For those who are scientifically minded but not biologists, I highly recommend the Grant's "How and Why Species Multiply" [0]. It's very well written. If you're much more into population dynamics, you could give their book "Ecology and Evolution of Darwin's Finches" [1] a look. It's much more technical, being aimed at maybe upper level undergrads (in evolutionary bio) or so. They have another book, "40 Years of Evolution: Darwin's Finches on Daphne Major Island", but I haven't read that one yet. Guess I should put it on my amazon wishlist!
"And in this paper, new genetic evidence shows that after two generations, there was complete reproductive isolation from the native birds. As a result, they are now reproductively - and genetically - isolated. So they have been breeding exclusively with each other over the years."
If you have never read "The Beak of the Finch: A Story of Evolution in Our Time" [1], do yourself a favor and get a copy asap. Not only is it a realy good read on the work of the Grants and their team, it is one of the very best pop-science books I have ever read.
[1] https://www.amazon.com/Beak-Finch-Story-Evolution-Time/dp/06...
I was gobsmacked when I asked as a postdoc: "How do new species evolve" and was told: "something something physical seperation between breeding populations leading to breeding incompatibilities, but we don't really know something something"
Exactly. The biggest real example I know of is ring species. Everything else seems to be total handwaving. In fact "evolution" is just an umbrella term for many different theories about how speciation happens.
I have no problem with the theory of common ancestry. That has a lot of proof. But the idea that speciation happens EXCLUSIVELY by random mutation and "natural selection" is just handwaving theorizing. It's super hard to prove and we haven't even begun to get close to what constitutes as a proof. It's on the level of ancient people thinking the ONLY way to get fire is by rubbing some sticks together.
And yet I see the latter ("natural selection") being used by many in the scientific community to suppress other theories even though it is completely handwavy and vague. That is bullying.
Basically common descent can be rigorously defined and shown. The PROCESS by which speciation happens is poorly understood and has been a subject of much posturing by the scientific community (including popularizers like Dawkins) for decades.
(PS: if you're going to knee jerk downvote this because it criticizes "evolution", at least address it with substance.)
So these "new" birds are distinct from all the other birds on the island that they form a separate breeding group. But how distinct are they from the outsider that started it all? Would they breed with birds from that birds home island? If so, I'd say they're not really a new species but a displaced species that survived one generation of interbreeding with the locals.
While certainly interesting, I wouldn't say this is a great example of speciation. One might even argue that it's an invasive species.
Whether or not the speciation is "complete" is not really the point - the title of the article says they are "...caught in the act of becoming new species" - in fact the article highlights the difficulty in stating what determines something to be a separate species.
Yes very much so. And in fact you could already tell that that was not going to be the right answer, because also in high school, you learned that some species don't reproduce sexually.
In fact even within sexual species there are a whole range of reproductive incompatabilities: from anatomical incompatibility, to impossible fertilisation, developmental dead-ends, through to live but infertile offspring, and seemingly viable offspring with dramatically lower environmental fitness. Species are an organising model, very useful in a lot of biological reasoning, but they are not a biological absolute.
In general, whenever you were taught something black-and-white with hard boundaries in high school science, they were probably oversimplifying.
No, there are still plenty of people who sincerely believe in a flat Earth, that vaccines are a conspiracy, and that homeopathic "treatments" make them better. Best to move on and not worry about people who chose not to have evidence-based beliefs.
Maybe we have to face the fact that there's multiple ways to reach a solution and no single canonical mechanism. (essentially the point of the article)
One point is super confusing in this article, and also gives massive fodder to critics of evolution:
"We tend not to argue about what defines a species anymore, because that doesn't get you anywhere," said Prof Butlin. What he says is more interesting is understanding the role that hybridisation can have in the process of creating new species, which is why this observation of Galapagos finches is so important.
If you can't define what a species is, how can you talk about the process of creating new ones?
It seems they should be talking about the rate of gene flow between groups. "Genetically distinct" means very little because phenotypes can vary widely and still interbreed. Look at dogs, for example.
I would like to see more examples of allopatric speciation or other speciation. What they have here so far is reduced gene flow to a group of finches. Proving that none of them CAN interbreed with females is not so easy, as anecdotal evidence of females not recognizing songs of males doesn't cut it.
It's a bit like proving that an animal species has truly homosexual individuals. None of them do (except possibly for domesticated sheep) -- in fact the theory of evolution would predict that homosexuality would greatly reduce fitness, but there COULD be some members that are lifelong homosexuals, same as beta wolves etc. However to PROVE that an organism is exclusively homosexual they would need to carefuly watch it and all its pairings, however brief, its whole life.
Now, with species, you have to watch EVERY male with EVERY female around it, and vice versa. That is a huge undertaking and I doubt they did it here.
All they observed is phenotypical differences. And they haven't really explained how this is different from eg dogs, except to say that the females THEY SAW did not prefer the males' songs. Certainly this shows reduced gene flow due to preferences but not that they aren't interfertile. This is much different than a cat and a dog for example.
What I am ultimately trying to say is, I am quite skeptical that we have discovered ALL the means by which speciation occurs.
You can be a creationist or whatever else you'd like to be at this point. We barely understand how speciation really takes place, in the end we still only have theories.
I have read Lee Spetner's book "Not by Chance" which goes into the mathematics of speciation occurring exclusively by random mutation and natural selection. And it is astronomically improbable on its own terms.
This there HAVE to be forcing processes from the outside which we don't know about yet. We only guess into what they could be.
And on a related note, using evolution to explain behaviors and traits is like a religion, full of "just so" stories, in fields such as evolutionary psychology but also to explain pretty much ANY trait in a genetic fitness framework.
These "just so" stories are so pervasive yet smack of a notoriously unscientific practice and framework. All one has to do is concoct a possible way by which a trait (proto-wings, homosexuality, men becoming sleepy after an orgasm -- anything really) might confer some advantage. And the other way, such "just so" stories are used to "explain" the presence of certain traits as "the evolution of those traits" via totally untestable stories about the past.
[+] [-] onychomys|8 years ago|reply
[0] https://www.amazon.com/How-Why-Species-Multiply-Evolutionary...
[1] https://www.amazon.com/Ecology-Evolution-Darwins-Finches-Pet...
[+] [-] speps|8 years ago|reply
"And in this paper, new genetic evidence shows that after two generations, there was complete reproductive isolation from the native birds. As a result, they are now reproductively - and genetically - isolated. So they have been breeding exclusively with each other over the years."
[+] [-] PeterStuer|8 years ago|reply
[+] [-] dekhn|8 years ago|reply
[+] [-] otp124|8 years ago|reply
[+] [-] EGreg|8 years ago|reply
I have no problem with the theory of common ancestry. That has a lot of proof. But the idea that speciation happens EXCLUSIVELY by random mutation and "natural selection" is just handwaving theorizing. It's super hard to prove and we haven't even begun to get close to what constitutes as a proof. It's on the level of ancient people thinking the ONLY way to get fire is by rubbing some sticks together.
And yet I see the latter ("natural selection") being used by many in the scientific community to suppress other theories even though it is completely handwavy and vague. That is bullying.
Basically common descent can be rigorously defined and shown. The PROCESS by which speciation happens is poorly understood and has been a subject of much posturing by the scientific community (including popularizers like Dawkins) for decades.
(PS: if you're going to knee jerk downvote this because it criticizes "evolution", at least address it with substance.)
[+] [-] phkahler|8 years ago|reply
While certainly interesting, I wouldn't say this is a great example of speciation. One might even argue that it's an invasive species.
[+] [-] 627467|8 years ago|reply
Depending at what scale (in size and time) you observe, we are all one species.
Even in biology there are multiple definition of species. It shows how hard it is to pigeon-hole Life.
[+] [-] bsmithers|8 years ago|reply
[+] [-] hayksaakian|8 years ago|reply
Is it more complex than that?
[+] [-] sago|8 years ago|reply
In fact even within sexual species there are a whole range of reproductive incompatabilities: from anatomical incompatibility, to impossible fertilisation, developmental dead-ends, through to live but infertile offspring, and seemingly viable offspring with dramatically lower environmental fitness. Species are an organising model, very useful in a lot of biological reasoning, but they are not a biological absolute.
In general, whenever you were taught something black-and-white with hard boundaries in high school science, they were probably oversimplifying.
[+] [-] Amorymeltzer|8 years ago|reply
The short version is that this definition only works for sexually reproducing species. The long version is that it doesn't work.
1: https://biology.stackexchange.com/q/39664/4101
[+] [-] adrianN|8 years ago|reply
[+] [-] Knufen|8 years ago|reply
[+] [-] jdavis703|8 years ago|reply
[+] [-] arxpoetica|8 years ago|reply
[+] [-] d0100|8 years ago|reply
[+] [-] fiatjaf|8 years ago|reply
I thought it was autonomous mutation plus natural selection.
[+] [-] rf15|8 years ago|reply
[+] [-] stefantalpalaru|8 years ago|reply
[deleted]
[+] [-] EGreg|8 years ago|reply
"We tend not to argue about what defines a species anymore, because that doesn't get you anywhere," said Prof Butlin. What he says is more interesting is understanding the role that hybridisation can have in the process of creating new species, which is why this observation of Galapagos finches is so important.
If you can't define what a species is, how can you talk about the process of creating new ones?
It seems they should be talking about the rate of gene flow between groups. "Genetically distinct" means very little because phenotypes can vary widely and still interbreed. Look at dogs, for example.
I would like to see more examples of allopatric speciation or other speciation. What they have here so far is reduced gene flow to a group of finches. Proving that none of them CAN interbreed with females is not so easy, as anecdotal evidence of females not recognizing songs of males doesn't cut it.
It's a bit like proving that an animal species has truly homosexual individuals. None of them do (except possibly for domesticated sheep) -- in fact the theory of evolution would predict that homosexuality would greatly reduce fitness, but there COULD be some members that are lifelong homosexuals, same as beta wolves etc. However to PROVE that an organism is exclusively homosexual they would need to carefuly watch it and all its pairings, however brief, its whole life.
Now, with species, you have to watch EVERY male with EVERY female around it, and vice versa. That is a huge undertaking and I doubt they did it here.
All they observed is phenotypical differences. And they haven't really explained how this is different from eg dogs, except to say that the females THEY SAW did not prefer the males' songs. Certainly this shows reduced gene flow due to preferences but not that they aren't interfertile. This is much different than a cat and a dog for example.
What I am ultimately trying to say is, I am quite skeptical that we have discovered ALL the means by which speciation occurs.
You can be a creationist or whatever else you'd like to be at this point. We barely understand how speciation really takes place, in the end we still only have theories.
I have read Lee Spetner's book "Not by Chance" which goes into the mathematics of speciation occurring exclusively by random mutation and natural selection. And it is astronomically improbable on its own terms.
This there HAVE to be forcing processes from the outside which we don't know about yet. We only guess into what they could be.
And on a related note, using evolution to explain behaviors and traits is like a religion, full of "just so" stories, in fields such as evolutionary psychology but also to explain pretty much ANY trait in a genetic fitness framework.
These "just so" stories are so pervasive yet smack of a notoriously unscientific practice and framework. All one has to do is concoct a possible way by which a trait (proto-wings, homosexuality, men becoming sleepy after an orgasm -- anything really) might confer some advantage. And the other way, such "just so" stories are used to "explain" the presence of certain traits as "the evolution of those traits" via totally untestable stories about the past.