way Galaxy is one among billions of other galaxies in the universe, and so on.
By applying a temporal version of the Copernican principle he developed a formula for predicting approximately how long something will last based on its present age: (1/39) tp < tf < 39 tp (P = 95% ), where tp = past longevity (how long something has already existed) and tf = future longevity. P = 95% is a scientific criterion that the prediction should have at least a 95 percent chance of being correct.
In short, the probability of a phenomenon’s future duration (tf) will be between 1/39 and 39 times its present age.
Applying the equation to the 'wise man' who has been around for about 300,000 years (200,000 in Gott's formula) the future duration of our species is between 1/39 and 39 times 300,000 years - or at least about 8000 years but less than 12 million years.
Believe it or not in the accuracy of the equation or believing it is all just good fun, the estimation is quite in line with those for other extinct species of hominids and mammals. Homo erectus lasted about 2 million years, while Neanderthals lasted 0.3 million years. One of the largest dinosaurs that ever lived, Tyrannosaurus rex lasted 2.5 million years.
Predicting the future of complex systems is difficult or even impossible, and so is the future of Homo sapiens.
Will Homo sapiens be replaced by 'Homo nouveau' as predicted by Don Simborg?
Will this new species be induced by genetic engineering, other technology, or a global catastrophe? Will we be the ones who create this new species? In effect, will Homo sapiens create Homo nouveau? Will two Homo species be coexisting?
We don't know the answers.
Maybe, as Copernicus stated, we are not significant species in the universe who lives in a special place, at a special time, but I can only say - what an amazing species we are and what an incredible journey Homo sapiens had hitherto.