Many poisonous mushrooms have bright colours and other species generally don´t try to eat them. Why don´t all mushrooms evolve to have similar color?
Same goes with bee stripes. Or skunk stripes.
Also, there is this dentist fish (or shrimp?) who other fishes allow to swim to their mouths without harming it. Why don´t other small fishes adapt similar appearance for their protection? And why not some fishes - clients of this dentist animal - suddenly start to eat them? Sure, they would lose their dentist service but aren’t all the free meals better deal?
Evolution isn’t something than an organism chooses, and takes a long time. Many species are a certain way because it works in the niche that they are raised in, but when other species are imported, like rats and cats, they may not be adapted to survive.
At least one cat tried to copy skunk stripes, but it didn’t work out well for her and attracted a rapey skunk.
Some harmless species do look like harmful ones. Some kingsnakes look like venomous coral snakes, some butterflies look like poisonous Monarchs. See the various forms of mimicry.
Because the benefits outweigh the costs, and some 3’ grouper is unlikely to gain much sustenance from a 3" wrasse. I am unaware of any fish who mimic these species but what is the larger fish to do? Punish freeloaders?
But there actually are cleaner wrasse mimics. False cleanerfish and bluestriped fangblenny are little bastards. Note the discussion on their success depending on rarity.
You have to remember that ‘mimicking’ isn’t something that the animal thought of doing. It was an accident of genetics. A color mutation that happened to mimic a poisonous animal and increased the their life expectancy and reproductive success. They don’t all do it because mutations are random and not something an animal can control.
As far as the fish go, it’s a mutual benefit. The big fish needs the small fish to clean their gills and mouth of parasites. If the big fish eats the little fish that defeats the ‘purpose’. Presumably the two fish evolved in concert with each other and now depend on each other to survive.
Plenty of animals do, in fact, “bluff” their way through life as a toxic, aggressive or unpalatable other critter. It’s called Batesian mimicry. Here’s a few of the insects that try to pass for wasps, for example.
Of course, this is only a manner of speaking - the evolutionary process actually works the other way around : those guys survive and thrive, because their predators mix them up with wasps. It wasn’t a conscious decision on the flys’ part to look like wasps, they just benefited from a random mutation that made them half-decent mimics.
ETA : there are also toxic critters that mimic *other *toxic critters. In this case, the strategy is for both to benefit from the dissuasive effect without the predator(s) needing to learn two separate lessons, which would kill two critters instead of one.
(Hijack: If you liked that article, you’ll like this one even better on artificial language acquisition with the same two dolphins: Comprehension of sentences by bottlenosed dolphins, Herman et al., Cognition, 16 (1984) 129-219 (Also a full-text PDF.) )
I’m not sure that’s actually true for fungi. There are brightly coloured poisonous fungi, and dull coloured edible ones, but there are lots and lots of brightly coloured edible species, and the deadliest ones are pretty innocent-looking.
There will always be some organisms that mimic the warning signs of dangerous ones, but it’s a self-limiting phenomenon. If too many do so, then the predators will start ignoring the warning signs. In fact, if there are enough harmless mimics, then the predators might actually start seeking out the brightly-colored ones (a very easy task, since they are after all brightly-colored), and it actually becomes a disadvantage.
It’s worth noting that the thing we call a mushroom is the fruiting body of the organism - like the apple on the apple tree. There are no doubt fungal species whose spores get spread in the process of their mushrooms being eaten (thus win-win).
Chanterelles are obvious growing on the forest floor, the trick is finding them before the deer do. Morels not so much, but the deer still find them … Matsutake needs to be harvested before it emerges or the worms get it.
I would assume that the strategy of mimicry does get less effective the more species apply it - if all insects looked like wasps, the wasp-like look would no longer be associated with a stinging insect by potential predators, and if all mushrooms looked like poisonous ones, that look would no longer serve as a warning of poison. Warning colours only serve as warning as long as they are associated with a real danger frequently enough that predators can learn that to ignore them leads to bad consequences.
Thank you for fine answers. I also started to think that it is also quite improbable event that a fly gets similar appearance than a bee through mutation. And you really can’t look a half-bee, that would only be an disadvantage.
Even if you only resemble a bee 1% more closely (whatever that might mean), it could still be an advantage. So long as you can fool a certain predator, with a certain type of vision, from a certain distance and under certain lighting conditions. It is not necessary that the resemblance be anything like perfect for selection to get going. The same is true for camouflage.
Absolutely, I would say that these kinds of ‘costs vs benefits’ considerations go some way to answering the original question. I only said it could provide an advantage. If it also had the effect of making you more visible to others, any advantage might be lost.
I’m sure Brad Pitt gets more sex than you do. If you want more sex, why don’t you simply change to look like Brad Pitt? Or, knowing your son will want sex someday, why don’t you have a son who looks like Brad Pitt?
Because you can’t. You can’t choose the DNA that makes Brad Pitt look like Brad Pitt. That’s not how evolution works. If your kid happens, by chance, to draw the DNA that makes him look like Brad Pitt, and your other kid looks like Quasimodo, your Brad Pitt kid will probably get more women to sleep with him, and (assuming no birth control) you’ll have quite a few grandchildren who look like Brad Pitt, all of whom will have an easier time getting laid, too. But neither you nor your kids chose to look that way. It just happened, and it results in more children with the same look.
I think all the responses of “you can’t choose your DNA” or “animals don’t know why they do it” have misparsed the OP.
It’s only the title that implies some kind of conscious choice, the actual question being posed is not that.
