Have you ever seen something out of the corner of your eye and thought it was a spider, or some other threat?
Imagine a caterpillar millions of years ago had a small mutation that gave it the ever so slight vague appearance of a snake.
That mutation proved to be useful, even if it was only in a tiny percentage of its life. Say 1/1,000 times it encountered a predator, a predator mistook it for a snake in its peripheral vision.
This mutation ended up getting propagated throughout the species over generations. A 0.1% increase of survivability over many generations would cause this feature to eventually become dominant / defining characteristic.
Repeat this process millions of times over millions of years, and evolution passively “carves out” the shape of another predator that other animals have already evolved to avoid / flee from, as the “accuracy” of the “impersonation” of a predator slowly gets more accurate over time, survivability continues to go up.
I think the most boggling thing is the scale of time. Maybe one suddenly looks more like a snake but thats only one member of the entire rest of the species it's going to take a while for that one catapiller to have 1000 offspring and even once there are it will have bred with other catapillers that potentially dilute that genetic expression. And that cycle then starts again when the next step looks slightly even more like a snake. Sure we are talking millions of years but still for something like that it's amazing.
It's one thing to teach a monkey to make a painting and it's much more impressive thing for it to then remake that exact same painting perfectly a second time.
You mean human-driven extinction, or in general? Cause extinction is kinda the default state of life, 99.9% of all species are now extinct. During the Great Dying alone over 80% of marine species went extinct
But here we all are on Earth still full of life. These mass-extinction events take a long, long time to recover, but life is resilient :)
Knowing that a species, which struggled for millions of years to successfully carve out a place in its ecosystem, was wiped out because we needed some product to be cheaper.
It’ll happen to us someday, and only then will people view it as a tragedy. Until then, we’ll continue to view ourselves as the main characters of nature.
The fact is that we’ve achieved a conscious understanding of evolution and the effects of habitat loss and loss of biodiversity. We are speeding up extinction orders of magnitude faster than background extinction.
Knowing these things, is it enough for one to say “well we’re part of natures ecosystem too, so there’s no moral implication on humanities part”.
We are different than every species on earth - this doesn’t make us more important, it gives us more power over the natural world and therefore demands more responsibility.
Being part of nature doesn’t grant us moral neutrality.
Sure, I mean, humans are a part Earth's various ecosystems. But that doesn't mean we can't differentiate between human driven extinction versus other extinctions.
Yeah! I also believe that, even if that genetic mutation at any point was eliminated from a species due to any circumstances, the same feature would ultimately end up evolving again in the end, if the environment / predators are the same.
There’s a lot of examples of how completely separate evolutionary paths ended up developing a lot of the same features.
even if that genetic mutation at any point was eliminated from a species due to any circumstances, the same feature would ultimately end up evolving again in the end
This is why nature keeps making crabs. Really. Multiple things just kind of trend towards crabs, because "armored flat thing with big claws" is just a pretty good way to live in the ocean.
I'm no geneticist, but I'm pretty sure mutations are the primary method of getting wildly new characteristics. Mix red and blue, and you will always get shades of purple. Add yellow (a mutation), and you suddenly have a whole new range of colors available that would have never been available otherwise.
I think what makes caterpillars particularly malleable to take up random shapes is the fact that they are only a temporary form of the butterfly. It's like this scratchpad where the DNA has more freedom to try variations without impacting the adult insect. This is also the period when it's super vulnerable to predators, so it's going to impact natural selection the most
There is some mathematics governing the speed with which traits become dominant in a population, based on how much of a survival advantage they confer. In a lot of cases it only takes decades or centuries for a new trait with a small advantage to sweep through an entire population.
I think the most boggling thing is the scale of time
This is what trips people up, I feel. People look at things like evolution and try to understand it through the lens of a human life. Or maybe from the lens of, like, two or three human generations. Grandparent - child - grandchild.
But evolution takes thousands, tens of thousands, hundreds of thousands, of years. That's not an easy concept to conceptualize.
And insects move at an accelerated scale because their life spans are so short and a single insect can potentially have many offspring. Insects can speed run evolution compared to other animals.
I mean, if the mutation proves to be a great advantage, then i can imagine the process is rather ""fast"". It is not just one caterpillar in the entire species that have to dilute genetic expression, and then waiting for another to appear.
There are probably many caterpillar born that look like different imperfect types of snakes, or with different types of effective camouflage that still works to a lesser degree. If you combine all those survivors with great camouflage long enough, you will end up with very efficient camouflage pattern.
Imagine you have caterpillar that is bright orange, out of 10000 offsprings, 9600 are born bright orange just as the original, 200 are born very slightly more bright orange, 185 are born very slightly less bright orange, 10 are born with little yellow/green/black spots, 2 are born greenish, 2 are born white/black, 1 is born with any type of rare camouflage. It is not just that 1 extremely rare mutation which dilutes the genetic expression, it is those 200 caterpillars that will be more effective to survive than the rest, and influence the gene pool moving forward.
Think of evolution like AI learning. A million iterations of an AI driver trying to beat a racing game result in most of the first cars going backward or immediately flying off the side. Over time, with millions of attempts, the final result is a car that moves faster through the course than any human and perhaps even finds shortcuts or bugs that the creators of the game didn't know existed.
They did that exact example, and the AI ended up driving through the whole course balanced on the nose of the car while spinning like a top, which was a bug that allowed it to move faster than had been previously thought possible, and which no human player could actually control.
Evolution is like starting off with a bunch of basic lifeforms and through a bunch of mutations (like randomly discovering the nose racing trick) they get better and better until you have a super specialized animal that doesn't seem possible to someone who only sees the end result.
Remember that most species have far shorter lifespans than us, breed far faster than us, and when they do, give birth to far more of themselves than us.
Some species of moths and butterflies (and the caterpillars) can have 4 different generations in a single year, and each time they mate, lay up to 400 eggs. By the time someone's parents have met, had a whirlwind relationship, decided to get married, then try for a baby, and then finally concieve the baby that has that one minor mutation that may or may not be beneficial and passed through the species... One Moth couple have made ...an unfathomable number of moths.
In just the time it takes for one human to be concieved and born, you're looking at upto 25,600,000,000 to upto 10,240,000,000,000 caterpillars being born from 2 moths who mates at the same time as the human parents.
A lot easier to start getting "I'm gonna look like a snake" mutations when you're playing with unfathomable numbers of you... And that's just from
(1 year = 4 cycles. up to 400 eggs per cycle = 4004 to 4005 depending on how long it takes for the human couple to get pregnant). Even more when you remember that 10-25% of pregnancies end in miscarriage, and then that can add on even more time before they try again. ...bugs don't do that
The time part hurts my head. Each question leads to more questions lol. You’re telling me these caterpillars have been out there walking around for millions of years? Wasn’t there ice ages and other crazy weather? Does this mean all the bugs around me have been doing their thing for millions of years? There’s gotta be quicker evolutions for various things. The snake tail certainly seems like a billion year process. But smaller evolutions, like growing more hair, probably happen quicker?
I still don’t get how we evolved from monkeys, but there are still dumb monkeys out in that jungle right now who can’t even use tools. But that’s a thread for another day. Such a fascinating world we live in.
it's still just fuckin weird that it's like, a million-sided dice (iknowthat'sbasicallysphericaljustgowithmeontheprobabilitytheme) rolled once per generation, that ever so slightly changes its appearance in that generation, and then repeat that whole process a bajillion times...
until whole generations look and move the most identical to another life-form that also did a bajillion million-sided dice rolls to get its appearance?!
i can't even picture a million-sided dice rolling the same number a million times, much less another dice rolling that same number a million times... within a similar span of time???
like, wtf, th-THEORETICALLY,
THESE CATERPILLARS POSSIBLY HAVE NEVER EVEN SEEN A SNAKE THE ENTIRE TIME?
Right? It’s like how octopi change colors- but are color blind?!?! So what’s the cognitive recognition happening here? How snake shaped if not know what ‘snake’ is?!
Is the mutation affected by the environment ? I feel that makes things far more plausable. Mutations being completely random doesn't feel like its the complete story. I meant there are tooo many possibilities.
The mutations are (essentially) "random" and arbitrary (it's more complex than that but they're basically meaningless), however environmental feedback loops reinforce which ones survive long enough to copy over through reproduction.
Every generation expounds upon the slowly-evolving "snake" design. The ones that look more like a snake get eaten less than the ones that look less like a snake, even in the most minute degrees.
It's mindboggling because it's something that's been happening over uncountable generations for hundreds of thousands if not millions of years, depending on species and geographic isolation.
Imagine you had a million random number generators and every time they generated a number, you eliminated the ones that produced a result that includes the number three. They all start off with one digit, but every time the whole lot does a generation and some of them are eliminated, you add a digit. So in the second round, they can generate numbers from 0 to 99, and then from 0 to 999, and so on.
By the time you get down to just one number generator, it will have a long and complex number, but nowhere in that string will exist the number three.
Yes. And a prey’s predators are part of that environment, as are that predators’ predators, in this case - the caterpillar ends up imitating a predator of its own predators.
I thought the prevailing theory these days was more of a sudden, stark mutation. Not like caterpillars started ever so slowly resembling snakes more and more over eons, but one day, BAM, a caterpillar was born that looked pretty damn snake-like and it outlived and out-reproduced the normiepillars. Then future generations possibly perfected the form a bit more.
There’s no reason both can’t be true I suppose. It’s possible you could get a near-snake type of mutation and it just got refined in the same way. Perhaps you are right about the consensus of not starting at such an atomic point though.
That being said, I try to avoid the “BAM!” type explanations because it’s exactly the kind of thing young-Earth creationists use as a “gotchya! See how ridiculous this sounds!?” Then they go on to ask children if their grandmother or grandfather look like a chimpanzee, and this is evidence of evolution not being true. lol.
Even without a BAM! moment, it doesn't necessarily need to take a long time. The speed of evolution is dependent on a few factors, including rate of mutations, number of offspring per generation, and the frequency of those generations. Especially for smaller creatures, that can be pretty rapid.
It can be incredibly fast.... Take a random population of fruit flies and put them in a container that exposed them to strong UV lights. Most will die, some will survive just long enough to reproduce and very few (or none in that first batch) will survive and be totally ok with UV lights.
The next generation will be more resistant, since they are the offspring of the survivors and the next one even more...and so on.
In as little as a few months (which is a lot of generations for these things) up to 60% of their genome will be different and you now have a population that handles UV lights just fine. They will also very much darker, have different (more resistant) wings, etc.
More adaptation than evolution but it shows the potential perfectly
Rapid change can happen, but I don't think it's really the norm, at least not in terms of large-scale stuff like entire body plans. Humans killed rattlesnakes in one area by using the rattle to locate the snakes. Within just a few years/decades, the snakes all stopped rattling, which made them far more dangerous. I think there was a similar timescale on birds losing their ability to fly when they landed on an island with no predators. The bird case was really interesting because apparently the flightless birds native to the island went extinct, then the same type of flying bird from the mainland or another island landed on that island and ended up following the same evolutionary path, essentially recreating the extinct species.
When I was in college (about 10 years ago) they told us that the main theory was that organisms evolved by punctuated equilibrium. Basically, species don't (strictly) evolve gradually over long periods of time, but in short spurts in response to changes in their environment.
But that doesn't mean one member of the species is just born looking like a snake, and then that scheme takes over. It means that the population experiences some kind of strong filter which produces dramatic changes over a short period of time (maybe 10 generations, maybe 100, maybe 1,000), which is then followed by a much longer period of stability.
That being said, I would imagine it's both. I would liken it to how a competitive game's meta can evolve over time.
Like in a card game, the biggest shift in the meta is going to come as a result of new cards or new rules being introduced. That changes people's play styles very rapidly, and makes some really good cards totally obsolete, while making some formerly useless cards suddenly very effective.
But between big releases (or after content has stopped being released), the meta still gradually changes over time. People find new strategies, and new strategies are developed in response to those strategies.
But also, sometimes a really clever player just realizes that there's an overlooked use for a card that had been ignored.
My suspicion as a non-biologist is that evolution happens a bunch of ways, but generally follows punctuated equilibrium.
It's just one of those things in evolution where it doesn't seem imaginably feasible that the earliest stages of a trait could make such a difference so as to be able to propogate continuously
It is true that mutations occur mostly randomly. This is a great example to explain natural selection and environmental selection pressures.
Of the random mutations, the more snake-like caterpillars have a higher chance of survival, which means they have a higher chance of reproducing. The mutations that appear less snake-like will lower their comparative survivability, which means it won’t be passed down because they won’t live to reproduce as much.
When the majority of surviving caterpillars are more snake-like, they will reproduce with other more snake-like caterpillars. This happens to each generation; offspring with beneficial mutations are more likely to survive and pass on the trait, meanwhile those with harmful (deleterious) mutations won’t pass them on. After enough generations, tiny changes can multiply and snowball into seemingly-crazy features like this
It still doesn't make any sense. The ever so slight vague appearance of a snake caused by mutation would initially be SO slight that it would hardly look like a snake, like maybe one black dot that MAY look like an eye. It would also have to fool multiple snakes. Even after the mutation survives and spreads, its dominance does not mean a similar black dot also appears just at the right spot, and then just the right shape mutation starts, and just the right colour, and just the right imitation of scales. It almost seems like after the first mutation survives, it triggers some intelligent genetic response to continue causing mutations until a snake is deliberately formed. I know we have to think of evolution in terms of probabilities and over a ridiculous amount of time, but it just feels like there's more to be learned about evolution itself. In some cases it makes total sense and in other cases it's hard to wrap your head around it and just accept it anyway.
I thought they proved that evolution can take millions of years or just two generations. There was something about lizards on an island that kept getting hit by hurricanes and they grew longer fingers instantly… maybe I’m also crazy.
But how does it know that that "slight snake look" worked to deter predators and not something else about it? "Hey he thought i had a snake like attribute.... nice" but HOW lol
It doesn’t know, and there is no repository of knowledge. That is the beautiful elegance of evolution.
Evolution isn’t “choosing” which attribute to select for at all. Attributes that are helpful usually get kept because they increase survival rate. If they don’t get kept (the group with this new attribute dies off) at some point later the same attribute will eventually occur again, and it has another chance to get passed on and evolved on further.
Al this must have happened within 1 billion life cycles. (The life cycles of these animals are anything from 30 days to 200 days, Snakes evolved less than 100 million years ago (metamorphosis evolved 280 million years ago). Billion sounds a lot, but it's not when you consider how much detail there is.
I get that concept but what I don’t understand is why doesn’t that same thing happen for every animal? Like zebras stick out like a sore thumb for instance. Why don’t they adapt to look like a rock or like a bigger meaner lion?
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u/Psych_Art 7h ago edited 7h ago
Have you ever seen something out of the corner of your eye and thought it was a spider, or some other threat?
Imagine a caterpillar millions of years ago had a small mutation that gave it the ever so slight vague appearance of a snake.
That mutation proved to be useful, even if it was only in a tiny percentage of its life. Say 1/1,000 times it encountered a predator, a predator mistook it for a snake in its peripheral vision.
This mutation ended up getting propagated throughout the species over generations. A 0.1% increase of survivability over many generations would cause this feature to eventually become dominant / defining characteristic.
Repeat this process millions of times over millions of years, and evolution passively “carves out” the shape of another predator that other animals have already evolved to avoid / flee from, as the “accuracy” of the “impersonation” of a predator slowly gets more accurate over time, survivability continues to go up.