How do lookalike plants ‘know’ what to look like to avoid being eaten?


There are nettles, and there are false nettles that look very similar to nettles when not in flower. Given that the plants can’t see each other to imitate, how did the false (non-harmful) plant develop to be so visually similar to the harmful one?

In: Biology

By chance.

Evolution isn’t a choice, it’s random mutations that cause the beings to be better at surviving long enough to create offspring.

They don’t know, they just evolved that way over time as plants that look like nettles don’t get eaten so much. The same reason giraffes that have longer necks can reach the higher leaves on the trees are less likely to starve, so they are therefore more likely to continue propagating their species.

It’s just classic mimicry. Any organism may develop a specific shape altering phenotype due to random mutations, if the phenotype gets it closer to a shape where the probability of it getting attacked is reduced, the mutation persists in the gene pool. Over time the phenotype gets refined and refined until it looks intentional. If this organism happens to reside in a region where another organism is avoided by predators, then a mutation that gets it to look similar to that organism will increase its fitness. And so it eventually mimics it. It’s still random chance, but the selective pressure is not random, and it’s skewed to favor the shape of this other organism, which is why the organism may evolve towards it.

A plant looks a tiny bit like a nettle.

That plant’s children are all a bit different, and by chance some look a bit more like nettles.

the ones that look the most like nettles aren’t eaten and have their own children.

Repeat a lot for false nettles.

They don’t “know” it is just that the ones that look most like nettles or whatever else don’t get eaten so they survive to breed and more of those plants have baby plants that look like them and whatever they resemble.