71–80 of 88 posts
This may be the appropriate thread to remind people that Darwin was far from the be-all and end-all of evolutionary biology and much of what he said turned out to be actually mistaken. This isn't so much of an attack on him as a celebration that we've come a long way since the 19th century. Also, you should be suspicious of any argument involving non-geneticists invoking Darwin to justify such and such social outcome…
Scientific theories are not "proven", that is not how science works. All theories are always and forever open to falsification. The scientific attitude is one of eternal doubt. "Proof" is something that only exists in the realm of pure math.
Other half: it's a little tiring to be hyper rational and pedantic all the time.
Earlier quoted context omitted.
Dna could be falsified. It's incredibly low chance but it could. Just like the discovery of the bacteria that causes influenza was falsified once it became clear it's a virus. Just like the so called central dogma of DNA->RNA->protein turned out to be not so central or not so dogmatic. And Einstein definitely falsified Newton with the famous experiment with the eclipse and with more correctly showing Mercury's orbit,…
> Dna could be falsified Cool! That’s an interesting idea. I could see particular attributes of DNA being corrected, but How would a molecular basis for inheritance be disproven? After all, we see the molecule on microscopy, we modify it, etc. A dis-proof would have to remain consistent with all of that. What would that look like?
So it could be disproven, but will it? No. It definitely exists. But could it? Yep, that's how we know it exists in a scientific context. It's a bit counterintuitive, but it's the language of science. You see it in how physicists talk about discoveries - how many sigma they are. That's basically saying how likely it is the null hypothesis (sort of the falsification of the discovery) is true - and there's a point where it's so low (5 sigma traditionally) that it is considered "discovered." But that discovery is qualified with the chance that it's falsifiable.
I don't know if that was a clear explanation - if not let me know so I can try clarifying. It was something that took me a while to wrap my head around - that it's only demonstrable if falsifiable, but it's a core part of a lot of scientific theory today
Scientific theories are not "proven", that is not how science works. All theories are always and forever open to falsification. The scientific attitude is one of eternal doubt. "Proof" is something that only exists in the realm of pure math.
B-b-but my scientific consensus!!! My 97%!!! Scientific truth is clearly determined by UN/Greenpeace propaganda and mentally disturbed Swedish teenagers! Are you saying you're a climate denier?
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> there is no clear-cut definition between species It's not clear-cut in all cases. But it's clear cut bilaterally. Two organisms are in the same species if they can successfully reproduce, i.e. produce an offspring that can itself produce offspring. If they can't, they're in different species. (Multilateral fuzziness arises if A can reproduce with B, and B with C, but A not with C.)
So why are different ethnicities of humans not considered sub-species? They developed in different geographic regions with barriers, the can interbreed successfully, and they have different appearances, not just in skin color, but in things like facial features. And yet the article specifically states that humans don't have subspecies.
You may think we're different based on appearance; but the genetic material says otherwise. I might be genetically much closer to someone of different skin color and gender than to my closest geographical/ethnic/cultural neighbor who looks just like me, in terms of DNA variation.
Human beings altogether are not diverse at all genetically compared to most animal species. And if we were to use said differences to classify "races" among the human species, you can be absolutely sure skin color wouldn't correlate, nor would eye or hair color.
For better candidates, look at the HLA system for an idea of more relevant classification method (this one defines immuno-regulation profiles among us, and has been shown to drive sexual attraction towards opposites, hypothetically because it favors enhanced, combined immunity in the offspring).
But even taking such systems into account, human beings are really far from meeting any common threshold of differenciation worth being called "race" in the animal realm.
One problem when discussing species and subspecies is that there is no clear-cut definition between species, subspecies and "just some genetic diversity". The best hint is the genetic distance between any two individuals. In general, that distance is bigger between species than between subspecies. But no clear thresholds can be applied to the whole tree of life. Taxonomy is still mostly defined through differences a…
> there is no clear-cut definition between species It's not clear-cut in all cases. But it's clear cut bilaterally. Two organisms are in the same species if they can successfully reproduce, i.e. produce an offspring that can itself produce offspring. If they can't, they're in different species. (Multilateral fuzziness arises if A can reproduce with B, and B with C, but A not with C.)
Earlier quoted context omitted.
> there is no clear-cut definition between species It's not clear-cut in all cases. But it's clear cut bilaterally. Two organisms are in the same species if they can successfully reproduce, i.e. produce an offspring that can itself produce offspring. If they can't, they're in different species. (Multilateral fuzziness arises if A can reproduce with B, and B with C, but A not with C.)
> Two organisms are in the same species if they can successfully reproduce, i.e. produce an offspring that can itself produce offspring. OK, explain European Early Modern Humans and Neanderthals being different species.
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> there is no clear-cut definition between species It's not clear-cut in all cases. But it's clear cut bilaterally. Two organisms are in the same species if they can successfully reproduce, i.e. produce an offspring that can itself produce offspring. If they can't, they're in different species. (Multilateral fuzziness arises if A can reproduce with B, and B with C, but A not with C.)
So all animals are in different species to members of their same sex? I'm joking a little of course. But only to make the point that the definition of species taught in high school is very difficult to pin down. You identified one way. Even more common: not all organisms reproduce sexually. But also: some organisms (protists) perform sexual recombination separately to reproduction. And even for well known higher mamm…
My key take-away - humans have no sub-species but it can be beneficial to the species as a whole. Let's get to work people! (or perhaps we just haven't formed divisions in the human population yet?)
I found an interesting genetic distance matrix on Wikipedia https://en.m.wikipedia.org/wiki/File%3AGenetic_similarities_...
Earlier quoted context omitted.
> there is no clear-cut definition between species It's not clear-cut in all cases. But it's clear cut bilaterally. Two organisms are in the same species if they can successfully reproduce, i.e. produce an offspring that can itself produce offspring. If they can't, they're in different species. (Multilateral fuzziness arises if A can reproduce with B, and B with C, but A not with C.)
So all animals are in different species to members of their same sex? I'm joking a little of course. But only to make the point that the definition of species taught in high school is very difficult to pin down. You identified one way. Even more common: not all organisms reproduce sexually. But also: some organisms (protists) perform sexual recombination separately to reproduction. And even for well known higher mamm…
What if they are the same species but just aren't that interested in each other?