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The quoted statement should be interpreted in the context of the study. Specifically, in the context that "species’ current ranges are not always delineated by

• MustardTiger 10y ago
  The context does not contradict that statement. Every single measure used on every other animal would at minimum place humans in several subspecies. But we do not apply the same standards to ourselves for political reasons.
  • Retric 10y ago
    Humans have not really had enough time as independent populations to diverge much. The north american land bridge disappeared ~14,500 years ago so only ~14,000 years as separate populations. African > Eurasia had regular exchanges as they where within relatively short walking distances.
    • MustardTiger 10y ago
      >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.
    • dogma1138 10y ago
      That's not true we've seen speciation happening in front of our eyes with some species. While time is a factor 14,000 is more than enough for humans to speciate, the reason why this hasn't happened to humans is something that is actually a subject of research today.
      • Retric 10y ago
        Humans have a long reproductive cycle, so that's under 1,000 generations. For comparison bacteria can reach 1,000 generations in ideal conditions in less than 1 year.
        • dogma1138 10y ago
          We've had documented cases of speciation of various types of animals within only a few generations, birds for example tend to do that rather quickly as well as rapidly form ring species. And this isn't because birds are special but because they tend to migrate, in other cases natural or manmade barriers that split a species into distinct groups have also causes speciation after only a handful of generations. Besides birds where it's common due to migration patterns "man caused" rapid speciation has also been observed in rodents (squirrels/mice) and various types of fish. http://evolution.berkeley.edu/evolibrary/news/100201_speciation http://evolution.berkeley.edu/evolibrary/news/100201_speciat... You do not need a 1000 generations to speciate.
          • dalke 10y ago
            The first description in what you pointed to says "could signify the beginning of a speciation event". It doesn't say the result is a new species. The second description concerns a pairing between two hybrids which started a new lineage. It uses the term "lineage" instead of saying there is a new species. > These two examples make it clear that the division between species is not a black-and-white issue. Rather, speciation occurs as many different sorts of traits (physical, behavioral, and genetic) diverge from one another along a continuum. Because of this, biologists sometimes disagree about where to draw the line between incipient species — about when a division has become deep enough to warrant a new species name. Whatever we choose to call them, these two cases clearly illustrate how a lineage can split and begin to make its way down two separate evolutionary paths. Regarding ring species, https://en.wikipedia.org/wiki/Ring_species https://en.wikipedia.org/wiki/Ring_species says "Currently, there are four known forms of life that appear to match the definition of a ring species". Frankly, I thought there were more. It would suggest that birds don't tend to rapidly form ring species. > You do not need a 1000 generations to speciate. Are either of those two cases described in the literature as a new species, or are they given as a subspecies, or variant, or fertile hybrid, or some other term?
    • adekok 10y ago
      > ~14,000 years as separate populations. Perhaps even less. http://www.andrewcollins.com/page/articles/romanbust.htm http://www.andrewcollins.com/page/articles/romanbust.htm There was at least some contact between North America and Europe, close to 2K years ago.
      • Retric 10y ago
        The baring strait is also only 51 miles so there was likely quite a bit of accidental crossings if nothing else. For comparison Australia was populated around 65,000 to 75,000 years ago and that takes more than 200 miles by sea.
        • danieltillett 10y ago
          I don't think there is any good evidence for Australia being populated before 45,000 years ago. Modern humans hadn't even left Africa 75,000 years ago.
          • Retric 10y ago
            Your dates for leaving Africa seem to be off base. Homo sapiens ventured out of Africa around 100,000 years ago https://en.wikipedia.org/wiki/Early_human_migrations https://en.wikipedia.org/wiki/Early_human_migrations There where early tool across Afro-Eurasia as far back as 1.7 to 2.6 million years. Early human ancestors may have maintained separate populations spreading genetic mutations between them with occasional waves of migration displacing existing populations. Supporting the first idea is the wide range of habitat giving advantages to prior populations who are better able to cope with existing conditions. http://www.nature.com/news/teeth-from-china-reveal-early-human-trek-out-of-africa-1.18566 http://www.nature.com/news/teeth-from-china-reveal-early-hum... There really does not seem to be much evidence to tell one way or another.
            • danieltillett 10y ago
              The data regarding the early venturing out of Africa is not good, but even the wiki article says humans reached Australia 46,000 years ago.
  • dalke 10y ago
    The paper is about species, not subspecies. The paper says: > Thus, population genetic, phylogenetic, and network analyses of nuclear sequences demonstrate that the giraffe is genetically well structured into four distinct species. This is consistent with divergence times of 1.25 to 2 million years ago (mya) among the four clusters (Figure 3C). That genetic isolation is 100x longer than the human migration to the Americas. It's also 10x longer than the time to "Mitochondrial Eve" and about 8x longer than to "Y-chromosomal Adam". Humans do not meet the phylogenetic criteria which justifies the use of "subspecies". See http://www.nature.com/ng/journal/v36/n11s/full/ng1455.html http://www.nature.com/ng/journal/v36/n11s/full/ng1455.html and many others. Quoting that reference: > Modern human genetic variation does not structure into phylogenetic subspecies (geographical 'races'), nor do the taxa from the most common racial classifications of classical anthropology qualify as 'races' (Box 1). The social or ethnoancestral groups of the US and Latin America are not 'races', and it has not been demonstrated that any human breeding population is sufficiently divergent to be taxonomically recognized by the standards of modern molecular systematics. These observations are not to be taken as statements against doing research on demographic groups or populations. They only support a brief for linguistic precision and careful descriptions of groups under study. Terms and labels have qualitative implications.
    • MustardTiger 10y ago
      >The paper is about species, not subspecies. And my reply is about subspecies, and our refusal to apply the same standards we apply to other animals to ourselves. I do not understand your confusion. >Humans do not meet the phylogenetic criteria which justifies the use of "subspecies" We have greater genetic difference between races than ANY example of subspecies in existence. I am very aware that a large group of people have a political agenda in denying this fact. But no amount of "we can get rid of racism by pretending races don't exist" will change basic facts. DNA does not lie.
      • dalke 10y ago
        Yes, my complaint is that you are highjacking an article on species differentiation in giraffes to talk about purported human subspecies. No, we emphatically do not have that high of a genetic difference. Quite the opposite. The diversity in human genetics is relatively small compared to other species. For example, quoting http://www.nature.com/ng/journal/v27/n2/full/ng0201_155.html http://www.nature.com/ng/journal/v27/n2/full/ng0201_155.html : > The extent of DNA sequence variation of chimpanzees is several-fold greater than that of humans[1]. It is unclear, however, if humans or chimpanzees are exceptional among primates in having low and high amounts of DNA sequence diversity, respectively. To address this, we have determined approximately 10,000 bp of noncoding DNA sequences at Xq13.3 (which has been extensively studied in both humans and chimpanzees[1, 2]) from 10 western lowland gorillas (Gorilla gorilla gorilla) and 1 mountain gorilla (Gorilla gorilla beringei; that is, from 2 of the 3 currently recognized gorilla subspecies[3]), as well as 8 Bornean (Pongo pygmaeus pygmaeus) and 6 Sumatran (Pongo pygmaeus abelii) orang-utans, representing both currently recognized orang-utan subspecies[4]. We show that humans differ from the great apes in having a low level of genetic variation and a signal of population expansion. I'll repeat that last line for emphasis: "humans differ from the great apes in having a low level of genetic variation" The paper I linked to previously specifically compares the differences in DNA between chimpanzee subspecies to any putative human subspecies. > We know that there is human geographical variation, but does this infraspecific diversity reach a threshold that merits the designation 'subspecies', as is true with chimpanzees[14]? ... > The within- to between-group variation is very high for genetic polymorphisms (approx85%; refs. 16,17). This means that individuals from one 'race' may be overall more similar to individuals in one of the other 'races' than to other individuals in the same 'race'. This observation is perhaps insufficient[18], although it still is convincing because it illustrates the lack of a boundary. Coalescence times[19, 20] calculated from various genes suggest that the differentiation of modern humans began in Africa in populations whose morphological traits are unknown; it cannot be assumed from an evolutionary perspective that the traits used to define 'races' emerged simultaneously with this divergence[15]. There was no demonstrable 'racial' divergence. ... > Race' is a legitimate taxonomic concept that works for chimpanzees but does not apply to humans (at this time). The nonexistence of 'races' or subspecies in modern humans does not preclude substantial genetic variation that may be localized to regions or populations. DNA doesn't lie. Humans lie, or are mistaken. Please demonstrate that you are not mistaken, and tell us the source of your statement that "We have greater genetic difference between races than ANY example of subspecies in existence". What are the two most distinct human subspecies, and what is their level of DNA similarity? How does that compare to the difference in chimp subspecies?