[chmod775]

This sentence doesn't make any sense: "H. sapiens doesn’t have the possibility of quickly grabbing a load of diversity by mating with another group".

It would make sense if she specifically referred to Homo sapiens sapiens, but for Homo sapiens that "other group" would be of a different species and we thus we shouldn't be able to produce fertile offspring with them.

Also Homo sapiens sapiens have plenty of genetic diversity. Even just the number of easily observable environmental adaptions present in populations are countless (Sherpa, Bajau people, etc.)

As for COVID-19, most people are more-or-less unaffected by it. Our genetic diversity is working as intended.

[thaumasiotes]

> but for Homo sapiens that "other group" would be of a different species and we thus we shouldn't be able to produce fertile offspring with them.

That's one definition of "species" (specifically, it's "the biological species concept"), but like all the other definitions, it doesn't work and does not correspond to most usage of the term. You can read modern genetic work discussing how homo sapiens interbred with hominids of other species. You can also observe how easily different species interbreed today, like wolves (canis lupus, obligatory pack animals) and coyotes (canis latrans, solitary).

[Groxx]

It also wouldn't surprise me if "can reproduce with" isn't a transitive property (edit: actually, I'd be very surprised if it always is. genetic stuff is never that simple). So even if you try to collapse species into that strict definition, you'll still have edge cases that don't fit.

Categories are hard.

[bigbubba]

You're right, it isn't necessarily transitive. So called 'ring species' are cases where it isn't.

[scarmig]

You don't even have to go as exotic as ring species. Climb up the evolutionary tree through each of your ancestors to some slime creature a billion years ago, and then climb down to your pet dog. Each connected node in that step can interbreed, but you can't mate with Fido.

I guess it's kind of a temporal ring species.

[thaumasiotes]

Ring species are so called because their breeding relationships form a cycle. You're only describing a chain. You would have described a ring species if you could mate with your dog.

(Also note that while it's perfectly possible to walk up from humans to an ancestral slime creature, and then back down to dogs, most of the steps along that path will be shared between humans and dogs, like a Y with a very, very long leg. The recent common ancestor of humans and dogs would have already been a mammal.)

[scarmig]

The point about the most recent common ancestor is well taken, but, at least according to my layman's level understanding of ring species, the two ends of the "ring" aren't expected to interbreed. Wikipedia supports that definition (and if it's wrong, should be updated by someone more knowledgeable than myself).

[thaumasiotes]

> It also wouldn't surprise me if "can reproduce with" isn't a transitive property

"Can reproduce with" is not a transitive (or even a permanent!) property among individual humans. (For a more general transitivity allowing for the fact that it doesn't make sense to ask whether males can reproduce with males.)

[chmod775]

>You can also observe how easily different species interbreed today, like wolves (canis lupus, obligatory pack animals) and coyotes (canis latrans, solitary).

Their taxonomy predates the more modern biological classification systems though. Things have been reclassified before and I expect they will be again.

[A bit of a rant:] Any classification system that can't tell you something about the objects it classifies is objectively useless for anything but naming things. You might as well use a random name generator, draw lines in the sand in geometrically pleasing ways, and pretend it's a "system".

[thaumasiotes]

> Any classification system that can't tell you something about the objects it classifies is objectively useless for anything but naming things

They are both canis, you know. The difference in species designation tells you very little because that's not a problem that can be solved. It's not an issue of misclassification. The specific designations latrans and lupus tell you a lot.

[ithkuil]

Canis is the genus. Even barring classification mistakes, cross-species breeding across genus is not impossible, it's just very less likely to produce viable and/or fertile offspring.

A classic example is the breeding between Equus Caballus (horse) and Equus Asinus (donkey): it works and you get a Mule.

The genetic difference between the horse and the donkey is non trivial, they even have a different number of chromosomes (64 vs 62). Since the offspring gets half of their chromosomes from the father and half from the mother, the mule gets an odd number of chromosomes (63) which clogs the gamete production machine and renders the animal sterile. (See https://genetics.thetech.org/ask/ask225).

Now, dogs and wolves don't have that problem. Does it mean they are same species and that the classification was applied to eagerly?

[throwanem]

I mean, Canis dates to Linnaeus, so that it's paraphyletic should be the presumption.

[ithkuil]

what about Equus? that's also introduced by Linnaeus AFAIK; could you please explain what you mean; I'm actually a noob so please state things explicitly so I can understand things (I'm ok with looking specific things up, but it's harder to look up "between the lines" things)

[rsynnott]

> Also Homo sapiens sapiens have plenty of genetic diversity.

Humans aren’t particularly genetically diverse, given our dispersal, though as far as I know there’s some disagreement on _why_.

[nobody9999]

>Humans aren’t particularly genetically diverse, given our dispersal, though as far as I know there’s some disagreement on _why_.

That's absolutely correct. One set of hypotheses about this are population bottleneck theories[0].

As an example, the Toba Catastrophe Theory[1] posits that:

"The Youngest Toba eruption has been linked to a genetic bottleneck in human evolution about 70,000 years ago,[28][29] which may have resulted from a severe reduction in the size of the total human population due to the effects of the eruption on the global climate.[30] According to the genetic bottleneck theory, between 50,000 and 100,000 years ago, human populations sharply decreased to 3,000–10,000 surviving individuals.[31][32] It is supported by some genetic evidence suggesting that today's humans are descended from a very small population of between 1,000 and 10,000 breeding pairs that existed about 70,000 years ago.[33][34]"

Whether such theories are correct or not, they appear to fit with the lack of genetic diversity among humans.

[0] https://en.wikipedia.org/wiki/Population_bottleneck

[1] https://en.wikipedia.org/wiki/Toba_catastrophe_theory#Geneti...

[mrec]

I'd have assumed that it's largely because humans can spread to new niches via cultural evolution, which happens vastly faster than the old-fashioned biological kind. Much quicker to make a fur coat than evolve one.

[Ygg2]

You're overlooking the fact that even if easily breedable pool of foreign species existed along H. sapiens, given enough time they would either be purged or become common ancestors to everyone by now.

Since they were purged and exist as remnants in individuals' DNA.

[enkid]

If they are remanants in people's DNA, they did become common ancestors, no? Everyone's family tree collapses to the same individuals at 5500 BC, after the other humans went extinct.(1) That means we are all descended from non Homo Sapiens humans. What I'm trying to say is that they were not "purged," we are their descendants. We got most of our genetic material from the Homo Sapiens side, but there is continuity with the other species as well.

(1) https://www.scientificamerican.com/article/humans-are-all-mo...

[Ygg2]

Common ancestors are in all humans IIRC. While say Neanderthal DNA is only in subset of populations.

[enkid]

You don't necessarily have any DNA from any particular ancestor, but they would be your ancestor. This is explained in the article I linked. That means that if everybody's ancestors converged in 5500 BC, and at least one person had a Neanderthal as their ancestor, everyone has a Neanderthal ancestor.

[jimktrains2]

Species is a much more fluid term than I think you realize.

Also, we don't know that most people are more or less unaffected by covid-19. We're only beginning to understand long term affects of even mild cases. Please don't spread misinformation.

[Teever]

Ring species[1] are a particularly fascinating example of the fluidity of the concept of species.

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

[chmod775]

> Species is a much more fluid term than I think you realize.

I am aware it sometimes tells you nothing at all.

> We're only beginning to understand long term affects of even mild cases. Please don't spread misinformation.

Asymptomatic cases are not the same as mild cases.

Besides, always assuming the worst-case scenario, especially when all previous experience tells us to be optimistic, is not a workable strategy.

[jimktrains2]

My point wasn't to assume the worst, but to point out that we don't know what the long term affects of even mild cases are, and there is a non-trivial amount of mild-and-worse cases.

[holoduke]

Covid is comparable to flu with a higher mortality rate. Don't make it bigger than it is. 99.95% of the people are doing perfectly fine. Genetics are thus pretty effective

[raducu]

Please, please, please stop saying that it is comparable to the flu in any way!

I got a mild case of COVID-19, even the doctors in the hospital agreed on that; I was able to help other patients do stuff they couldn't, I could easily climb 2 floor worth of stair while 90% of the patients had to make frequent resting stops.

37 days after first symptoms, I'm still not back to my previous energy levels, I still cough, I got tinnitus in my right ear and pain when ejaculating.

None of this has ever happened with any flu or cold that I ever got.

[inglor_cz]

"I got tinnitus in my right ear and pain when ejaculating."

Uh, thanks for warning, I guess? (nervously adjusting my FFP2 mask)

[dragonwriter]

> Covid is comparable to flu with a higher mortality rate.

So, like 1918 pandemic flu?

[virmundi]

There is also evidence that the Spanish Flu was made worse by a magic new drug of the time: aspirin. Sadly we dosed people far beyond safe. We made them internally bleed to death. https://www.sciencedaily.com/releases/2009/10/091002132346.h...

By the way, here's evidence that the Spanish Flu had a 20% death rate: https://www.smithsonianmag.com/history/ten-myths-about-1918-...

[autokad]

the 1918 spanish flu death rate was around 20%. It was only in March 2020 after covid19 was mainstream news it got edited in Wikipedia to show 2% (not sure if that's changed by now), you can check the edit history. But in short, in 1918, there were coffin shortages, compared to the toilet paper shortages with covid19.

covid19 and the Spanish flu are not even in the same weight class, not even a little bit, whereas yes, like it or not, covid19 is most likely in the same weight class as the flu depending on your thresholds with the flu at .1% and CV19 around .5 to 1% (likely closer to .5%).

yes, there are some people with long term effects of cv19. that's also true of the flu. Many scientists think age related dementia is caused by repeated exposures to the flu/cold. flu/cold have also caused heart and organ damage to many, it just doesn't get reported on. 'oh, this person died of organ failure, wonder why'. It's already a proven fact that the flu has caused the onset of type 1 diabetes for example. There are also many reported cases of heart disease caused by the flu. the flu sucks.

people loose their sh*t when you talk about this. it doesn't minimize the effect of covid19, it just highlights the flu is something serious. for some reason, people are too immature to handle that. or maybe it goes against their worldview we should burn the world to the ground in order to stop covid19.

[tsimionescu]

If the flu is .1% and CV19 is between 0.5-1%,that means that it is between 5 and 10 times as deadly. I'm not sure I would call that 'about the same'.

Also, these are the numbers for CV19 given unprecedented social distancing measures, entire hospitals dedicated to it, border closures and so on. If nothing had been done, it seems likely, given regional examples like Italy's Bergamo area, the death rate could easily be 10 times what is observed today, if not more.

Equally, with much stronger and more targeted measures, the death and infection rate can be brought to essentially 0 without impacting the whole population as much, as shown by Vietnam.

It is still absurd to call a disease that has already killed many more people than malaria this year 'similar to the flu'. Sure, the flu is bad, but in conservative estimates, Covid19 is 5 times worse (and in more equal comparisons, where we would take similar measures to what we do for flu, it is probably more than 100 times worse).

[autokad]

its not a secret nor disputed that the definition of a covid19 death is anyone who happens to die and is also covid19+. its also no secret nor disputed that many hospitals have and still calling any respiratory death a covid19 death without testing if they are covid19+. even public health officials calling for forever lockdowns acknowledge at least half of all of the covid19 deaths would have died in 2020 regardless.

It also didnt help that our health system was killing covid19 patients by giving putting them too aggressively on respirators. it's an inconvenient truth you get shouted at for bringing up.

Even with these absurd metrics for mortality, its clocking in at .3%. So in my opinion, its in the same weight class as the flu, but if you have such a problem with it, that's why I qualified the statement as I said it, depending on what your threshold is.

Keep in mind, the flu at the end of 2019 going into 2020 was a particularly bad flu. the mortality rate of those going to the hospital was around 6% according to the CDC.

it would not be 100 times worse than the flu. we have so much data on covid19 now, and nothing has really changed since the cruise ships, which was basically a free experiment for the world that has been promptly ignored over and over.

[jimktrains2]

I agree that some people may think things are worse than they are. I feel like the zeitgeist, at least in my area, is a lingering uncertainty of exactly how bad things are, due to a lack of testing, and of how bad things can get, as we saw in italian and new york hospitals.

My understanding, however, is that the transmissibility of covid-19 is 3 to 10 times greater than the common flu. For instance, our local public transit agency doesn't have dozens of drivers testing positive for the flu and having symptoms each year. Coupled with the, something between 2 and 10 times greater death rate, the largest concern is overrunning hospitals if there is a bad wave in an area. As another example, because it's more transmissible, my community is also worried about getting infected because don't want to infect family if we get it, whereas I don't think we worry about the same with the flu.

My understanding of the current situation is that if everyone would wear a mask and social distance, there would be very little reason to continue with many of the other precautions that have been instituted. As you said, we live with the flu, so we don't need to make the transmissibility 0.

I'm going to be very interested to look back at this in a decade and see what we've learned and what could have been differently. How overblown, or conversely, how valid are our fears right now? The biggest problem is we just don't know, and won't for a while.

[lebuffon]

To your point about transmissibility versus Flu there is this report: https://www.cdc.gov/mmwr/volumes/69/wr/mm6937a6.htm

It looks like our protections for Covid-19 were very effective against Flu transmission at least that is the assumption.

[VLM]

The topic can only be discussed using political speech until November 3rd then on the 4th we can go back to using scientific speech.

[beowulfey]

So the definition of species being “can’t interbreed” is correct, but it doesn’t have to be a physical or biological inability to interbreed—-species can arise by being geographically separated, and merge into a new species if they eventually meet. In the same vein, two species can split from a single one if something happens to isolate a subset of a single species.