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>Humans have not really had enough time as independent populations to diverge much There is no scientific basis for that claim. Many other animals have diverg

>Humans have not really had enough time as independent populations to diverge much There is no scientific basis for that claim. Many other animals have diverged less, in less time and are still separate subspecies. >African > Eurasia had regular exchanges as they where within relatively short walking distances. Interbreeding does not mean subspecies don't exist. Coyotes and wolves are totally separate species and they interbreed. This does not make them the same species, much less the same subspecies. Or the very example given in the article: polar bears and brown bears. Separate species, overlapping geographical regions, crossbreeding occurs in the overlap. Or again from the article example: giraffes. Also note they talk about the genetic distance, but the genetic distance between a west african and an australian aboriginal is greater than the difference between wolves and dogs, which are subspecies. Again, by all measures we use for wild animals, humans consist of several subspecies at least.

louhike 10y ago
The thing is we're talking about species here, not subspecies.
- MustardTiger 10y ago
  If you pay attention, we're talking about both. My replies have all very clearly been about subspecies, read my first post.
Retric 10y ago
Genetically Brown and polar bears are subspecies not separate species. They have also had 3+X as many generations since the last ice age vs people.
- MustardTiger 10y ago
  People have been separated far longer than just since the ice age. And no, some people think brown bears and polar bears should be reclassified, others do not. As it stands, they are separate species. Take the 2 seconds to google basic information before posting incorrect things that are so easy to verify. Even if you reclassify them, it still supports my point: humans consist of several subspecies.
  - Retric 10y ago
    People also talk about Europe and Asia as separate despite being a contiguous landmass on the same plate. Genetically brown and polar bears can and in reality often do interbreed producing viable offspring and exchanging genetic information between populations.
    - MustardTiger 10y ago
      >People also talk about Europe and Asia as separate despite being a contiguous landmass on the same plate That analogy is not useful at all. Continents are not biological organisms. >Genetically brown and polar bears can and in reality often do interbreed producing viable offspring and exchanging genetic information between populations And yet they are separate species. Just like the 4 separate species of giraffe the article is about, which can and do all interbreed. The concept of species is in no way reliant on an inability to produce fertile offspring.
      - Retric 10y ago
        The point which is very clear that people stick with old definitions despite new evidence even in the sciences. The great thing is different countries use different definitions yet people seem to assume whatever they grew up with is correct. https://en.wikipedia.org/wiki/Continent#/media/File:Continental_models-Australia.gif https://en.wikipedia.org/wiki/Continent#/media/File:Continen... At most you can say brown and polar bears are "generally classified as separate species" But, there really is debate on this topic.
        MustardTiger 10y ago
        So all those posts were just to say nothing?
  - deleted 10y ago
    [deleted]
- dalke 10y ago
  They are "generally classified as separate species", says https://en.wikipedia.org/wiki/Polar_bear#Taxonomy_and_evolution https://en.wikipedia.org/wiki/Polar_bear#Taxonomy_and_evolut... : > A comparison of the nuclear genome of polar bears with that of brown bears revealed a different pattern, the two forming genetically distinct clades that diverged approximately 603,000 years ago,[25] although the latest research is based on analysis of the complete genomes (rather than just the mitochondria or partial nuclear genomes) of polar and brown bears, and establishes the divergence of polar and brown bears at 400,000 years ago. > ... However, because neither species can survive long in the other's ecological niche, and because they have different morphology, metabolism, social and feeding behaviours, and other phenotypic characteristics, the two bears are generally classified as separate species.[29]
  - Retric 10y ago
    Most brown bears have about 2 percent genetic material from polar bears, but one population, the ABC Islands bears has between 5 percent and 10 percent polar bear genes, indicating more frequent and recent mating. Ed: I don't disagree with what you're saying, I just don't think it's relevant to discussions of DNA. We can call Pluto a potato, does not change anything. As to classification the trend is clearly to call them the same species we just need to let the old scientists die off ;)
    - MustardTiger 10y ago
      What you quoted supports his rebuttal, not your claim. You are completely backwards, the trend is away from that. The myth that interbreeding makes them the same species was never accurate, but it is completely unused in modern times. For example, the very article that started this discussion saying that giraffes are 4 species not one. We classify them as such based on DNA evidence. The fact that all 4 species can produce fertile offspring when cross breeding is not relevant at all.
      - Retric 10y ago
        The long term definition was more or less 'A group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding.' This brings up the arguably semantic idea that physical separation is enough even if they are still genetically compatible. So, in theory you can have genetically compatible separate species as soon as they are no longer capable of interbreeding. However, as Humans and Brown bares are both biologically capable of interbreeding and live in such a manner that the do interbreed they don't fit that definition. Temporary barriers are not necessarily enough as they may exchange DNA in the future. PS: Ring species are considered a single species because a mutation can start at one end and given time make it's way around the ring. Thus they are a single pool that can and will exchange DNA.

louhike 10y ago

The thing is we're talking about species here, not subspecies.

MustardTiger 10y ago
If you pay attention, we're talking about both. My replies have all very clearly been about subspecies, read my first post.

Retric 10y ago

Genetically Brown and polar bears are subspecies not separate species. They have also had 3+X as many generations since the last ice age vs people.

MustardTiger 10y ago
People have been separated far longer than just since the ice age. And no, some people think brown bears and polar bears should be reclassified, others do not. As it stands, they are separate species. Take the 2 seconds to google basic information before posting incorrect things that are so easy to verify. Even if you reclassify them, it still supports my point: humans consist of several subspecies.
- Retric 10y ago
  People also talk about Europe and Asia as separate despite being a contiguous landmass on the same plate. Genetically brown and polar bears can and in reality often do interbreed producing viable offspring and exchanging genetic information between populations.
  - MustardTiger 10y ago
    >People also talk about Europe and Asia as separate despite being a contiguous landmass on the same plate That analogy is not useful at all. Continents are not biological organisms. >Genetically brown and polar bears can and in reality often do interbreed producing viable offspring and exchanging genetic information between populations And yet they are separate species. Just like the 4 separate species of giraffe the article is about, which can and do all interbreed. The concept of species is in no way reliant on an inability to produce fertile offspring.
    - Retric 10y ago
      The point which is very clear that people stick with old definitions despite new evidence even in the sciences. The great thing is different countries use different definitions yet people seem to assume whatever they grew up with is correct. https://en.wikipedia.org/wiki/Continent#/media/File:Continental_models-Australia.gif https://en.wikipedia.org/wiki/Continent#/media/File:Continen... At most you can say brown and polar bears are "generally classified as separate species" But, there really is debate on this topic.
      - MustardTiger 10y ago
        So all those posts were just to say nothing?
- deleted 10y ago
  [deleted]
dalke 10y ago
They are "generally classified as separate species", says https://en.wikipedia.org/wiki/Polar_bear#Taxonomy_and_evolution https://en.wikipedia.org/wiki/Polar_bear#Taxonomy_and_evolut... : > A comparison of the nuclear genome of polar bears with that of brown bears revealed a different pattern, the two forming genetically distinct clades that diverged approximately 603,000 years ago,[25] although the latest research is based on analysis of the complete genomes (rather than just the mitochondria or partial nuclear genomes) of polar and brown bears, and establishes the divergence of polar and brown bears at 400,000 years ago. > ... However, because neither species can survive long in the other's ecological niche, and because they have different morphology, metabolism, social and feeding behaviours, and other phenotypic characteristics, the two bears are generally classified as separate species.[29]
- Retric 10y ago
  Most brown bears have about 2 percent genetic material from polar bears, but one population, the ABC Islands bears has between 5 percent and 10 percent polar bear genes, indicating more frequent and recent mating. Ed: I don't disagree with what you're saying, I just don't think it's relevant to discussions of DNA. We can call Pluto a potato, does not change anything. As to classification the trend is clearly to call them the same species we just need to let the old scientists die off ;)
  - MustardTiger 10y ago
    What you quoted supports his rebuttal, not your claim. You are completely backwards, the trend is away from that. The myth that interbreeding makes them the same species was never accurate, but it is completely unused in modern times. For example, the very article that started this discussion saying that giraffes are 4 species not one. We classify them as such based on DNA evidence. The fact that all 4 species can produce fertile offspring when cross breeding is not relevant at all.
    - Retric 10y ago
      The long term definition was more or less 'A group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding.' This brings up the arguably semantic idea that physical separation is enough even if they are still genetically compatible. So, in theory you can have genetically compatible separate species as soon as they are no longer capable of interbreeding. However, as Humans and Brown bares are both biologically capable of interbreeding and live in such a manner that the do interbreed they don't fit that definition. Temporary barriers are not necessarily enough as they may exchange DNA in the future. PS: Ring species are considered a single species because a mutation can start at one end and given time make it's way around the ring. Thus they are a single pool that can and will exchange DNA.