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I thought this article would also mention ring species, which is a species where geographically adjacent members can mate with each other, but sufficiently far-

I thought this article would also mention ring species, which is a species where geographically adjacent members can mate with each other, but sufficiently far-away members cannot. The "ring" occurs when the habitat goes around the globe and two "incompatible" populations meet. In isolation, they would be separate species, but considering the existence of the ring connecting them, they are deemed to be a single species. Gene flow can happen between the two incompatible populations through the ring connecting them. Of course, there is nothing preventing such a ring from having more than two ends, so there could potentially even be ring species with branches or further sub-rings coming off them. https://en.wikipedia.org/w/index.php?title=Ring_species https://en.wikipedia.org/w/index.php?title=Ring_species

hammock 4y ago
To picture the more complex “rings” I am mentally creating a paper snowflake with large chunks cut out of it, and then unfolding it
tantalor 4y ago
Neat, has this been reproduced in laboratory?
- pklausler 4y ago
  Observed in the wild (Larus gulls) as a ring species around (almost!) the Arctic. You can also make a good case that most species are "ring species" in the time dimension.
  - alanbernstein 4y ago
    E: ignore this I think that would require a modern species to be compatible with a direct ancestor from the distant past, with generations of incompatible beings in between. Otherwise there is no "ring". But that seems 1) unlikely, 2) untestable.
    - pklausler 4y ago
      The whole point of a "ring species" is that the ring isn't closed, and the individuals at its ends are not compatible mates.
      - dragonwriter 4y ago
        While the term applies more broadly, it's called a “ring” from geographic examples where the ring is closed geographically, with adjacent/overlapping incompatible populations, but where there is a literal ring of geography wherein adjacent populations interbreed continuously except the two adjacent incompatible ends.
      - alanbernstein 4y ago
        Whoops, I guess you're right. I read about ring species long ago and I definitely misunderstood the concept, so I'm glad you corrected that. I was thinking all neighbors are compatible, but incompatible with the opposite side. However, because of the impossibility of contact between the two temporal ends, I'm not sure what the value would be in thinking about a temporal ring species?
        pklausler 4y ago
        It's an analogy to help understand evolution over time in a lineage.
        mannykannot 4y ago
        The Wikipedia entry quotes Dawkins: The evolutionary biologist Richard Dawkins remarks that ring species "are only showing us in the spatial dimension something that must always happen in the time dimension".
        joshuaissac 4y ago
        The kind of ring species you refer to would also be possible, although far less likely. The ancestor species could form a geographical ring, and if the members are not too populous, nor too migratory, then mutations that cause local incompatibility would be selected out (because it makes it much harder to find a mate) whereas mutations that cause non-local incompatibility may persist (if the species is largely non-migratory, so non-local compatibility is not as valuable). Over time, the non-local incompatibilities can build up and create a ring species like the one you describe. But something like this is far less likely than a ring species with incompatible ends. Because such "complete" rings can decay into incomplete rings through the extinction of a connecting subspecies, and similarly, incomplete rings can segment further, and then grow again as two separate ring species. But a complete ring, once broken, is very unlikely to re-form.
  - irrational 4y ago
    Isn’t the human species a ring species?
deleted 4y ago
[deleted]
ErikCorry 4y ago
I wonder if there is something special about birds in the immediate post-Chicxulub period that makes the bird species hard to arrange in a tree. You might expect that the few surviving birds were rapidly diversifying into ecological niches that were vacant after the asteroid. The sorts of genetic changes that make interbreeding impossible might lag behind (Eg changes in numbers of chromosomes) since the frequency of such species-bifurcating events would be based on other mechanisms not related to available ecological niches. So perhaps there's a period in which birds that look completely different can still interbreed to a larger extent than now? It would be like ring species, but taken to an absurd degree. I'm kinda riffing without really knowing what I'm talking about, but imagine a world where birds of all shapes and sizes can interbreed and occasionally do so.
- 7952 4y ago
  Maybe certain genes facilitate a particular strategy to evolution. And part of an organisms phenotype makes the species evolve in a particular way that gives genes an advantage over successive species. Adapting to the evolutionary environment. And naively birds are different. They can fly great distances in a single lifetime and cross many different habitats. In the time dimension that is very different to a plant or a small mammal. Not sure if that actually makes a difference though over such long timescale. An insect family can spread across the world just like a bird can.
- cwmma 4y ago
  Sounds like "push of the past" [1] basically successful species often stem from a highly successful adaption so show intense diversification early on, like birds when they are suddenly the only flying species. 1. https://en.wikipedia.org/wiki/Push_of_the_past?wprov=sfla1 https://en.wikipedia.org/wiki/Push_of_the_past?wprov=sfla1
- Tao3300 4y ago
  I have a feeling it's the simple fact that most bird species can fly and many of those species migrate incredible distances. This means (1) bird populations spread out and (2) they face survival pressure across multiple ecosystems. Caveat emptor, that's just my layperson's "makes sense to me" hunch. No credentials or citations.

hammock 4y ago

To picture the more complex “rings” I am mentally creating a paper snowflake with large chunks cut out of it, and then unfolding it

tantalor 4y ago

Neat, has this been reproduced in laboratory?

pklausler 4y ago
Observed in the wild (Larus gulls) as a ring species around (almost!) the Arctic. You can also make a good case that most species are "ring species" in the time dimension.
- alanbernstein 4y ago
  E: ignore this I think that would require a modern species to be compatible with a direct ancestor from the distant past, with generations of incompatible beings in between. Otherwise there is no "ring". But that seems 1) unlikely, 2) untestable.
  - pklausler 4y ago
    The whole point of a "ring species" is that the ring isn't closed, and the individuals at its ends are not compatible mates.
    - dragonwriter 4y ago
      While the term applies more broadly, it's called a “ring” from geographic examples where the ring is closed geographically, with adjacent/overlapping incompatible populations, but where there is a literal ring of geography wherein adjacent populations interbreed continuously except the two adjacent incompatible ends.
    - alanbernstein 4y ago
      Whoops, I guess you're right. I read about ring species long ago and I definitely misunderstood the concept, so I'm glad you corrected that. I was thinking all neighbors are compatible, but incompatible with the opposite side. However, because of the impossibility of contact between the two temporal ends, I'm not sure what the value would be in thinking about a temporal ring species?
      - pklausler 4y ago
        It's an analogy to help understand evolution over time in a lineage.
        mannykannot 4y ago
        The Wikipedia entry quotes Dawkins: The evolutionary biologist Richard Dawkins remarks that ring species "are only showing us in the spatial dimension something that must always happen in the time dimension".
      - joshuaissac 4y ago
        The kind of ring species you refer to would also be possible, although far less likely. The ancestor species could form a geographical ring, and if the members are not too populous, nor too migratory, then mutations that cause local incompatibility would be selected out (because it makes it much harder to find a mate) whereas mutations that cause non-local incompatibility may persist (if the species is largely non-migratory, so non-local compatibility is not as valuable). Over time, the non-local incompatibilities can build up and create a ring species like the one you describe. But something like this is far less likely than a ring species with incompatible ends. Because such "complete" rings can decay into incomplete rings through the extinction of a connecting subspecies, and similarly, incomplete rings can segment further, and then grow again as two separate ring species. But a complete ring, once broken, is very unlikely to re-form.
- irrational 4y ago
  Isn’t the human species a ring species?

deleted 4y ago

[deleted]

ErikCorry 4y ago

I wonder if there is something special about birds in the immediate post-Chicxulub period that makes the bird species hard to arrange in a tree. You might expect that the few surviving birds were rapidly diversifying into ecological niches that were vacant after the asteroid. The sorts of genetic changes that make interbreeding impossible might lag behind (Eg changes in numbers of chromosomes) since the frequency of such species-bifurcating events would be based on other mechanisms not related to available ecological niches. So perhaps there's a period in which birds that look completely different can still interbreed to a larger extent than now? It would be like ring species, but taken to an absurd degree. I'm kinda riffing without really knowing what I'm talking about, but imagine a world where birds of all shapes and sizes can interbreed and occasionally do so.

7952 4y ago
Maybe certain genes facilitate a particular strategy to evolution. And part of an organisms phenotype makes the species evolve in a particular way that gives genes an advantage over successive species. Adapting to the evolutionary environment. And naively birds are different. They can fly great distances in a single lifetime and cross many different habitats. In the time dimension that is very different to a plant or a small mammal. Not sure if that actually makes a difference though over such long timescale. An insect family can spread across the world just like a bird can.
cwmma 4y ago
Sounds like "push of the past" [1] basically successful species often stem from a highly successful adaption so show intense diversification early on, like birds when they are suddenly the only flying species. 1. https://en.wikipedia.org/wiki/Push_of_the_past?wprov=sfla1 https://en.wikipedia.org/wiki/Push_of_the_past?wprov=sfla1
Tao3300 4y ago
I have a feeling it's the simple fact that most bird species can fly and many of those species migrate incredible distances. This means (1) bird populations spread out and (2) they face survival pressure across multiple ecosystems. Caveat emptor, that's just my layperson's "makes sense to me" hunch. No credentials or citations.