this is an odd question, but in simpler terms; can a non-predatory organism evolve into a predatory one? can it also evolve to consume other species which came from this proto-species?

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    $\begingroup$ Do you know that all organism on Earth evolved from a single unicellular organism, right? $\endgroup$
    – L.Dutch
    Jul 17, 2020 at 19:45
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    $\begingroup$ Not quite an answer but the first extinction on Earth seems relevant. "Some of these may have evolved to eat their enigmatic predecessors..." Read more: newscientist.com/article/… $\endgroup$ Jul 17, 2020 at 19:52

1 Answer 1



First off, algae can mean a lot of things. That said, there's no reason a unicellular algae-like organism couldn't evolve into a predator. It's widely suspected that the first eukaryotic Photosynthetic organisms were probably phagocytizing the photosynthetic bacterial precursors of chloroplasts and just kept them inside instead of digesting them (there are no witnesses to these prokaryotic murders, so we have to interpret ;). If it's a primitive enough organism, it wouldn't even be hard.

There would be pressure on the algae at marginal locations with low light or nutrients to re-evolve a more animal-like food system, so there's pressure. They used to behave like this, so there's precedent. I imagine an algae that re-evolves the ability to eat other dead algae to supplement photosynthesis, or obtain scarce minerals (like the venus flytrap). One day, some mutate and digest their chloroplasts, and suddenly they need to be predators or die.

Almost ANYTHING can evolve at a unicellular level, since the organisms are so simple. You merely need to provide a logic, and mutation can explain the pathway. Once you have a unicellular predator, it's the same evolution process that led to multicellular predators before. It's not QUICK, but evolution usually isn't.


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