Sometimes there can be an immune response towards the baby. See: https://en.wikipedia.org/wiki/Hemolytic_disease_of_the_newbo...
How the placenta evolved from an ancient virus
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Re: How the placenta evolved from an ancient virus
#12Every thing about life is so fascinating. I have always wondered how viruses have persisted for so long if they need a host to survive and it took us millions of years to go from single celled to multicellular. I wish there was a way to know everything and become good at everything. :/
That would certainly be nice in some ways, but then you'd deprive yourself of the joy of learning.
Re: How the placenta evolved from an ancient virus
#13Every thing about life is so fascinating. I have always wondered how viruses have persisted for so long if they need a host to survive and it took us millions of years to go from single celled to multicellular. I wish there was a way to know everything and become good at everything. :/
I think the plain answer is that if they didn't, you wouldn't know about them. Just like all other parasites. In some sense, we're all parasites on plants, that in turn feed on the energy delivered by the giant fusion reactor in the middle of our solar system.
In the case of viruses, remember that there are viruses for much simpler organisms, like bacteria. And yes, you can use those to treat bacterial infections.
Re: How the placenta evolved from an ancient virus
#14As much as I would like to discuss but I am on my phone and typing there just sucks. The topic is a real rabbit hole in a positive sense.
Either way, I would like to thank user dragosmocrii who lead me to this article via their comment at https://news.ycombinator.com/item?id=25655272
Re: How the placenta evolved from an ancient virus
#15Wait, so placenta's existed before this virus gave us the ability for them to work? I would have guessed that the virus imparted the DNA at some earlier point, and that DNA helped a placenta evolve.
There seem to be a lot of different levels of maternal support for unborn offspring, ranging from „shelter“ by carrying eggs until they hatch to full life-support like mammals offer it.
Re: How the placenta evolved from an ancient virus
#16Every thing about life is so fascinating. I have always wondered how viruses have persisted for so long if they need a host to survive and it took us millions of years to go from single celled to multicellular. I wish there was a way to know everything and become good at everything. :/
Viruses are ultimately bits of genetic code wrapped in a shell and injection mechanism. IANAB, so this is pure conjecture, but: it wouldn't surprise me if it turned out that viruses are a kind of degenerative state - something evolution may just spit out as it makes mistakes trying to improve on cells. If that's the case, then viruses may exist simply because they are a waste product of natural selection of more complex life.
Re: How the placenta evolved from an ancient virus
#17Every thing about life is so fascinating. I have always wondered how viruses have persisted for so long if they need a host to survive and it took us millions of years to go from single celled to multicellular. I wish there was a way to know everything and become good at everything. :/
> I wish there was a way to know everything and become good at everything.
There must be some way to do it, because I constantly encounter people on the Internet, that know everything, and are good at everything.
I can’t get any of them to tell me how they do it, though...
Re: How the placenta evolved from an ancient virus
#18Every thing about life is so fascinating. I have always wondered how viruses have persisted for so long if they need a host to survive and it took us millions of years to go from single celled to multicellular. I wish there was a way to know everything and become good at everything. :/
Viruses are ultimately bits of genetic code wrapped in a shell and injection mechanism. IANAB, so this is pure conjecture, but: it wouldn't surprise me if it turned out that viruses are a kind of degenerative state - something evolution may just spit out as it makes mistakes trying to improve on cells. If that's the case, then viruses may exist simply because they are a waste product of natural selection of more comp…
There are some hypotheses that viruses are involved in the origin of life.
https://www.frontiersin.org/articles/10.3389/fmicb.2019.0052...
Re: How the placenta evolved from an ancient virus
#19Earlier quoted context omitted.
Unfortunately trying to get something useful from a viral infection is almost like trying to get bitten by a radioactive spider in order to get superpowers. The problem is that as useful as those new "features" may be, they always need many generations and many more mutations to be integrated and turn into something practically useful. In the meantime you would at best have to live with a painful spider bite and some…
The best time to plant a tree is 20 years ago.
The second best time is now :)
Re: How the placenta evolved from an ancient virus
#20I'm just realizing that several shark and snake species also give birth to live young, but I don't know whether they have placentas or similar structures. I'm sure they couldn't be homologous to mammal placentas, right? (Certainly not if this article is right about the timeline.) To what extent do viviparous animals converge when it comes to the mother/child interface? So some sharks have placentas, as mentioned in t…
Sharks are viviparous, oviparous and also ovoviviparous.
[..] There are over 500 species of shark living in waters around the world and the majority give birth to live young. The remainder are oviparous, meaning they lay eggs. [..]
[..]Whale sharks (Rhincodon typus) are the largest species of shark. Although these animals produce eggs, they don't lay them. Instead, the young hatch while still in the female's body and are born as miniature adults. This is known as ovoviviparity.[..] In some species, the female will produce unfertilised eggs, which are eaten by embryos. This is known as oophagy ('egg eating') and occurs in species including the shortfin mako (Isurus oxyrinchus) and bigeye thresher sharks (Alopias superciliosus).
Embryos of other sharks survive by feeding on their smaller siblings. This is called intrauterine cannibalism or sometimes as embryophagy ('embryo eating'). This is known to occur in sand tiger sharks (Carcharias taurus).
Placental viviparity occurs in some species of shark - once the yolk sac has been depleted, it attaches to the uterine wall, acting as a pseudoplacenta.[..]