IT has been estimated that 99.9 per cent of all species on our planet died out. One of the things that Charles Darwin said about human beings or Homo sapiens is that we are very much part of the natural world. This means that like all other species on the planet, Homo sapiens will one day also die out. At some point, our population will reach its peak and from there onwards, it will begin to fall. It just so happens that all those reading this article happen to be alive at a moment when humans may be about to reach their maximum numbers.

According to UN population estimates, humans will reach their maximum population in 2086 at 10.4 billion humans. This number, large as it is, is still lower than what scientists had predicted earlier. Talk of the human population maxing out, in fact, of our planet maxing out, has led to questions about whether human beings have reached their zenith as a species as well. In 2017, a group of researchers looking at data collected over 120 years, said that in many areas, human beings have become as good as they ever will be. According to these scientists, certain records, such as those for the fastest human being, may not increase. This does not mean that humans will no longer be able to equal them. In fact, many more may equal the record, but the limits will not be surpassed in any meaningful way.

Another example is that of height. In certain parts of Africa, the height of individuals is reported to have been declining over the years. This indicates that certain societies may already have reached the point where they cannot access enough nutrition to be able to attain the levels of height that they used to have. Since climatic and other factors have become more and more pressing, it is likely that many more societies in different parts of the planet will experience similar deficiencies, with consequences for the kind of human flourishing (or the lack thereof) that can take place.

A parallel question that is attached to whether humanity has reached its peak is a larger one about whether human beings are still evolving. Evolution refers to the capacity of humans to adapt to changing conditions in the environment and culture at a genetic level. Natural selection occurs when people’s genetic make-up can adapt to a new situation, say a hotter climate, and they are able to pass down their genes, meaning that the new members of the species that are born will possess those traits.

There have been concerns that our current make-up may no longer be working in a manner to maximise our survival.

There has been much debate about whether a gene tends to get ‘lost’ in successive generations, if it is not ‘in use’. Take for instance the genetic ability to produce vitamin C which is something the human body needs. Unlike many other mammals that have the ability to produce this vitamin internally, human beings must rely on external sources, including those of diet, to access this vital vitamin. Primates, including humans, are thought to have once had the ability to synthesise this vitamin, but can no longer do so because of evolutionary reasons.

Another case is that of the enzyme lactase that allows us to continue to digest lactose, which is present in milk and other dairy products. It is believed that thousands of years ago, the enzyme did not function as one approached adulthood. The introduction of dairy farming and the availability of yoghurt, butter, and cheese along with other dairy products created a situation where the genetic ability to continue producing that enzyme well past the post-weaning period was boosted.

However, there have been concerns that the human body’s current make-up may no longer be working in a manner that can maximise our survival in the same way it once did. One example is the common procedure known as the C-section which allows a doctor to deliver a baby when the mother cannot, for some reason — the limitations of anatomy among them — have a natural childbirth. According to a BBC report published some years ago, C-sections might be impacting our evolution. The report, quoting estimates by researchers, says that “the global rate of cases where the baby could not fit through the maternal birth canal was 3pc, or 30 in 1,000 births. Over the past 50 or 60 years, this rate has increased to about 3.3-3.6pc, so up to 36 in 1,000 births. That is about a 10-20pc increase of the original rate, due to the evolutionary effect”. The report quotes a biologist as saying: “Women with a very narrow pelvis would not have survived birth 100 years ago. They do now and pass on their genes encoding for a narrow pelvis to their daughters.”

Perhaps even a few human interventions could have genetic consequences that we are unaware of and that would have consequences that we cannot predict. Think of the many interventions we make in terms of medicine, medical procedures, or conversely, the use of harmful chemicals, burning fossil fuels in our environment, etc, and we may have a situation where we have really rattled the processes that would otherwise keep us adaptable. This does not mean that all human interventions are bad but just that we may have come to a point where we are as good as we will ever get.

Reaching peak humanity may not be the worst thing in the world, as anyone in the older generation is likely to advise; it is always good to know one’s limits. Homo sapiens have walked the earth for hundreds of thousands of years — it is truly mindboggling to contemplate the fact that we may have reached our maximum capabilities in this particular moment in time.

The writer is an attorney teaching constitutional law and political philosophy.

rafia.zakaria@gmail.com

Published in Dawn, January 5th, 2024