All living things on this planet come into existence through a self-copying process known as reproduction. In sexually reproducing organisms, the copy isn’t exactly the same as what created it, but it does bear some similarity. In asexually reproducing organisms, the progeny is more or less a clone of what made it.

Our planet is kept in relative balance by millions of years of the mutual push-and-pull of competing organisms, organisms which have adapted to cope with each other. Also helpful is that organic proteins used by every organism in the Kingdom of Life have similar material properties relative to inorganic materials, such as say, steel or fullerene. So the incremental evolution of an organism that can overrun the Kingdom of Life with superior properties is unlikely.

However, the phenomenon has occurred at least once, in a limited context. After the Permian-Triassic extinction, 251 million years ago, about 70% of terrestrial vertebrates, including most the giant amphibians, went extinct. Most vegetation was completely wiped out, with rivers changing from a meandering to braided structure. However, one species rose above the destruction and became dominant: Lystrosaurus, a pig-sized animal with a shovel-shaped skull and massive forelimbs for burrowing. In some fossil beds, the animals makes up 95% of all vertebrate fauna. It is the only time that a single animal has dominated the world to such an extent.

The reasons for Lystrosaurus‘ survival are uncertain: some point to its barrel-shaped chest, which probably contained massive lungs suitable for extracting oxygen from the poisoned atmosphere. Whatever the case, it was the complete winner of the time by evolutionary standards, and dominated terrestrial faunas for millions of years in the early Triassic, many hundreds of times longer than human history.

If a single organism could dominate the planet to such an extent then, due to mere evolutionary chance, then in the future could we engineer organisms that can overcome the biosphere during an episode of weakness, or even at its strongest? I do think it’s possible, but the organism would either need to be smarter-than-human or reproduce more quickly than we can manage. A microbe that exploits new non-biological materials for its defensive or offensive strategies might do the trick, or perhaps Artificial Intelligence with the ability to trick humans into doing its bidding.

A reproductive threat could even come from humans alone. If scientists could find a way to accelerate the process of human maturation, a single country with the technology could overwhelm others in a historically short timeframe. This possibility seems to be frequently overlooked in discussions regarding genetic modification, which focus on mental or physical enhancement rather than acceleration of pre-existing processes like reproduction.

The current tenuous balance, where everyone reproduces at pretty much the same speed, is likely to be toppled this century by new technologies that accelerate reproductive speeds for microbes, plants, and animals, including humans. Some people have worried about overpopulation due to life extension, but to me, modifying the exponent is a lot more significant than extending the lifespan of each individual member in the self-replicating set.

I present this idea as a counterpoint to a frequent transhumanist refrain about “progress! forward! ho!” that seems to wholeheartedly embrace every conceivable enhancement technology without considering the encyclopedia-sized list of potential downsides that we must anticipate and address in advance.