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How the placenta evolved from an ancient virus (2020)

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Re: How the placenta evolved from an ancient virus (2020)

#71

Post by InSteady »

zpeti wrote: post #63
vlovich123 wrote: post #58

Earlier quoted context omitted.

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 retur…

> demographic collapse that is a fringe theory at the moment Show me the actual numbers where this isn't a massive change in humanity in the future? 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.

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.

Re: How the placenta evolved from an ancient virus (2020)

#72

Post by safety1st »

lo_zamoyski wrote: post #49
vlovich123 wrote: post #32

Earlier quoted context omitted.

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 you…

The OP was making an observation. But I'll bite. 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 w…

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.

Re: How the placenta evolved from an ancient virus (2020)

#73

Post by dirtyhippiefree »

deadbeeves wrote: post #66
dirtyhippiefree wrote: post #44

Think about it. The species that is now Mitochondria was an entirely different species. We carry Mitochondrial DNA, while the human side is Nuclear DNA…nucleus of every cell. Birth as we know it wouldn’t have happened without a third species invading our cells. We know it as placenta. Profound that we fight microbes, but without two (that we know about), our species literally (accurate use) would not exist. At all. J…

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…

Yes, our ancestors were simpler…clearly.

We aren’t the only species with the placenta…horses, for example…

One species among many.

Re: How the placenta evolved from an ancient virus (2020)

#74

Post by derac »

BurningFrog wrote: post #60
vlovich123 wrote: post #32

Earlier quoted context omitted.

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 you…

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 d…

Human beings are 99.9% genetically similar to each other. Also, we're about 99% genetically similar to chimpanzees.

Re: How the placenta evolved from an ancient virus (2020)

#75

Post by deadbeeves »

TravisCooper wrote: post #69
deadbeeves wrote: post #65

Earlier quoted context omitted.

>It's strange that [...] An appeal to incredulity is not an argument. >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 phenome…

>An appeal to incredulity is not an argument. 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…

>They're each extremely complex

Yes. Now. Not when they first emerged.

>but useless without the other two

Unsubstantiated assertion.

>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.

Re: How the placenta evolved from an ancient virus (2020)

#76

Post by pitdicker »

pitdicker wrote: post #70

> 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 syncyti…

Paper that discusses similarities between the envelope glycoprotein of retroviruses and syncytin: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3758191/

This field is called paleovirology, and the paper also discusses in some more detail how fragments of viral DNA can end up in human DNA.

Re: How the placenta evolved from an ancient virus (2020)

#78

Post by Dalewyn »

jmyeet wrote: post #28
mlcrypto wrote: post #14

Kinda morbid thinking about all the failed mutations as laying eggs evolved into the placenta

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…

>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).

Re: How the placenta evolved from an ancient virus (2020)

#79

Post by dr_dshiv »

vlovich123 wrote: post #37
mrphoebs wrote: post #35

Earlier quoted context omitted.

I doesn't seem like the above commenter was making a value judgement.

> 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…

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.

Re: How the placenta evolved from an ancient virus (2020)

#80

Post by eks391 »

safety1st wrote: post #72
lo_zamoyski wrote: post #49

Earlier quoted context omitted.

The OP was making an observation. But I'll bite. 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 w…

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…

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.

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