I was drawn to this side point though: the microraptor has four wings. Not like a dragon, of course, which has to be an insect, but an ordinary quadruped that used all four limbs to fly (compare that to mammals with a membrane between the forelimbs and hind limbs on each side). I imagine it must have looked like an F-35 when flying.

Seems like it turned out to be optimal to stick to two, not just for terrestrial mobility, but due to the (bidirectional!) optimization of the wishbone and the chest musculature. It’s probably hard to get enough power into the dual-mode hind limbs. Sadly the Wikipedia article on the microraptor doesn’t explore this.

You can't conclude that. Evolution is noisy and random.

Besides, birds are not unambiguously the most optimized flying vertebrates around.

Thus evolution is often random between local optima. People’s organs don’t represent perfect left/right symmetry but there’s no particular benefit for which of the two options were chosen overall. Ie swap just which lung is smaller and you get lots of problems, but swap everything and it all works.

I don't have a problem with that, but materialists don't have that luxury and use language in bad faith when do it.

Ascribing teleological explanations to evolution is technically wrong, since it doesn’t look ahead.

However, it does something very similar. Our brains process competing options, from plausible to nonsensical, before selecting an action, partly in sequence (ideation), but also in parallel (competition processing).

Evolution tries many options in parallel and sequence too. Just by actually doing them and then selecting which of those choices to keep repeating (better survival), and those to forget (extinction of genes, clusters of genes, or whole species).

So over longer time periods, it acts very teleologically. A kind of reverse teleologic by hindsight.

The same is true for the “brilliance” of this teleology. Evolution tries so many things, that it can solve very difficult problems in very novel ways.

Is that “intelligence”? Our casual usage of intelligence isn’t defined precisely enough to say one way or another.

One person would say evolution is blind, and in the short run it is. But another person might point out that evolution is anything but blind. It is an epic version of Edison’s lab, where millions or billions of false solutions are continually tried and ruled out, to find each new fitness enhancement.

It relentlessly experiments and follows the “data”.

On longer timescales, evolution is effectively teleological, highly creative and very intelligent.

And all three aspects compound over time, just like human learning and research, because evolution doesn’t just find new features, but new abstractions and modularity. Such as flexible reusable gene systems for encoding body parts, epigenetic reuse of features in different kinds of cells for different purposes or triggered and “run” by different conditions, nervous systems, etc.

Thus evolution “learned” to speed itself up over time, letting it more rapidly optimize larger more complex solutions. I.e. orders of magnitude faster creation of new novel animals, than it originally took to optimize the first cellular life, colonies of cells, etc.

Watching evolutions first billion years would not have suggested that the plethora of different intelligent animals, from octopus, parrot to human, would have been remotely possible in the time it took. Evolution’s compounding meta learning created brains, our “true” teleology, and its expansion into technological and economic expressions of the pursuit of survival. All meta extensions of evolution, found by evolution.

(Speak not of the relevant XKCD)

Of course we have not reached the end of our evolution. That will exist only when we are all extinct.

As for the direction... that is something else. Maybe we will evolve into higher intelligence, but as the Dick's story "The Golden man" or "Idiocracy" show, is the intelligence really the driving force of today?

So, we are visually, materiallistically oriented. Not all, of course, but evolution works on population size, not exceptions. Exceptions only come into an overbearing effect on cataclysmic events.

Our intelligence is what allows us to acquire and improve new adaptations without having to change our own genetics. We're able to change living environments and adapt to them multiple times in a single life span, and we went from basic language to walking on the Moon much faster than evolution is able to make meaningful changes through natural selection. It takes however many million years for a species to grow fur to adapt to cold climate; it took a spear for us to adapt by stealing other animals' fur, and couple hundred years to figure out how to make synthetic ones at scale. In that time, we adapted to almost every environment on the planet.

Intelligence very much is the driving force behind humanity.

EDIT: and we're also beating natural selection from the other end - modern medicine allows many people to live and reproduce, who without it would've died from genetic diseases. We're very good at denying the "fitness" criteria nature uses.

But evolutionary pressure also occurs within the species and for the human race $$$ has largely influenced demonstration of procreational traits.

Intelligence doesn't matter if you are smart but don't have any opportunities. The other social cues, fashion, appearance, physical fitness, health, being "funny". Are all a lot easier if you have $$$.

So many conversations around modern population fertility rates have a $ component in them.

Maybe being intelligent matters more than simple strength and coordination used to. But what kind of intelligence?

Maybe being a sociopath such that you can bully your way to CEO - or to a high enough level you meet some "darwinian fitness" threshold.

But in and of itself, being able to engineer the feat of walking on the moon didn't make all the nasa employees inherently more desirable to partners to procreate. Those employees maybe had attributes that matched with desirable procreation partners and maybe that feat brought $$$ too - but the engineering smarts alone isn't it.

"The water doesn't want anything. It's just the laws of gravity."

Intelligence comes from being able to efficiently compress highly predictive models. Any computational mechanism that is unable to do this is a low-grade intelligence. If you need the whole thing spelled out carefully for you, you're NGMI.

If anything, I would argue that human evolution has accelerated in the last few decades (at least in wealthy nations where people have a lot of control over their reproduction and enormous choice in who they marry, if they marry at all).

Consider birds. There was a good article a few days back, on why only non-toothed birds survived. Until the meteor-strike, 65M years ago, all was equal and they survived along-side. Until they were the only survivors.

What is a flying vertebrate that is not a bird? Bats are all I can think of.

I remember reading something about bombers maybe during ww2. I think if fighters were chasing them, the bombers could escape because with their large wings, they could fly high and slow and turn inside them.

the analogy being - some birds might be set up for ground operations and chasing prey, others living in a different ecosystem with high altitude cruising over long distances.

Four-winged birds dying up can easily be a complete accident, even more because two-winged birds were almost completely killed once too.

If they fly through the same air as airplanes, you also lose efficiency wherever you have wingtips (pressure below leaks above, basically), and the rear wings can get messed up by turbulence/vortices from the front wings if you're not careful.

How does the hair on arms and legs 'know' how long it is?

You can observe this on many people by looking at hair miniaturization of people who have MBP or similar -- the follicle constricts in size and the resulting hair that comes out is progressively shorter in length and diameter until the follicle is so constricted that it no longer produces hair.

growth (3 to 6 years) -> static (2 to 3 months) -> fall out -> rest -> start over

The maximum length of your hair is determined by how long it stays in the growing phase, in general this phase is longer in females than in males. And some people are naturally able to grow longer hair than others.

In pregnant females the static time is increased, i.e. the hair stays there without falling out. This makes their thick and full. After delivery this changes and the hair falls out in clumps, which is unpleasant, but it's the same hair that would have anyway fallen out earlier, it's not extra hair falling out.

If you cut the hair nothing changes, it still grows for as long as it was going to originally.

That myth about cutting hair (or shaving) to make it grow faster or whatever is not real.

I've never experienced a time where I've trimmed body hair and had it remain the same length for a couple of months.

Are you sure? I have fairly hairy body so when I use moisturizers it tends to stick to the hair instead of the skin, and since I'm trying to take care of my forearm tattoos, I trim my forearm hair on a regular basis, after a few weeks, if I look closely, I can see some hairs being around, say, 2cm long, whereas others are just barely growing out.

Look closer, the hairs are random length. You have to wait of course for them to reach natural max length, and then you'll see a randomized mix of lengths.

If you are always clipping hair they will almost all be at one length because > 90% of them are still growing and then getting trimmed. The rest (a minority) have recently fallen out and are just getting started and will be shorter.

Does that make sense?

I've always wondered if the almost universal preference for women to have long hair is linked with their ability to have long hair, while for males people (not you :) typically want it short, which matches what males are able to naturally do.

i.e. which came first? The ability for hair of a certain length, so that's what people like, or if people like hair a certain way so natural selection helps out.

Flies in particular are also among the best flyers, and yet, they use only two of their wings for flying, the other two shrank to became halteres, a sensory organ acting like a gyroscope.

Dragonflies may be the best fliers in the insect world thanks to their four independently controlled wings, but flies may be the second best, and they achieved that by losing two of their four wings. Evolution is interesting.

At the current level of O2 in the air I don't believe that flying insects can grow as large as even a hummingbird, much less an eagle.

On two different occasions, I've had ingrown toenails that had to have a procedure done because, once they started ingrowing, they wouldn't stop doing so. (It's still outward growth but still.)

The "ingrown" phenomenon occurs well after the nail has formed (it's getting pushed out from the lunula end) and is due to a combination of your toe's (hallux I assume) ideosyncratic geometry and environmental conditions, likely, as another commenter pointed out, how you innocently cut your nail.

Sorry for the pedantry but when I worked in drug development I used to research the nail unit, which, it turns out, few people do.

I've had a few of these procedures too and it never really stuck for me. Ingrown toenails kept being a problem. Then I started cutting my toenails in the flat / straight '|' sort of way and I've not have a problem since.

I figure it's worth a shout out to the few of you out there that need the help. But, again, it may not work for you too.

I suspect the cause is socks or shoes pushing against the skin at the end of the toe, causing it to grow incorrectly over many months.

An untrimmed nail pushes any sock/shoe away, solving the issue.

Just an in-office procedure using some local anesthesia and acid I think. The first time the whole cycle went on for months while I was regularly going to the podiatrist because of a fairly severe foot fracture of the same foot which may or may not have been connected.

This last time--a good 15 years later symmetrically on the other foot--I was pretty much just "Let's do this" after a couple times trying to just cut the toenail.

Obviously they don't (!) but the question is how?

The nail is the same: the lunula emits these keratinocytes in only one direction; even more weirdly it's a planar structure.

Don't cells "just" orient themselves using mechanotransduction [1] or am I missing something? That's a bit hand wavey but since cells don't form 3d structures in tissue themselves, they orient against the extracellular matrix using mechanotransduction and other growth factors.

The development of multicellular life was essentially cells learning how to orient themselves into a digestive tract.

[1] https://en.wikipedia.org/wiki/Mechanotransduction

Nails are a much older "invention of evolution" than humans: so we have to investigate there...

> how do nails and hairs manage to grow only in one direction

Like all things evolution: nails that grow backwards to not have an advantage (prolly a disadvantage), where nails that grow forwards have an advantage (climbing, clawing, scratching).

The question was how, not why.

Your answer is like saying "how does the eye focus light" and answering "so that you can see".

That still doesn't describe the underlying mechanism of the growth itself.

Looking at the work of Dr. Michael Levin regarding electric communication of cells, I tend to believe him that the main factor in actually creating tissues in their intended, correct shape, is incessant electric chatter among individual cells.

An interesting corollary would be that cancer = cells that don't cooperate/communicate with their neighboring cells anymore.

Where does the rotational sense of cilia come from? From the stereochemistry of proteins, and therefore from amino acids. The left-vs-right handedness of the base chemistry of life is exploited to get a macroscopic signal.

In plants, for example, cells replicate primarily at the tip of a bud, which allows branches to lengthen directionally rather than grow out in all directions. The plant produces growth hormones, which are transported upward throughout all branches until they reach a dead end. When they reach a dead end, they stop moving and just sit there, which causes the cells at the dead end to have a greater exposure to these growth hormones. These cells bathe in growth hormones for so long that they pass the hormone-exposure threshold that triggers cell replication.

For example, observation A might be maladaptive, but it is caused by gene B which also causes observation C, which does provide an advantage.

Think about all the cells, and the thousands/millions of jobs they do, in perfect coordination just in your fingers or hands.

It's all designed.

Just because the output of a system looks complicated does not mean that the input into a system is complicated.

According to the meaning of the verse: Who has created everything in the best way,(Quran)

everything is cut out according to its innate abilities with perfect measure and order, and put together with the finest art, in the shortest way, the best form, the lightest manner, and most practicable shape. Look at the clothes of birds, for example, and the easy way they ruffle up their feathers and continuously use them. Also, things are given bodies and dressed in forms in a wise manner with no waste and nothing in vain; they testify to their number to the necessary existence of an All-Wise Maker and point to that Possessor of Absolute Power and Knowledge

Yes! I've been saying this. Global warming seems like a given at this point, so instead of stopping it we should try to increase oxygen levels too and then stick Bombardier Beetle fire-breathing genes in back-bred Hatzegopteryxes. Those beasts had wingspans over ten meters, were apex predators, and were built like it. May as well get some dragons to look at…

> Time to welcome our new avian overlords.

Not new. Birds are theropods, same as T-Rexes. It's just a return to form.

Many factors contributed to this astonishing feat of athleticism—muscle power, a high metabolic rate and a physiological tolerance for elevated cortisol levels, among other things.

Additional fun fact the article doesn't mention:

Birds sleep with only half their brain at a time when making these long distance flights. That's why they don't doze off and fall out of the sky.

Other fun fact: Humans making long car drives also do what's called "microsleeping". Your eyes remain open and your hands stay on the wheel, but your brain goes unconscious for a couple seconds at a time. Usually, you don't even notice…

That is not correct. This particular bird (Bar-tailed Godwit) has never been observed to "dynamically soar" nor does it have the proper wing shape for that type of flight. If you ever seen Godwits in the wild, you will know why, it's a flapping only bird, they have no other mode of flight.

Albatrosses on the other hand do employ dynamic soaring and fly even greater distances than Godwit does (they can circumnavigate the Southern Ocean several times) although albatrosses have additional advantage of being able to use water for rest (Godwits cannot).

Best human gliders have glide ratio of 60. So Godwit still needs to be very efficient glider, or, what is more likely also knows how to use winds and updrafts.

100G will find the weak point on your model

You know, just a casual glider built to withstand 10 times more gravitational force than an F-15 and 15 times more than a Formula 1 car. Wild.

I know some of the early evolutionists wondered about the evolution of the feather and wing, since it seems hard to evolve in a gradual way -- a little bit of a feathery flap doesn't offer any advantages if it's not enough to glide on.

I know one of the leading theories is that they evolved to keep animals warm, since they're also good insulators. Is this still the main theory?

When I thought about this in the past, I assumed they evolved in sea creatures first - where even very small flaps or mini wings/fins could improve hydrodynamics and/or swimming control, without needing to make a single jump from useless to being able to fly. But I've not looked into whether that is the case.

Edit to add two quotes from a quick search:

"Thus, early feathers functioned in thermal insulation, communication, or water repellency, but not in aerodynamics and flight." - https://www.britannica.com/animal/bird-animal/The-origin-of-...

"Two major rival published theories are based on the roles of feathers in insulating the body against heat loss and in providing an aerodynamic surface for flight. However, because of the lack of knowledge about the roles and ecological relationships of protofeathers and of the most primitive feathers, it is not possible to test strongly either of these theories, or others as proposed in this symposium, against objective empirical observations to determine which is falsified or is the most probable" - https://academic.oup.com/icb/article/40/4/478/101404#

I'd argue that it's not science at all, because what's missing is the coordination behind it. To me, evolution is not a product of conscious effort, but an emergent behavior or the individuals and systems that participate.

Taking the "science" definition from Wikipedia: "Science is a rigorous, systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the world". With evolution, testing definitely happens, but it's not a systematic endeavor, or at least I'm not convinced that it is.

It completely made sense. I heard some research where starting about 500K year ago humans started to pair bond as a way to prevent mom and child mortality during and after childbirth and indeed Fathers are a clever invention. So yea, feathers are cool - fathers too! (for more info/reading here is a book suggestion: Eve)

And if we're talking philosophy, I think the feather doesn't exist at all, so it's even harder for me to imagine that it's a product of conscious effort. I imagine that what we humans consider feathers have near-infinite, similar-looking predecessors, proto-feathers, which differ so slightly from actual feathers that it's hard to say where the non-feather featherlike skin protrusions end, and feathers begin. What we can do of course is agree on such a line, but that further proves to me that feather is just a human concept, and that non-humans don't actually consciously interact with whatever we happen to call feathers.

So, feathers just kinda happened over time.

"Survival of the fittest" doesn't mean "That gene was gorgeous like Mr. Universe, so he won!" It means "Life threw something at a wall and this is what stuck. It died less in the face of actual real world conditions."

After you winnow away all the failed stuff, you have stuff that works. Do it for millions of years and amazingly complex and elegant stuff can emerge from the process.

I'd say invention is closer but does seem to imply agency.

I think feathers are the evolution here. Something evolved into a feather.

Randomly mashing the keyboard, then running the code hoping that it doesn't crash? Not exactly what I'd have in mind when thinking of great programmers, but to each their own.

Is it countless though? Earth is "only" 4.5 billion years old with life appearing "only" 800 million years later, which seems pretty short for something chaotic and unorganized to self-organize into the nearly unfathomable sophistication we have now. Of course, humans are bad at grokking large numbers, and I might be too biased as a God fearing man... to be clear I don't deny the realities of evolution, but I currently tend to believe that as far as abiogenesis/evolution goes, life was "seeded" in some way on the planet, i.e. given a head start vs arising spontaneously from primordial soup within 800M years. I realize that this belief doesn't really contribute anything to the scientific discussion, just musing that 800M years to create the initial life seed doesn't seem that long considering we use super computers to simulate trillion+ iterations of various models and have failed to observe similar phenomenon in terms of self-organization without outside influence.

It really depends on what you think the seed was.

The Earth is about 4.5 billion years old and we have pretty good records of life on it and the evolutionary steps that took place going about about 3 billion of those with reasonable evidence of life for another billion before that (the 800 million years later part that you reference).

So, if life got seeded onto the planet, it happened before then and would have to have been in the form of small carbon-based molecules.

There's some debate in the field if life evolved genetics first or metabolism first. But the 'seed' would be the same in both cases, it's just that the pathway to get to modern life would be different.

The most compelling case that I'm aware of for these small carbon-based molecules to originate somewhere other than Earth is this paper: https://biologydirect.biomedcentral.com/articles/10.1186/174...

Essentially they show that genomes have been doubling in size on average every 350 million years or so. If you project that math backward, you end with life starting, not at the beginning of Earth, but at the beginning of time, coinciding eerily with the Big Bang.

That points to a theory that carbon, water, and other elements we thought developed later might have been created earlier in the universe than expected. That would then point to the building blocks for life being essentially 'seeded' everywhere in the universe. Waiting to wake up as soon as conditions were right.

I get the author's point, I think, but the etymology of "pen" according to wiktionary.com:

> From Middle English penne, from Anglo-Norman penne, from Old French penne, from Latin penna (“feather”), from Proto-Indo-European péth₂r̥ ~ pth₂én- (“feather, wing”), from peth₂- (“to rush, fly”) (from which petition). Proto-Indo-European base also root of *petra-, from which Ancient Greek πτερόν (pterón, “wing”) (whence pterodactyl), Sanskrit पत्रम् (patram, “wing, feather”), Old Church Slavonic перо (pero, “pen”), Old Norse fjǫðr, Old English feðer (Modern English feather);[1] note the /p/ → /f/ Germanic sound change.

So pens aren't called pens because we used pennaceous feathers, but because they were made of feathers, period. At least that's how I get it.

"Pennaceous feather" is a funny term too, then, meaning something like "featherlike feather"?

I'd probably render it as more like "typical feathers" or "standard feathers". Note that "typical feathers" and "feathery feathers" mean the same thing, but one is perfectly normal phrasing and the other isn't.

Really? I think it kind of does invent. Trial and error. Back propagation. Mutation. Some randomness at conception. Sure it's a personification, but not a bad one.

I thought this was a aaron comment at first, then I saw a reply button, and whitewashed comment below.

Pet peeve: People who HAVE to rebut things like superlative descriptions. They're always counterproductive, because literally nothing actually called for a rebuttal. It clutters up the conversation much worse than "well, actually" corrections.

First, evolution, through natural selection and genetic variation, is indeed capable of innovation. Complex structures and functions can arise incrementally over time. Features that provide a survival or reproductive advantage are more likely to be passed on to subsequent generations, gradually leading to complex adaptations.

The analogy of DNA needing to be like a program, CDROM, reader, and printer all in one cell is an oversimplification that misunderstands molecular biology. DNA replication, transcription, and translation are complex processes facilitated by a variety of proteins and enzymes, which themselves evolved.

Regarding Prof. Michael Behe's arguments in "Darwin's Black Box," while thought-provoking, they have been widely critiqued and refuted in the scientific community. Behe's concept of "irreducible complexity" has been shown not to preclude evolutionary origins, as numerous studies have demonstrated how complex biochemical systems can evolve from simpler precursors through natural processes.

Lastly, it's critical to approach scientific topics with an understanding based on evidence and consensus among experts. While there are always unanswered questions in science, the theory of evolution remains one of the most robust and universally accepted scientific theories, based on overwhelming evidence across different fields including genetics, paleontology, and molecular biology.

Evolution is a fact we can all see, but the engine of evolution (random mutations) is an unproven theory.

For those who have curiosity, and most engineers should have : Michael Behe was challenged by "Evolution a theory in crisis" by M. Denton

Moreover, referencing Michael Behe's concept of "irreducible complexity" and Michael Denton's "Evolution: A Theory in Crisis" does little to undermine the robust body of empirical evidence supporting evolutionary theory. These critiques, while provocative, have been extensively rebutted in peer-reviewed research. The consensus among biologists is clear and based on a wide array of studies—from genetic sequencing to fossil records—that collectively validate evolutionary theory.

To dismiss evolutionary biology as an "unproven theory" is to ignore the comprehensive and corroborative data gathered over decades. Such a stance not only misrepresents the nature of scientific inquiry, where theories are continually tested and refined but also underestimates the adaptive power of natural processes documented in both the laboratory and the wild.

Prof J. Tour (great biochemist) who devoted his life to build synthetic molecules, never ceased to explain this. Mutations break the program (DNA) and cannot create new proteins, new mechanisms, and new coordinated organs, not to say new species. Enginneers here should understand this as I do.

Such evolutionary acquisition of new function is also common in metazoans. We have observed insects become resistant to insecticides (Ffrench-Constant et al. 2000), animals and plants acquire disease resistance (Carpenter and O'Brien 1995; Richter and Ronald 2000), crustaceans evolve new defenses to predators (Hairston 1990), amphibians evolve tolerance to habitat acidification (Andren et al. 1989), and mammals acquire immunity to poisons (Bishop 1981). Recent beneficial mutations are also known in humans, such as the famous apolipoprotein AI Milano mutation that confers lowered risk to cardiovascular disease in its carriers.

example: based on our limited understanding all we can seem to confirm so far is that there was a sort of “big bang” but that doesn’t mean a “big bang” is all there was, not by a long shot

DNA is a four state bits program. Can you tell us how random mutations on a computer program (DNA) can create new proteins and new functionnal organs. What happens if you do so on a Windows or Linux program ?

I mean maybe an ancient alien wizard did it. Should we credit the alien magi instead?

I also don't believe that God has an interest in deceiving us. Which would be the only explanation to reconciling a Creation explanation with the overwhelming amount of evidence for natural selection.

I strongly disagree that it's thought-terminating to believe that God designed the universe and living things. This understanding will lead scientists to study the genius constructions, techniques, and formulas that God used in order to improve our own machines and inventions. In contrast, the belief that living things evolved by chance may cause scientists to dismiss something they don't understand as a useless evolutionary leftover, rather than studying it further to find its actual purpose (e.g. the appendix). Thus evolutionary assumptions retard scientific progress.

Dismissing a feature as leftover isn't the fault of evolution -- it's a fault of the scientist. There should at least be a potential former use identified. But that doesn't make evolution less viable.

It is indeed thought terminating to continue to hold a belief if it is not supported by evidence. The idea that organisms were formed more or less as they are, and that natural selection is only capable of minor adjustments is something that is empirically testable by observing genetic lineage, and the fossil record. But the hypothesis fails under the weight of our observations. It does really appear that organisms have a direct lineage all the way back to the most primitive forms of life. In light of this, we must reject the hypothesis and accept what the evidence tells us. To do otherwise is allow dogma to cloud our judgement.

I know I said this already, but I'd like to repeat my opinion on the intersection between religion and science: I do not believe that the creator of the universe would want us to reject the tools that they have given us to understand their universe. To do so would be to dismiss and condescend their achievement. So why do you choose to do this with evolution? Despite it being one of the most well-supported scientific theories we have? As you mentioned, you accept natural selection, so clearly you accept aspects of the theory despite it contradicting your theology. I'm sure your beliefs contradict your theology all the time across many aspects of your life. Surely you accept that a text from the bronze-age written by fallible humans and influenced by the ideas of the very specific culture that produced it is not literally 100% true?

Agreed! And doing so would of course invalidate our current understanding of how evolution works! We'd have to throw out our theory of evolution by natural selection if we ever observed a dog give birth to a non-dog!

The definition of a "species" isn't something defined by nature. Rather it's a construct that humans invented in our need to categorize things. Genetic dissimilarities one generation to the next are of course very very small. So small that adjacent members will always be of the same "species" (able to breed with each other). But cumulative changes over generations add up. So much so that if we skipped ahead many generations, we'd no longer have compatible breeding. Different "species" as we would say under our admittedly flawed categorization system. At what point in the family tree does the species change? Given that each species can breed with its adjacents? At what point does a color gradient stop being red and start being blue? As you can see, the flaw in this understanding stems only from holding onto the definition of distinct "species" as something real rather than a human creation. A useful one, don't get me wrong! But it's important to understand the fuzziness of this definition. Your argument stems from a fundamental misunderstanding of this idea.

By the way, the example above is not merely hypothetical, since species can be separated in space as well as time. We can observe this phenomenon in action through very fascinating phenomenon like "ring species".

https://en.m.wikipedia.org/wiki/Ring_species

Really cool stuff! I'd highly recommend learning about it.

  javascript:void(location.href='https://archive.is/?run=1&url='+encodeURIComponent(location.href))

  javascript:void(window.open('https://web.archive.org/web/*/'+location.href))

Or this more complicated version of the Wayback Machine one, which if you click while on an empty tab will instead give you an alert with a text field in which to type or paste whatever URL you want to look up:

  javascript:(function()%7Bif(location.href.indexOf('http')!=0)%7Binput=prompt('URL:','https://');if(input!=null)%7Blocation.href='http://web.archive.org/web/*/'+input%7D%7Delse%7Blocation.href='http://web.archive.org/web/*/'+location.href;%7D%7D)();

One of my cat's eyes is blue. One of my cat's eyes is green.

Both can be true at the same time.