Here's another sobering thought: you represent an unbroken chain from the universal common ancestor of successful reproduction going back billions of years and probably trillions of generations (given that many of those were as a single-celled organism). Every one of those generations a success.
So if you fail to reproduce you will break that billion year old chain of evolutionary success.
Here's another: you have 2 biological parents, (up to) 4 biological grandparents (go look at Cleopatra's family tree) and so on to an upper bound of 2^n ancestors for the n'th previous generation. At some point this number exceeds the number of organisms that were alive at that time so there are likely one or more individuals in the past who are direct ancestors to everybody.
A consequence of this is that if you go forwards in time ultimately your genetic line will either die out or you will be the direct ancestor of everybody given sufficient time.
Humans are social animals. It’s myopic I think to only evaluate based on reproduction and genetic propagation. For example, most bees and ants are not involved in reproduction but they are all involved in helping the species survive into the future. So even if you don’t reproduce you have a critical role to play in society (helping it stay cohesive, helping productivity, helping through your work efforts, helping your friends and family raise children who can help humanity survive and be good humans themselves etc)
Ants and bees in a hive have very similar genetics. Typically 75%, and sometimes 100%, if I remember.
This means that a hive in some ways is best thought of as a single organization, which happens to have a "distributed" body.
In that view, the non reproducing individuals are propagating their DNA in the same sense that human liver cells do, even though they don't have the direct involvement that down and egg cells do.
In the euchromatic regions, yeah, it's about that. Elsewhere (e.g. centromeres) we are all quite diverse. This is recent news due to long read sequencing and complete genome assembly. The human pangenome project is touching on this, if still reticent to make clear claims about the centromeres.
I'm not sure that "99%" similar is the right way to think about chimpanzees and humans. We have a different chromosome number. Our chromosome 2 is a roberstonian fusion of two acrocentric chromosomes found in all other great apes, including chimpanzees and bonobos.
> So if you fail to reproduce you will break that billion year old chain of evolutionary success.
I’m responding to this and saying that’s not an accurate way to frame it. I’m saying you are participating in evolutionary success even if you don’t reproduce. For example, a more social family where there are siblings that don’t reproduce and instead invest in the success of the reproductive sibling’s offspring is still evolutionary success and would be being selected for through your whole families reproductive success as a whole rather than your individual success.
The argument being made here is similar to the argument that sterilizing would result in removal of genes from the pool - it doesn’t work because gene selection is very complicated and doesn’t solely rely on individual reproduction.
I'm currently more focused on spreading good memes to the next generation.
Memes like kindness, empathy, planning ahead, being honest with yourself (and preferably others), communicating your intentions clearly ahead of time, and how good parenting takes more emotional labor and emotional intelligence than, say, the kind of parenting that solely consists of yelling when the parent does not receive the desired response from the child.
Genes are not the only thing the next generation needs.
I like this argument because it frames the “self”/“you” as an illusion—instead, there is a more distributed self. I recognize that there are arguments against this argument — but you point out that DNA identity is pretty distributed as well. Neat.
My mistake, I presumed incorrectly, that the argument you were making came from a place of defensiveness, rather than a more holistic framing of evolutionary success. Thanks for providing further clarity.
They are involved in helping their queen produce new offspring that also contains part of their own genetic material. In bees and ants you have to think of them as one single individual. Each single worker is not able to reproduce but they still will indirectly still reproduce through their queen. Not sure what being good humans has to do with this.
First, human beings are not bees or ants. Our nature vis-a-vis reproduction is quite different. Most human beings do reproduce as that is our nature, or certainly most of us used to with the exception of periods of social collapse (think of Rome). We're in that sort of condition now, where we are having little or no children in the developed world. This does not bode well and at some point the decline of such a society will become irreversible.
Of course, you are right that not everyone must reproduce, that there is no particular obligation for anyone to reproduce, and that those who do not can still contribute to the well-being of their families, the human species, and the common good. And indeed, if you are, say, a Catholic, you would say that while having children is the natural course and the normal path for most people, a small minority are called to sacrifice this natural end for the sake of a higher supernatural, spiritual end, e.g., the priesthood, by which one becomes a spiritual parent in place of a biological one. Certainly, we can be parental figures in non-biological ways as well. Even biological parents do that.
But that's not that we're seeing behind the present demographic decline. Something like the priesthood is an exception, not the rule. Most who can have children of their own are not having them, or many of them, not because of some kind of exceptional higher calling, but rather for morally dubious reasons. Children are demanding. They require sacrifice. They demand the love known as charity. A consumerist is going to view a child not as a gift, but a burden. Furthermore, our society demonizes families, especially large families (perhaps in part stemming from Protestant attempts to restrict Catholic populations in the US). Having many children used to be seen as a blessing, a privilege. Today, we both think we're entitled to having children (IVF is a testament to that), and refuse to have them.
I'm downvoting this because of the arrogant and dubious notion that people who've chosen not to have children are somehow morally flawed. The fact of the matter is that successfully raising, educating etc. a child is dramatically more expensive than it was a few generations ago. While we can debate the various reasons for the decline in the reproduction rate there's no doubt that this is a big one, not as many people can afford to raise kids.
The factual and pragmatic view today is that if you can't afford a large home, one parent taking a lot of time off of work, and $120K+ in education bills then you are not setting your offspring up for success, this is not based on your personal morality, it is based on economics, and on statistical observations of the population.
Ergo your lionizing of people who have have children actually amounts to a defense of the economically privileged, and you assert that the benefactors of the systemic increase of wealth inequality in our society are the most moral people. It's despicable really. Go eat your cake, pig.
I don't believe whether ones finances allowing someone to have children is the factor for whether they will. From my observation (i have not researched this; this is anecdotal), wealthier people opt to have fewer or no kids, and larger families are usually those of lower income, like there's an inverse relationship between wealth and desired number of children. Even I used to want a large family until I acquired a higher standard of living and certain luxuries that I would likely have to give up if I got married and had kids.
There's a popular line of thought that motherhood is below a working woman, and men and woman alike are enjoying increased ease of living and a consumerism lifestyle. The folk who still have to stretch and sacrifice to make ends meet already have the mindsets needed for children (sacrifice, hard work) and aren't affected by the line of belief that motherhood is 'below' since they already have learned not to compare themselves to others.
Again this is speculation. I am not a sociologist.
There used to be some truth to that but not so much anymore. It's historically correct that the poor used to have more kids (and I think are still a bit more likely to have them than the middle class). But what started to happen about 10-15 years ago was that everyone became less likely to start a family except for rich people. To be precise if a woman is rich enough to afford childcare she's much more likely to have kids.
Children are just another one of those things that is increasingly out of reach for the American middle class, along with property ownership, health care etc. For the poster I responded to to ignore the economic data and paint the middle class and ordinary human beings as being selfish and immoral is perverse.
>wealthier people opt to have fewer or no kids, and larger families are usually those of lower income, like there's an inverse relationship between wealth and desired number of children.
I've also noticed this trend, richer societies have less children and poorer societies have more children.
Absolutely no politician (aka the people charged with population and demographic concerns) actually points this out, though. Probably because it goes against a lot of narratives and the simple solution it implies is brutally unpalatable for pretty much everyone.
I also notice that every single would-be or could-be parent inquired says they can't afford it, while also clearly enjoying many luxuries that being poor would actively prohibit. I presume they all keep claiming the issue is money because who doesn't like free handouts from the government just by saying you'll have kids? Get 'em while the getting's good. I'm not talking about just the US, either.
Anyway, I believe the only true solution to declining birth rates is simply to become poor again as a society. It's the only logical solution when becoming richer clearly leads to less children.
It's not just economics. I earn a good salary and own my house, but I'm on my second marriage as both my partner and I have ADHD and Autism and in our 40s.
It's not fair to try raise a child in those conditions, so we choose not to for their sake more than ours.
No humans aren’t bees or ants. We’re social animals and you can’t ignore society and culture as aspects of evolution.
Regardless, you’ve taken this whole thing in a weird direction bringing up a demographic collapse that is a fringe theory at the moment. As for that hypothesis, there’s no actual indication that humanity is in any danger of a collapse just because the boomer generation is passing and our numbers return to normal. Humans can reproduce quite quick and have a long reproductive lifecycle - if it ever becomes a problem society will change to priority life more. As it is, life has gotten pretty difficult in terms of supporting kids and people having fewer is a symptom of that and not consumerism as you claim. And children are both a blessing and a burden. If they weren’t a burden then the statistics about teenager births and the outcome for the parents and babies wouldn’t be as bad as they are.
The person making the claim gets to present the data supporting it.
It depends on what you mean by collapse. Is it that population will decline globally for a bit to a new equilibrium point? Sure I can believe that because boomers were a huge population bubble after WWII and there have been lots of living standard advancements since then (a huge one being family planning options being more and more available to the world’s population). It’s also important to remember that the population bubble was also driven by significant life extension and health advancements in medicine and nutrition without any real birth control being available so the lag until birth control became available results in another population bubble.
None of that is particularly dire. And btw, it’s not even clear to me that the population will actually start decreasing. And even if it does, believing it’s some runaway effect that can’t be fixed within 20 years once we notice it seems myopic as well.
The position you’re taking though, that population will not only decline but that there’s no bottom to it and society will collapse, is the Elon Musk doomer talking point that this somehow portends the end of countries or civilizations or humanity itself. There’s simply no evidence and no realistic mechanism of action for something that extreme. Human populations have always ebbed and flowed and the exponential growth we’ve seen since the Industrial Revolution is not the norm nor is it sustainable.
> This is not a fringe theory. The effects of the collapse we can theorise on, but the collapse will happen now. It's not a question or a theory
Again - you’ve stated something quite extreme without providing any support and then tried to shift the responsibility for providing evidence to the person doubting your wild claim. That’s not how it works, sorry. It is a hypothesis that there’s demographic collapse until it’s either happened or there’s credible evidence it will happen. Right now afaik neither is true.
The reason this isn't a doomer Elon Musk theory is that the numbers are very counter intuitive. Add to this the fact that our average age is also rising, hiding the worrying signs even more.
Imagine we have a society with 100 people with a fertility rate of 1, that give birth at 20 and die at 80. Here is how that looks:
---
Year 0: 100 newborns (Population is actually 300 at this point)
Year 20: 100 twenties, 50 newborns
Year 40: 100 forties, 50 twenties, 25 newborns Year 60: 100 sixties, 50 forties, 25 twenties, 12 newborns
Year 80: 50 sixties, 25 forties, 12 twenties, 6 newborns
Year 100: 25 sixties, 12 forties, 6 twenties, 3 newborns
Year 120: 12 sixties, 6 forties, 3 twenties, 1 newborn
within 120 years you've gone from 300 people to 22 people
Korea is worse than this. Japan is close, Europe is getting close. A birth rate of 1 is not impossible worldwide soon.
In what world do you imagine a constant fertility rate over a 120 year period? In the 1950s everyone was concerned about overpopulation because it was so high. Now you’re concerned about a collapse because it’s low. It’s a silly fear because it’s a control system with a feedback loop. We’re just not used to seeing it oscillate because we’ve been in exponential growth for a long time, but exponential in nature must plateau and that’s what you’re seeing here.
Also you focus on individual countries and yet worldwide the population keeps increasing.
You are making a big assumption about it being cyclical. Never in history have we had contraception, it's a huge change to human behaviour. It's not at all obvious that women actually want more than 1.5 children on average in the west.
We also have tinder etc and a bunch of other changes that are HUGE in terms of culture.
I'm not saying any of these are bad, and there's not way we are going back to no contraceptives. But to ignore the effects of these, ESPECIALLY as birth rates are trending down EVERYWHERE, is pushing your head in the sand.
You are making a lot of assumptions, and as my example shows, if your assumptions are wrong for say ~50 years, you've already made a huge dent in your populations makeup.
My theory is that, as of now population might be above a "equilibrium". Since it is above equilibrium, it causes increased economic competition to raise kids. So only few economically well off couple have kid's.
After few generations, population comes back to some level where economic competition to raise kids is reduced. Also, most of the lineages of people who chose not to have kids would have been wiped out or atleast somewhat reduced (Natural selection at play). So the people living in the future are likely to have kids on the condition that there is no economic penalty.
I mean, population decline is a thing, and most 'developed' nations, or whatever you want to call us, are experiencing it. Demographic collapse sounds like a a scary term bandied about by people with an agenda (or those who want to proclaim the sky is falling but bizarrely want to ignore climate change and ecological collapse).
I'm just guessing, because I haven't encountered the term and I'm not finding much about it on google. Certainly nothing from scientific or authoritative sources. I guess one article from FT uses the term to describe China's population decline.
> Furthermore, our society demonizes families, especially large families (perhaps in part stemming from Protestant attempts to restrict Catholic populations in the US)
I think it has a lot more to do with feminism than any Protestant/Catholic divide. In the Protestant church I attend, having 6+ kids is pretty normal. Certainly many evangelicals don’t value large families but I think they’re getting that mindset from the culture, rather than sacred Scipture.
This is a perfect example of what I like to call the Eggs-Waffles Phenomenon. Basically, you can’t say something like “I like waffles” on the internet without someone replying “how dare you malign people who like eggs”. And here there’s not even a value judgement or personal preference yet this has somehow been perceived as an attack on the childless. Others have jumped in to bemoan the perceived attack on the family. It’s wild.
Nowhere do I argue that you should or shouldn’t reproduce or that either outcome affects your perceived or actual value. The word “fail” seems to be doing a lot of heavy lifting in your perceptions here.
I suspect a lot of the "woe, things are way harder for Millennials than past generations, I'm too poor to have a family" zeitgeist is actually this phenomena + literal survivorship bias. Every single person alive today came from parents that successfully reproduced. When you're a kid, it's very natural to think that having kids and a family of your own is the default state of being. After all, all of your friends have parents who successfully reproduced too.
But that's because you tend to have much closer relationships with your family and peers than with childless adults. When I change my sample from "my friends growing up" to "my parent's friends when they were growing up", a lot of them never had children. By the numbers, the percentage of households that are families with children has gone down, but it's gone from about 55% in 1970 to 40% in 2022, which is a much less drastic fall than most people would suspect. Being childless is far more normal than children believe.
You raise an interesting point, but you also seem to be conflating two things. Having children is more expensive than ever, and purchasing power has continued to drop for decades. Not to mention the drastic increase in specific "raising a family" essentials/barriers like housing costs, medical debt, educational debt, and childcare expenses. I don't have numbers to back this up, but my intuition (based on observation and casual reading) is that more working class people who actively want to have children are not doing so because they are stretched too thin than we saw in the 1970's (when people could work part-time to pay for all 4 years of college and expect a high paying career out of their degree).
Also, a 15% drop in 50 years is nothing to scoff at. In America, we are below the replacement fertility rate of 2.1 children per woman. Currently it is at 1.7, so our population would be declining without immigration. [1] This is not a bad thing in my opinion, but it is extremely significant in terms of politics, culture, and economics. If our fertility rate continues to drop expect to start hearing about it more often and at higher volume from many different corners.
Why would any of that be specific to millennials, though? The way you’re describing it nothing would have changed in a very long time.
I’m pretty sure the “I’m too poor to have a family” perspective stems directly from the wild increases we’ve see in the price of housing and not a whole lot else.
That's the point - nothing has changed, except the narrative.
The wild increases in the price of housing is a symptom of the same dynamic we've seen throughout time, of competition over resources and survival of the "fittest" (where "fittest" occasionally means most brutal/devious/selfish). The differences are that a.) The (white) Baby-boom generation (in the U.S.) bucked the trend and enjoyed abundance and very little selection pressure. Note that the story was very different if you were black (where you had the gains of the Civil Rights movement, only to have the rug pulled out from under you with the 70s inflation and 80s crack epidemic) or if you were Chinese (where you probably died in the Cultural Revolution or Great Famine) or Russian / Eastern European (where you likely drank yourself to death after the breakup of the Warsaw Pact). And b.) that in our "civilized" society, we prefer to let people die rather than kill them outright. Not so for the WW1/WW2 generation.
So if you fail to reproduce you will break that billion year old chain of evolutionary success.
True to an extent. What you really break in this case is the last inch change that your parents happened to merge in. Your extended families are still there with almost the same genotype.
I don't understand that, IMO it's more than only high cast/class men could reproduce, others were used as slaves/living tools. Isn't the main change brought by the Neolithic?
Imagine drawing your ancestry tree, parents, grandparents, etc. you will of course have as many male as female nodes. The higher variance of male reproductive success makes it likelier for two given male nodes to be filled by the same infividual, than for two given female nodes.
Ed. Of course this only works if some males have more than one reproductive partner over their life span. Serial monogamy, escapades, and polygynie are the obvious probable factors in skewing the symmetry. I might have missed some less obvious ones, but can't think of any right now.
> So if you fail to reproduce you will break that billion year old chain of evolutionary success.
All your genes are in other people and will continue without you. And your unique configuration of genetics is lost like a droplet in a river. Only around one in a billion people really put their stamp on our genealogy -- and you really need to rape, murder and empire build like Genghis Khan to achieve that kind of thing (and as the population expands it likely gets more and more difficult).
The idea of a genetic "line" is not the concept people think it is.
Humans already share 99% of their DNA. Of the 1% that creates our differences, after 5 to 7 generations, depending on how you look at it, the similarity of your descendent's DNA to your DNA would essentially be indistinguishable from noise or random variance in people who you aren't even related to at all.
Talk of lines and blood and bloodlines has more to do with people really wanting to not disappear into oblivion.
> At some point this number exceeds the number of organisms that were alive at that time so there are likely one or more individuals in the past who are direct ancestors to everybody
Wouldn’t this common ancestor be a certainty? Otherwise aren’t you betting that there were similar mutations in different lines?
>So if you fail to reproduce you will break that billion year old chain of evolutionary success.
I sincerely could not care less. As far as I'm concerned, my blood ends with me. I have absolutely no interest in continuing this endless cycle of bullshit.
You are welcome to have babby, of course, and to also do so in my stead if you are exceedingly concerned about the population count that I won't help grow or maintain, I ain't stopping you since what you do in your bedroom is none of my business (and vice versa, if the above wasn't clear enough).
There's a reason religious types recoiled from Darwin's idea. It paints God as a vivisectionist on the grandest scale.
Darwin experienced this as a father, watching his oldest child die slowly and horribly (probably from cerebral tuberculosis). It would not be a stretch to imagine this experience soured him on traditional religious dogmas.
It's a little odd to consider the idea that fighting off modern viruses today, might actually be impeding human evolution in some way we can't foresee.
There are probably thousands (and my guess would be much more) viruses that that dance on the information playground that is our genome, metagenome, and the genomes of the organisms we host. Fighting a few of them is probably not going to be a significant issue.
Having more individuals around by itself would also lead to mutations which the environment may select for in the future. By itself there is no such thing as a beneficial mutation (gene import) unless the environment proves it to be.
You're really missing the point -- there's no way to know the future. Maybe your optimism is warranted, but maybe we stamped out a virus that would have given us a superpower.
The argument is _not_ that we should change our strategy of doing the best we can with the information we have. Just that we should have some humility about what we can and can't actually predict, or say with certainty.
Our superpower is developing technology. It’s unlikely evolution could ever outperform that as it operates on much slower time scales for adaptation. So any viral mutation now will only really manifest at population scale after hundreds of thousands of years whereas technology can do it within years or decades.
You're doing a lot of work to continue to miss the point. The point is not that we should embrace viruses in order to reap the benefits. Just that it is _POSSIBLE_ that a virus would turn out to be very beneficial to humanity, in the long run. We know this to be a fact, because of the article we're reading above.
The only point I'm hoping people will take, is that we shouldn't be so quick to make categorical statements about the future; like we know exactly how things will play out. I don't know for sure. You don't know for sure. The experts don't know for sure.
No, you’re assuming a counterfactual that isn’t necessarily true. If the virus hadn’t come along, humanity as it stands today may not exist but whatever animal was infected could potentially have kept reproducing / another virus would accomplish what happened anyway. Those are far more likely scenarios.
You’re taking an impossible to prove hypothetical that would require omniscient level reasoning and predictive powers to prove or disprove - it’s not a productive line of reasoning and you’re falling into the exact same trap you’re accusing others of doing. The WWII example is also highly flawed because that one was experts making strategically reasonable calls. Worrying about some hypothetical virus that in the distant future is critical is not strategically reasonable - it’s science fantasy.
I'm not assuming anything. I'm following the science as reported in the article above. That in FACT a virus lead to an important part of human development. And was in FACT beneficial. Those are true facts, if you trust the science.
> If the virus hadn’t come along, humanity as it stands today may not exist but whatever animal was infected could potentially have kept reproducing / another virus would accomplish what happened anyway. Those are far more likely scenarios.
You literally immediately launched into assuming a counterfactual (that didn't happen, you just made it up).
> You’re taking an impossible to prove hypothetical that would require omniscient level reasoning
Yes, and I made it clear that's what I was doing. And I explicitly said it was
an imaginary situation that would never happen. I was using it for
illustrative purposes for people who are flexible enough in their thinking.
I'm sorry that isn't you.
Super powers would be sensory I think unless we sprout wings or gills. So things we've probably seen already in another species like infrared vision or what not... but we do have technology to do that already so the question is how does that influence the evolutionary landscape.
I suppose the ethical question would be: how many current humans are you willing to let die from exposure to a virus in the hopes that one of them might mutate something useful?
It's really an impossible calculation. There's no way to appraise the consequences to assign a value. If it were possible to say, that a future mutation was necessary to save humanity (ie. we are doomed without entering that future) well then perhaps we'd be willing to sacrifice a lot of us now.
It's all academic of course, we'll never make such a decision, and never know what could have been. It's just another reminder that we don't really know the future or the best course of action in these situations -- we're just taking our best guess (even the experts).
> a future mutation was necessary to save humanity
Even in that scenario, it is very simple, we protected the people today and use vaccines to induce the necessary mutation. The moral choice in my book is to always err on the side of the living than "potential of the living".
That's your personal calculus, and fair enough. World leaders might make a different decision though.
For instance, the British military planners allowed soldiers to die on the battlefield, who they could have saved, in order to protect the secret that they had cracked German encryption during WWII. That was a place where the needs of the many, were deemed more valuable than the lives of the few.
I'm not judging one way or the other, but it has happened in human history more than once. And in the imaginary scenario where leaders had perfect knowledge of the future, it would likely happen again.
That isn’t as hypothetical a situation though as what you outline which is preventing a mutation now that may be important tens, hundreds of thousands of years or maybe even millions from now. There’s so much time for technology to evolve to make it likely that any negative effects can be countered through that as technology can deal with problems on a much shorter time scale than evolution can.
> For instance, the British military planners allowed soldiers to die on the battlefield, who they could have saved, in order to protect the secret that they had cracked German encryption during WWII. That was a place where the needs of the many, were deemed more valuable than the lives of the few.
This is not a very good comparison, in my opinion. Military is rarely about the "needs of the many" far more than it is about the "powers that be". Once you understand the dynamic at a play, it is rather clear that the soldiers died for what soldiers almost always die for; the regimes that pushes them to war.
Yeah, if I remember correctly the RAG recombinases that enable crazy diversity in your B and T cell receptors of your adaptive immune system are also thought to come from a retrovirus that got into our ancestors germ cells.
Unless you think our ancestral biology is perfectly adapted to the modern world, evolution will be acting. Indeed, evolution is probably occurring on humanity at a breakneck pace right now, because our environment has changed so radically.
I think the tradeoff is worth it, viruses are far more likely to do us harm than to help us out. Besides, we're entering the age when we can direct our own evolution.
> The syncytiotrophoblast is the outermost layer of the placenta, the part that is pressed against the uterus. It’s literally a layer of cells that have fused together, forming a wall. ... There’s no other structure like this anywhere else in the body.”
> When evolutionary biologists like Chuong mapped the genomes of these cells, they found that the protein that allowed these cells to fuse into a wall, called syncytin, didn’t look like it came from human DNA. It looked more like HIV.
So the entire premise of the placenta evolving from a virus rests on the fact that the organ has a unique function requiring a unique protein in the body. Saying the source probably is a virus seems quite a leap of thought. And aren't there many highly specialized proteins in the body?
Has anybody has some more information on what protein in a retrovirus looks similar to syncytin?
If every part of a human coming from evolution, how it synchronize between each part? Is there any books explaining evolution in detail? How cell formed? How they found a way to multiply? How they choose DNA to store the information? And so on.
There is literally a world of biology (text)books that describe the process of evolution and how life came to be. I would recommend finding a syllabus at a local college for a biology class, getting the textbook second hand and then reading it
It doesn't. Everything that's poorly 'synchronized' just dies out and the more effective organisms keep reproducing. This explains basically everything past the original question of how the original self-replicating chemical reaction started.
When we design systems we seek to use (1) as few parts as we can with (2) as simple interactions between them as we can and (3) with as simple parts as we can. Cars, databases, folding chairs.
Emergent (evolved) systems use (to their benefit!) a great deal of interacting parts, with complex interactions, and with complex parts. Economies, ecologies, the Internet; to some degree, neural net AIs.
It’s possible to set aside the question of evolution vs creation, and just notice that these two categories exist, and we’re clearly in the latter.
>Which came first, the Heart, Blood Vessels or Blood? Which ones were "selected for" before the others arrived? How would a random process, uncoordinated through time select for these things and keep them while they're "not useful" until they are? etc etc
Evolutionary biologists have very detailed answers to all of these questions, plus a bunch more that are far more complicated and confounding to laypeople. You can even find some great popular science books that hold your hand and walk you through some of the absolutely mind-boggling ways in which we have found evolution to work. It doesn't require any advanced math courses to wrap your head around if you go at the topic patiently and with an open mind.
The numbers and timescales on which evolution has been operating are astronomical, far too large for a human mind to comprehend in any meaningful sense. Of course it's products are also going to be a challenge to comprehend. Especially if you start forming opinions before you have consulted the experts and put in the hard work of trying to learn how those experts know what they think they know.
It's strange that an uncoordinated, random walk of mutations would keep a profound number of changes in tact, ready for some other random bit to take place and it all just "fall into place". The eye didn't evolve. Hearing didn't evolve. Smell didn't evolve.
These explanations are always full of "must have" and "must have been". This line of thinking is just hopeful projections of desired causality.
Eyesight is just photon-sensing. There are primitive animals with primitive light/dark sensing.
Hearing is just vibration- and motion-sensing. It evolved from the lateral line in fish, which is not limited to "hearing" per se, but detects motion—current and transient pressure waves that might indicate predator or prey swimming nearby.
Smell is just chemical sensing. Catfish have chemoreceptors across their bodies.
A lot of intermediate forms are impossible to present to you as evidence because all we have is the fossil record which generally doesn't include soft tissue, which is where most of the interesting stuff happens.
One mutation that enables the slightest bit better sensing, provides an advantage, and offspring of that species in that area will gradually end up with that adaptation. Then it repeats. The "must have" is not dictated by some agent, but by environmental selective pressure, relative to pre-mutation versions of the same organism. It's induction, but for biology rather than math/cs.
It's quite possible that other types of photon and vibration and chemical sensing could have evolved, and would be superior, but we started down a path that locally descended to where we are now. And the existing tree of life would predate or out-compete pretty much any new multi-cellular life that tried to "experiment" and "evolve" novel sensing organs.
You want to talk about just-so stories? Cephalopod eyes attach to the optic nerve on the opposite (back) side of the retina, so they have no blind spot. Did a designer goof up on vertebrate eyes and not fix it, but instead implement a very complicated neurological fix involving saccades and "blinding" our brains to the instantaneous hole in our vision?
>These explanations are always full of "must have" and "must have been".
Any explanation that starts with "must have" requires that there is a single theoretical framework that could possibly apply to the world as we see it today. Since you reject this necessity, you must think there's an alternative framework that accounts for all observed phenomena (or that accounts at least as well as the theory of evolution). What is that framework?
It IS strange, using the evolutionary framework itself, that useless mutations will hang around for thousands or millions of years (countless generations) before dropping perfectly into an extremely complex system, that itself is but a small part of a larger complex system.
Evolution teaches that small, immediately useful mutations build upon one another, reinforcing the beneficial nature of the mutation. It's impossible to build large, complex life systems (with a large number of prerequisites at each step) this way. For example, the Heart, Blood Vessels and Blood. They're each extremely complex but useless without the other two.
How would evolution slowly evolve a heart with no blood or blood vessels?
How would evolution slowly evolve blood but no blood vessels or heart?
How would evolution slowly evolve a network of blood vessels but no blood to carry or heart to pump?
>How would evolution slowly build a heart with no blood or blood vessels? How would evolution slowly build blood but no blood vessels or heart? How would evolution slowly build a network of blood vessels but no blood to carry or heart to pump?
You start with a fluid-filled body cavity where oxygen is transported by dissolution from the outside to the inside. This fluid already contains oxygen-transporting cells. Then you section off part of the cavity to enable oxygen-transporting cells to move more efficiently. At this point the OTCs are completely separated, so the fluid inside the conduits can be called blood. The animal can pump blood by squeezing its body during its normal locomotion. Eventually muscle cells are added to the circulatory system to enable oxygen circulation independently of the animal's movement, as well as to circulate it even more effectively. Later on the muscle cells become centralized as it's more efficient, not to mention that a big single muscle can pump more strongly than a distributed system of tiny muscles. Each step of the way you have a functional organism and each form performs the function of transporting oxygen more effectively.
I know you're going to say that this is a "must have" explanation, but you merely asked for an explanation. The above is a plausible series of events that could have led to the circulatory system as we see it today, so if you want to argue that the circulatory system couldn't have evolved, you'll need to argue why this explanation isn't plausible.
EDIT: Also, I can't help but notice you ignored the question I asked in my last paragraph.
I'm not sure how exactly the circulatory system developed in our ancestors, but I will add that simpler circulatory systems do exist in animals today, including the open circulatory systems that are found in, e.g., arthropods. In these animals, blood is pumped across an body cavity by a heart, before flowing back through the fluid-filled body cavity itself, outside of any blood vessels. It is definitely possible to have "partial" circulatory system that functions fine while lacking some of the components present in humans.
Similarly, simpler versions of, e.g, eyes have been observed in nature with structures that are thought to be analogous to those of our early ancestors when eyes were first developing.
I guess I can see where the parent thinking you replied came from. If the life formed by randomness, according to this old Discovery video[1], it defies law of probability.
If each step from simple to complexity is using this randomness evolution, it will be more and more defies law of probability.
Wikipedia said earth had water 4.4B year ago. The first cell formed 3.8B years ago.
This PBS video[2] said multicellular life emerged 1B years ago. Other source said 1.7B years ago.
And then the first modern human appeared around 300 thousands years ago.
So the question is: is 700M-1400M years enough time for the probability to create human?
There are crappy combination padlocks that can be picked by turning the combination wheels and pulling on the shackle. When you've turned a wheel into its unlocking position the shackle will shift open slightly, signalling that you've cracked that digit. So a padlock with 3 digits could be opened in at most 30 moves, instead of 1000.
When you have a selection mechanism, the randomness of mutations becomes kind of moot. Each step of the way that produces a new adaptation only has a handful of optimal (or optimal-enough) solutions. Now, suppose that we're an underwater species that's in the process of developing light-sensitive cells, and from our present genome there are 2^64 possible genes that will produce a good protein for the transduction step (of converting light into some other form of energy). Do we need to mutate 2^64 times to find the "correct" gene? No, all of those 2^64 genes are "correct". Our descendants should not fall into the trap of thinking that because they got gene #5541741487894936799 that it was a special outcome. They could have just as easily gotten gene #5541741556614413535.
This seems to be a common thing. We're an amalgamation of different viruses and bacteria that somehow over billions of years coalesced and evolved together into what we are now. I'm never not astounded when I think about it.
I mean, everything would seem to indicate that mitochondria were assimilated while our ancestors were still microbes themselves. But that aside, our species is the result of everything that happened prior to its appearance, including for example the Cretaceous–Paleogene extinction event. Arguing that we should not attempt to prevent such events (if we're able to) because it would evolutionarily benefit the survivors is suicidal.
There's nothing special about our species. If things had happened different would the species that would have been in our place (whatever that means) be better or worse by any metric one chooses? There's no point in wondering about that.
You're assuming it happened all in one go. Instead, the protein was probably inserted into a germ cell by a retrovirus, and then was available in descendants as grist for further evolution, eventually being incorporated into the placenta.
The eye evolved in much the same way, a bit at a time. It didn't just turn up one day.
As for the virus/placenta thing, I recall reading a similar thing about wasps, though I couldn't provide any citations, that the method by which a wasp stops the immune system of a host (such as a catepiller) from attacking its eggs/larvae is viral in origin, and remarkably similar in some ways to the way a mother's body doesn't attack an organism that in any other circumstances would read as a parasite.
Strange that an uncoordinated, random walk of mutations would keep a profound number of changes in tact, ready for some other random bit to take place and it all just "fall into place". The eye didn't evolve. Hearing didn't evolve. Smell didn't evolve.
This line of thinking is just hopeful projections of desired causality.
The profound number of changes are in tact only if those changes aid in the natural selection of the organism against selection pressure.
Such changes are replicated more successfully (more offspring) making the change/mutation more resilient to disappearing from the genepool.
Over time any organism that's living/thriving is going to have a lot of these mutations stacked on top of one another in a resilient way(size of population with the same mutations). Any mutations that are disadvantageous to natural selection and proliferation are weeded out of the genepool (go extinct)
I think people are misled because it's difficult to really grasp the very high dimensionality of the space ("morphospace") in which organisms sit. There are many, many directions for incremental change to go in, and evolution just needs there to be an improving step at each point along the path. In a low dimensional space it would be easy to get stuck in local minima, but as the number of dimensions increases that's harder and harder.
Evolution can be very easy given time. Trees independently evolved from non-tree plants something like 100 times, for example.
What evidence have you considered to the contrary? Have you ever turned the chessboard around to look at this from the other side of the table?
Most people I've spoken to who have strong feelings about this topic have only ever looked at it from one side properly.
The GP is skeptical that one can go from A, a chance interaction between two systems, through a continuous uninterrupted, robust, repeatable chain of unguided interactions, and arrive at Z, the placenta. An organ whose function and elegance is unrivalled by anything we as a species have made with logic and thought.
And why should he not be skeptical, everything we've practically achieved in terms of technological progress has been the product of mind and intelligence, any claims to be able to do the same thing without that should be scrutinised very closely.
People, capable of pondering life’s great mysteries, are going to place faith into something, only difference is if they accept it as a faith or argue their faith into fact. I think this makes many here uncomfortable.
Sorry but I believe in science and evolution, not science fiction. Just making up stories that viruses can create new organs in other organisms and also some get intertwined in the reproduction so that next generations can get the same organs is creationism mythology.
Going from infecting an organ to getting replicated via meiosis and being transmitted such that it fits neatly into our chromosomes is entirely different things and different pathways. It's impossible. Exogenous viruses affected organs is real and even intertwining in our DNA, like herpes. But the idea that it can create new organs or somehow get into our sperm and egg in order to self propagate into another organism that doesn't have those genes is ridiculous.
Again, you're arguing against something that wasn't asserted. The article doesn't say some virus infected a human and bam, placenta, next generation. It says some viral infections gave us individual proteins that wound up handy later.
> the idea that it can ... somehow get into our sperm and egg in order to self propagate into another organism... is ridiculous
Again, that's precisely what endrogenous retroviruses do. From my link:
"Rarely, retroviral integration may occur in a germline cell that goes on to develop into a viable organism. This organism will carry the inserted retroviral genome as an integral part of its own genome—an "endogenous" retrovirus (ERV) that may be inherited by its offspring as a novel allele. Many ERVs have persisted in the genome of their hosts for millions of years."
