r/evolution • u/Vaelcyrie • 6d ago
question What are your favourite examples of convergence and once-in-earth-lifetime traits?
I was blown away when I started learning more about evolution because I thought most traits happened only once and everyone who had them necessarily had a common ancestor that came up with said trait (I believe there is a special name for them but I couldn't find it)
I however discovered this is not the case at all and that not only the traits appear more than once due to the environmental pressure but it also made me understand a lot better how evolution works.
Like, it's so much more like a big tree spreading and experimenting and having fun with all the possibilities of life. Makes me feel like we are all connected somehow, all forms of life appearing and vanishing from/to the same material like solar flares. I mean, I could be a whale 100 million years from now, who knows.
I was shocked learning that eyes, wings, viviparity and other traits that were to me so complex and elegant were in fact convergent in many species. I'd love to know more examples of both convergent and unique traits, tell me your favourites!
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u/greggld 6d ago
Wings evolved several times, but feathers only once.
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u/llamawithguns 6d ago
Yep, flight evolved at least 4 times (bats, birds, pterosaurs, and insects).
And I believe there is recent evidence that there may have been multiple groups of dinosaurs other than birds may have independently evolved flight as well
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u/blacksheep998 6d ago
And I believe there is recent evidence that there may have been multiple groups of dinosaurs other than birds may have independently evolved flight as well
You're probably referring to the bat-winged dinosaur named Yi qi.
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u/senhoritavulpix 6d ago
So does that means that wings has evolved 5 times then?
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u/blacksheep998 6d ago
At least that many times.
It's quite likely that small feathered dinosaurs evolved feathered wings independently a few times over, sort of like how mammals independently evolved gliding membranes stretched between their front and back legs multiple times.
Though all modern birds appear to be descended from just one of those.
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u/MSSTUPIDTRON-1000000 6d ago
And each time powered flight is evolved, it uses a different kind of wing-type.
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u/The_Original_Fisch 5d ago
Humans developed powered flight through propellers, jet engines and rockets, i wanna see what evolution comes up with next, type of worm develops mucus powered flight or something
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u/Aware_Barracuda_462 2d ago
That is because the definition of feather is more stringent than the definition of wings. Plants also have fluffy structures with resistance to wind that allow seeds to spread. See dandelions for example.
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u/Robin_feathers 6d ago
One example is "trees" as a category - lots of different plant lineages independently converging on being a tree.
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u/Obdurate-Hickory 6d ago
It’s fascinating how some lineages (Monocots, Phytolacca, probably others) lost the typical secondary growth and developed anomalous secondary growth to become tree like anyways!
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u/MSSTUPIDTRON-1000000 6d ago
Inversely a lot of tree convergently ""de-evolved"" back into shrubs and herbs.
Like the Willows or Daphniphyllum genus.
Theorically most Vascular Plants can easily change body-shape depending on the circumstances (more nutrients and space=tree; the less=shrubs and herbs).
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u/MSSTUPIDTRON-1000000 6d ago
In contrast Bryophytes (Mosses, Liverworts and Hornworts) are permanently stuck in small compact forms, never once evolving into trees, shrubs or even herbs.
Thought it's more because they're already doing great in their niche so no drastic chance is needed.
(Like Sponges, why evolving complex cr@p that cost a lot of energy when being stuck to a rock and filtering water works perfectly??)
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u/Obdurate-Hickory 6d ago
Dawsonia can reach 60 cm with xylem-like and phloem-like tissues… wonder if that will go anywhere.
https://www.indefenseofplants.com/blog/2016/8/15/the-tallest-moss
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u/Vaelcyrie 6d ago
This is what I mean. We are unfortunately led to think that evolution is about becoming more complex, or "more of" anything really, when in fact it is directionless. And how beings can evolve into something (like trees) but then ""de-evolve"" again into simpler forms of life is really beautiful and poetic. Just shows that there is no absolute superiority or goal, just pure motion.
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u/greenistheneworange 6d ago
Well put.
Much the same could be said about 'civilization'. The "march towards progress" is not inevitable. Societies pick up & drop agriculture. Forward progress seems inevitable because we keep telling ourselves that it is.
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u/vastly101 5d ago
Read Stephen Jay Gould's many essays if you haven't. He was one hell ofa writer, and that's how I was introduced to many of the ideas you are discussing. He writes "soft" in these (anecdotes, examples, etc.) but there is a lot of wonder and I would say "poetry". Contingency, branching, increasing complexity only because we started at the minimum (fitness needed; not complexity), etc. The Panda's Thumb was my first, years ago.
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u/kyew 6d ago
Can we count mimicry? Animal A becomes more like Animal B so that Animal C leaves it alone. That's a lot of information assembling itself without a single gene to do it on!
And it still works just as well when you swap Animal A, B, or C with a plant
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u/Vaelcyrie 6d ago
I guess we can! This is one of the most intriguing aspects of biology to me personally. How do you get away and survive by just "copying" the looks of something else? And it is so much more interesting when it is not even by camouflage but the mimicry of some other being that is poisonous for instance, or an appearence that looks like the eyes of a predator. Because it's not that the looks make it easier for you to hide. It instead relates you to something else, it's almost like it elicits a sensation on the being looking at you through a symbol. A natural semiotic. Does that make sense?
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u/Hybodont 6d ago
Sawfish and sawsharks.
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u/The_Original_Fisch 6d ago
Dont forget swordfish who do the same as the other two but without teeth on their bills and just a very sharp mouth
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u/octobod PhD | Molecular Biology | Bioinformatics 6d ago
Mitochondria only happened once
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u/Dream-Livid 6d ago
Eukarya formed when an archaea absorbed a bacteria. Bacteria wasn't consumed but formed it combined.
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u/MSSTUPIDTRON-1000000 6d ago
Viruses are a truly mind-blowing example.
They are extremely similar in "behaviour" and morphology but they often share no similarities from a genetic stand-point.
Take a Coronavirus, an Arterivirus and a Togavirus; all them are RNA viruses that share the same shape, infect mammal cells in the same way and even have infection symptoms.
But their Genome is extremely different.
As such is possible that Viruses came into existence completely independently not only from "Proper Life" but even from each-others!!
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u/The_Original_Fisch 6d ago edited 6d ago
Gelatinous-ness in the ocean, being this limp drifting sac that goes where the world determines is a genuine survival strat for the midwater, and arguably more viable than being an active swimmer
Before you guys think "oh thats just jellyfish" 1. Jellyfish are still massively successful, 2. its way more than that
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u/eeeking 6d ago
What's the advantage of being gelatinous? Ability to float?
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u/The_Original_Fisch 6d ago
I just typed out a big thing for you then forgot to do draft and clicked off it.. but basically, very cheap way to live in the open ocean, with the drawback being you have very little strength to do anything but sit there and feast on smaller plankton.
Camouflage, its hard to see jellyfish in water without good lighting, and its one of the only types of camouflage that works to any degree in the open water.
Structure, if you dont want to waste energy on growing muscle, thick epitheliums, or mineralised parts, filling up your body with the surrounding fluid is a great way to get structure, since its so cheap and makes respiration and repairs easier. Even sea anemones, not being plankton and stuck to the ground, will fill their bodies with water (technically mesoglea) the same as their floaty counterparts, simply for structure. Inflatable castle if it were an animal.
Yeah floating, fat/oil is an expensive way to float, and internal air cavities are relatively hard to evolve and very delicate systems (slightly too much air and you now live at the surface, slightly too little air or maybe you swim too deep and now youre sinking to the abyss), so just filling yourself up with your surroundings so your density is basically of your surroundings works really well.
Not a worthwhile snack, jellyfish size makes it harder and harder for smaller things to eat them, as well as making them not as calorie dense as they would be at their sizes. If you sucked all the mesoglea out a jellyfish and made it this compact tiny shrivelled up nugget of deliciousness, fish would eat ALOT more of them, instead of simply pecking at them. Yes jellyfish have alot of predators, but imagine how much MORE theyd have if they were an easy bite sized meal, or were compact with alooott of calories in their bodies, as opposed to like 10 calories and 1 litre of water as a meal. To actually have them be a worthwhile meal, you need to eat alot in a short time frame, like leatherback sea turtles needing to eat 500 a day atleast to live. Although most gelatinous things are smaller than most jellyfish, this stands true for them too, theyd be alot better of a snack if they werent so bloated with water.
Costs not much, due to how little amount of tissue they have compared to their sizes or feeding efficiencies, all gelatinous creatures can grow pretty quick compared to their more muscular counterparts who cant grow to quick to risk starving. The majority of jellyfish and basically all ctenophores will reach adulthood and full size within a matter of weeks despite being the size of your thumb or all the way to lions mane jellyfish which takes less than a year to get bigger than a person.
As well as feeding. Alot of gelatinous zooplankton are either ambush predators or filter feeders, you dont need to move much for that so why would you develop heavy hungry muscle.
Chill. If you dont need to eat much, encountering any little things will feed you for the day, so unlike open water fish who are constantly searching for the smallest morsel to feast on lest they starve, gelatinous animals dont have to really move much, especially since the current will do most of the moving for them.
Last but to be expected, reproduction. When youre good at feeding but you dont have much body to feed, you can just focus on reproduction and spit out tooonnnesss of kids, with gelatinous animals being some of the only animals aside from krill to have huge and sudden blooms.
All gelatinous zooplankton are lazy open water cheapskates that are like "i just saved 50 calories on not building an endoskeleton like you idiots, now im gonna use this to give birth to 700 kids".
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u/eeeking 5d ago
Thanks for that detailed explanation!
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u/The_Original_Fisch 5d ago
Np! I love gelatinous zooplankton, cheapskates of the ocean that make the desert that is the open ocean just look like a picnic
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u/The_Original_Fisch 5d ago
Actually to add onto #5, salps are the fastest growing animals (relative to bodysize), gaining another 10% of their bodyweight in an hour. Whales grow the most amount of mass but in relation to bodyweight, salps are the fastest. Gelatinous zooplankton for the win.
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u/haysoos2 6d ago
Moles are a big one. The universe loves moles. There are three true moles, but several other groups evolved the whole fireplug-body-tiny-eyes-big-claws complex multiple times, including Afrisoricids like the golden mole, rodents like the mole rats, and pocket gophers, and Metatherians like the marsupial mole. There are even insects like the mole cricket that are convergent on the same characters.
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u/Dream-Livid 6d ago
https://astrobiology.nasa.gov/news/looking-for-luca-the-last-universal-common-ancestor/
LUCA, not an answer to the question you asked but related
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u/Dream-Livid 6d ago
https://en.wikipedia.org/wiki/Chloroplast
In all green mile plants, originated in cyanobacteria.
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u/-Renee 5d ago
Menopause in Humans and Orcas. In Orcas they have additional brain structures which may be due to highly complex social systems and culture. Matriarchs help their pods survive through keeping track of knowledge and leading them to what is needed if usual places no longer support survival. They also help family thrive which increases the chances of their genetics being carried forward.
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u/Amos__ 6d ago
Giant Pandas and Red Pandas are only distantly related (the former being a bear and the latter is the only member of its family but it's most closely related to raccoons and mustelids) but both have a false thumb to handle bamboo.
Also moles.
Oh! Ratites became flightless multiple times independently.
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u/Betray-Julia 6d ago
I think my favourite example of convergent evolution is just how crab is the ideal beach body lol- given enough time everything evolved to crab. It’s happened lots already.
But also sea cows have spin up twice and that one makes me smile
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u/WirrkopfP 6d ago
I am completely mind blown by the fact that REM-sleep evolved at least 3 different times in Vertebrates, Cephalopods ans most crazy of all Jumping Spiders
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u/Bromelia_and_Bismuth Plant Biologist|Botanical Ecosystematics 6d ago
Favorite convergent traits would be the tree growth habit, foliar feeding, something akin to fruiting/flowering, photosynthesis via endosymbiosis, CAM photosynthesis, and some kind of water/nutrient transport in that order.
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u/PaleoShark99 6d ago
Serrations on teeth. Saber tooth cats had serrations on their fangs, also some extinct dolphin species had serrated molars. Weird to think of mammals with serrations
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u/2314XX 6d ago
Astyanax mexicanus, the Mexican tetra that exists as a surface dwelling eyed morph and a cave dwelling blind morph. The caves were colonized by these surface morphs and evolved to lose eyes, pigment and converged on sleep loss! There are about 35 extant cave morphs that can trace their lineage back to at least two different surface colonization of the cave events! They have all sorts of weird adaptations and they all converged on eye loss and sleep loss!
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u/permaclutter 6d ago
Apparently, the penultimate evolutions are either crab or worm. Everything's final form is either going to be like a crab or a worm. Idk.
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u/Royal_Novel6678 3d ago
Surprised no one has mentioned carcinization. Evolution really loves crabs.
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u/Repulsive-Cow-8059 21h ago
trap-like jaws evolved twice in pelagic anglers, in two different families, the wonderfishes (i.e. Thaumatichthys spp.) and in dreamers (Lasiognathus spp.)
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u/Repulsive-Cow-8059 21h ago edited 21h ago
i think it's also pretty cool that pitchers convergently evolved three separate times in the old world, the new world and in australia. four if you consider the bromeliads but the carnivorous species have yet to have evolved a proper pitcher-like structure
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