What species would dominate the Earth if humans disappeared?

In a post-apocalyptic future, what would happen to life if humans disappeared? After all, it is likely that the human species extinguishes well before the sun turns into a gigantic red ball and kills all living things from the surface of the Earth.

Assuming we do not end with other sentient beings (something improbable despite our tendency to kill species), history tells us that there will be fundamental changes when man ceases to exist. to be the dominant animal species on the planet.

So if we could jump back in time about 50 million years after our disappearance, what would we find? Which animal or group of animals would relieve us as the dominant species? Will a planet of the apes be born like that of the cinema? Or will dolphins, rats, tardigrades, badroaches, pigs or ants dominate the Earth?

This question has aroused much speculation and many authors have drawn up lists of candidate species. However, before making any conjectures, we must explain what we mean by dominant species.

Limiting ourselves to the animal kingdom

One could say that the present era is the era of flowers. However, by visualizing the future, no one imagines Audrey 2 of "The Tent of Horrors" (although fictional triffids have animal characteristics, such as predatory behavior and the ability to move).

Limit ourselves to the animal kingdom, more for practical than philosophical reasons. According to some criteria, the world has always been dominated by bacteria, despite the fact that "the era of bacteria" came to an end about 1,200 million years ago. But it is not because the bacteria have ceased to exist or because their predominance has diminished, but because we tend to give more importance to the large multicellular organisms that appeared later.

According to some calculations, four out of five animals are nematodes (cylindrical worms). Thus, with these examples, it is clear that neither prevalence, nor abundance, nor diversity are essential to being the dominant way of life. Instead, we tend to think of big charismatic organizations.

The meek will inherit the Earth

There is an undeniable degree of narcissism in the way humans refer to it as "me. dominant species, as well as a tendency to grant this title to our close relatives. "Planet of the Apes" imagines that our primate parents could develop the word and adopt our technology if we give them enough time and space.

But it is unlikely that nonhuman primate societies will inherit our dominion over the Earth and that probably the apes will be extinguished before us. We are already the only living hominid who is not in danger of extinction. And it is unlikely that the crisis that could end our species has left out the other great apes. In fact, any type of extinction that affects humans would also be dangerous for organisms with similar basic physiological needs.

Although humans succumb to a global pandemic that affects few mammals, great apes are precisely the species. who are more likely to get new diseases that could eliminate them from the Earth.

Could another, more distant (primate, mammal or other) relative develop an intelligence and a society similar to ours? ? It does not seem likely either. Of all the species that, in theory, were the dominant animals at one time, humans are unique in their exceptional intelligence and manual dexterity. It can therefore be inferred that such qualities are not a requisite for being the dominant or evolving species. Evolution does not promote intelligence by itself, unless it improves survival and reproduction. It is therefore a serious mistake to think that our successors will be particularly intelligent, that they will be social beings, that they will be able to speak or that they will be technology experts.

So, can we say something about the dominant species 50 million years later? of the extinction of the human being? The answer is as disappointing as surprising. We can be pretty sure that it will not be a talking chimp, but we have no idea what it will be.

The Earth has experienced a large number of mbadive extinctions throughout its history. The diversification of life after each event has always been relatively fast and the adaptation of new species has given rise to new life forms very different from those that spawned them after surviving the previous extinction.

The small creatures that ran under the dinosaurs' feet at the end of the Cretaceous were very different from cave bears, mastodons and whales from the mammalian age. Similarly, the reptiles that survived the mbadive extinction of the Permian-Tribadic about 250 million years ago and which resulted in 90% of the marine species and 70% of the terrestrial species did not look like no longer to pterosaurs, dinosaurs and mammals. and the birds that came down.

In "The Wonderful Life: Burgess Shale and the Nature of History", the late Stephen J. Gould claimed that chance or contingency, as he did before, played a very important role in the major transitions of animal life. It is possible to debate the relative importance of contingency in the history of life, which remains a controversial issue today. However, Gould's perception that the survival of modern races can hardly be presided over after a future extinction is a lesson in humility over the complexity of evolutionary transitions.

Although it may happen that ants relieve us in the field. of the Earth, as has been speculated, it is impossible for us to know what will be these dominant ants, descendants of the current ones.

/ psg