One of Darwin's evolution theories finally proved by Cambridge researcher • Hacker News Board

Re: One of Darwin's evolution theories finally proved by Cambridge researcher

#81

Post by Sniffnoy » Thu, Mar 19, 2020, 12:35 AM UTC

msla wrote: post #47

JumpCrisscross wrote: post #30

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.

That's not a good choice of counterexample; they're generally not considered separate species these days, largely because of that.

Re: One of Darwin's evolution theories finally proved by Cambridge researcher

#82

Post by Der_Einzige » Thu, Mar 19, 2020, 2:03 AM UTC

ausbah wrote: post #17

I wonder what adopting the idea of subspecies to evolutionary algorithms would look like, and if any benefits would be encountered.

It's been done before. Check out "cooperative coevolution"

Re: One of Darwin's evolution theories finally proved by Cambridge researcher

#83

Post by Talanes » Thu, Mar 19, 2020, 3:04 AM UTC

phkahler wrote: post #43

JumpCrisscross wrote: post #30

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 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.

Because there have always been people trading and traveling, and getting it on as they do so. People retained enough genetic connectivity to not have any massive genetic divergence. Some cosmetic differences and slightly different disease risks are not enough to make a subspecies.

Re: One of Darwin's evolution theories finally proved by Cambridge researcher

#84

Post by L_226 » Thu, Mar 19, 2020, 11:13 AM UTC

smoyer wrote: post #26

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?)

Wait until we start breeding in space, then we're really gonna be diverse. Shortly after I predict various parties on either side will start agitating to purge the others to keep the pool "clean".

Re: One of Darwin's evolution theories finally proved by Cambridge researcher

#85

Post by BaronSamedi » Thu, Mar 19, 2020, 12:10 PM UTC

bregma wrote: post #31

BaronSamedi wrote: post #14

Earlier quoted context omitted.

I think the reality is more subtle than this. Is, for example, the discovery of DNA going to be falsified? I don't think so. Is the notion that living organisms evolve going to be falsified? Again, I doubt it. The case of Newton and Einstein is relevant here. Einstein didn't "falsify" Newton but rather enriched our understanding of physics. A better model seems to be that scientific theories fit into a spectrum of ce…

The existence of DNA is an observation: it's data. That DNA is the means by which traits are passed between generations, now that's a theory. It's open to falsification. No matter how many examples you can provide showing the theory to be true, all I need to do is provide a single counterexample to prove it false.

It's easy to take basic scientific discoveries for granted. The existence of DNA and micro-organisms, for example, or that living organisms change over time were important discoveries. It wasn't that long ago when people didn't know about them. These are the types of things I meant. The mechanism by which they work is, of course, far less certain.

Re: One of Darwin's evolution theories finally proved by Cambridge researcher

#86

Post by bayesian_horse » Sat, Mar 21, 2020, 2:10 PM UTC

virtuous_signal wrote: post #78

sago wrote: post #37

Earlier quoted context omitted.

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…

At least for sexually reproductive species, your first objection could be addressed by defining the species relation as the transitive closure of the relation A ~ B if A can reproduce with B. (so for instance male1 ~ female0 and male2 ~ female0 by the original definition, and then male1 ~ male2 via the closure)

You still assume you have animals that breed when you're looking. Lot's of them don't.

And it's still about the genetic distance. You can't mate everyone to everyone. You need to cluster by phenotype,genotype or location.

Re: One of Darwin's evolution theories finally proved by Cambridge researcher

#87

Post by bayesian_horse » Sat, Mar 21, 2020, 2:13 PM UTC

msla wrote: post #47

JumpCrisscross wrote: post #30

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.

They diverged a rather long time before they started breeding again. They also seem to have other reproductive rates and behavior. They are anatomically more distant from modern Humans, than any group of modern Humans from each other.

In every sense of the word species, it makes more sense to call Neanderthals a different species.

Re: One of Darwin's evolution theories finally proved by Cambridge researcher

#88

Post by msla » Sun, Mar 22, 2020, 3:17 PM UTC

bayesian_horse wrote: post #87

msla wrote: post #47

Earlier quoted context omitted.

> 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.

They diverged a rather long time before they started breeding again. They also seem to have other reproductive rates and behavior. They are anatomically more distant from modern Humans, than any group of modern Humans from each other. In every sense of the word species, it makes more sense to call Neanderthals a different species.

> They are anatomically more distant from modern Humans, than any group of modern Humans from each other.

This makes them different subspecies, which humanity no longer has.