We are Not Descended from Monkeys

By Victor M Fontane

1. We are not descended from monkeys

Modern humans, the species Homo sapiens, did not evolve from monkeys, but rather shares a common ancestor with them.

"A very common mistake is to think that 'we are descended from monkeys'. This mistake makes many people deny the theory of evolution," Spanish paleoanthropologist José María Bermúdez de Castro explained to BBC Mundo and according to the intriguing find of a skull that questions the ideas we have about the ancestors of humans.

"To begin with, it is better to affirm that we are one more species of the primate order," said the coordinator of the Paleobiology Program of the National Center for Research on Human Evolution of Burgos and co-director of the research project and excavations in the deposits of the Sierra de Atapuerca .

This line of primates, "begins its evolutionary history about 7 million years ago. At that time, a common ancestor with chimpanzees diverged into two different lineages, probably due to climatic reasons."

"The lineage that gave rise to the chimpanzees, Pan paniscus and Pan troglodytes, remained in West Africa. The lineage that ultimately gave rise to modern humanity evolved in South and East Africa."

Bermúdez de Castro added that we share about 99% of our genes with chimpanzees, but the difference (approximately 1.2%) is important, since we have between 20,000 and 25,000 operational genes.

"We should ponder our close relationship with these primates, our first cousins," added the Spanish scientist.

2. More than half of your body is not human.

It is estimated that about half of the human body is made up of human cells, but the rest is a mix of bacteria, viruses and fungi that make up what is known as the microbiome.

That microbiome, which is as peculiar to each person as their fingerprint, influences a wide variety of functions ranging from digestion to the immune system.

"You are 43% human according to the most recent estimates, if you count all the cells," Professor Rob Knight of the University of California, San Diego told the BBC in 2018.

If we think in genetic terms, the numbers are even more surprising. Microbiologists from Harvard Medical School and the Joslin Diabetes Center analyzed DNA from about 3,500 samples from the mouth and intestines.

The results of the work, published this year in the journal Cell Host & Microbe, indicate that there were about 46 million bacterial genes, 24 million in the microbiome of the mouth and 22 million in the intestines.

3. We are full of evolutionary vestiges.

Evolution is a process that can be very slow and some of its vestiges can remain long after they cease to fulfill a function.

The "abominable mystery" that puzzled Charles Darwin during his last years of life.

An example is the appendix, which in our ancestors would have fulfilled a function related to the digestion of plant cellulose.

Another example is wisdom teeth, which were useful for grinding fibrous foods.

The coccyx is also considered an evolutionary vestige that in the past contributed to maintaining balance. The coccyx is the vestige of a tail that in the case of human embryos appears towards the end of the fourth week of embryonic development to disappear at the beginning of the eighth week.

And if you bristle when you're feeling cold or stressed, that means your muscle fibers known as arrector pili are involuntarily contracting, which is sure to give you the chills.

If you are an animal in the wild, having your hair stand on end can be helpful, as your hairs can trap more air to retain heat. Or you may appear larger than you are, which could put off your predators.

But in the case of humans, our arrector pili do not provide any of those benefits.

4. Our species emerged about 300,000 years ago.

The story of our origins is constantly changing as new fossils are discovered. "Our species, Homo sapiens, emerged in Africa just over 200,000 years ago. Some researchers think that certain fossils from a Moroccan site (Jebel Irhoud) already belonged to our species. Those fossils are 315,000 years old," explained Bermúdez de Castro. "Regardless of this debate in the numbers, there are no known major changes in the environment of Africa in this Pleistocene epoch."

The glaciations affected the northern hemisphere and had an impact on the weakening of the Homo neanderthalensis species.

"But in sub-Saharan Africa and North Africa the climate did not undergo any notable changes. So it is difficult for us to know what circumstances favored the emergence of the first hominids similar to us in most of their anatomy."

"Certain cultural aspects such as art or symbolism would still take a while to consolidate in Homo sapiens. But from an anatomical point of view, African humans of 200,000 years ago were practically indistinguishable from us."

At present, there is much discussion about the possibility that the expansions out of Africa by Homo sapiens were several and through two different places: the Levantine Corridor and the Bab El-Mandeb Strait, in the Horn of Africa.

"It would not be strange if this were the case. The data is not contradictory and does not affect the final result: we are now the only species of hominid on the planet."

5. We have not stopped evolving.

We are still adapting to the world around us. An example is the rapid spread in the last 100 generations in the UK of the gene for tolerance to milk sugar, lactose.

It is estimated that around 11,000 years ago adult humans were unable to digest lactose.

As humans in certain regions began to depend on dairy production for food, their bodies adapted to digesting that food that was previously only tolerated by children.

In regions with a long tradition of dairy production, such as Europe, the population is much more lactose tolerant than in Asia. "Of course we have not stopped evolving and we will never do so as long as we remain a species of Earth," said Bermúdez de Castro. "Culture itself is having a decisive influence on our evolution. And that influence will be increasingly important, at the moment in which technology allows us to safely manipulate the human genome." "The experiments that we are aware of may not be very ethical and risk-taking. But over the years these manipulations will be possible. If we get to that point, evolutionary change would be extremely rapid.”

This information is consistent with the Hindu Vedas, Buddhist theories and other ancient wisdom about the human species appearance in our planet.