8 ms·

I don't know if this is appropriate, but why are extinct humans classified as different species while the still alive humans are all considered the same species

by hasenj 10y ago

I don't know if this is appropriate, but why are extinct humans classified as different species while the still alive humans are all considered the same species? It seems political. Either some of the current races are different species, or the so called extinct human species are just different races.

athesyn 10y ago
Pretty sure it's the latter
woodruffw 10y ago
"Extinct humans" are not humans. They're homo, not homo sapiens (or, more strictly, homo sapiens sapiens). The genetic differences between you and any other human being of any other race are vanishingly small both in proportion to the size of the human genome and to the (known) differences between sapiens and neanderthalensis. It's not politics, it's parsimony.
- hasenj 10y ago
  Your answer gives no explanation beyond "because they are not humans". How do you know that?
  - simonh 10y ago
    Because we have extensive samples of the Neanderthal genome extracted from bone fragments, and before that from morphological studies of the Neanderthal skeleton which display far greater differences from humans than any differences in skeletons between human races. Even 18th Century observers were able to see that. Yes there is no one universally agreed definition of species, but Neanderthals were vastly more different from living humans than and differences between living human populations.
    - ptaipale 10y ago
      BTW is there a good comparison for how big the anatomical differences are between Neanderthals and modern Europeans, compared to the differences between modern Europeans and modern, significantly distinct populations such as Congo pygmies? https://en.wikipedia.org/wiki/Congo_Pygmies https://en.wikipedia.org/wiki/Congo_Pygmies (Anatomic differences are perhaps not as important as cognitive and psychological differences, but the latter are very hard to find out about extinct populations.)
- ascotan 10y ago
  True they are genetically different but that's not the definition of a 'species'. There is a level of politics in biology over what constitutes a species and what does not. Technically a 'species' is something that interbreeds but does not breed with members outside of it's species and mating produces reproductive offspring. (at least this is the old mayr definition that everyone uses) The problem is that neanderthals and humans matings produced viable offspring. So is 'neanderthal' a species or not? The same issue is a problem with the Galapagos finches, which are the holy cows of darwinian genetics. By Mayr's definition they should not be able to interbred and produce viable offspring. However, apparently they can interbreed and therefore are not technically different species. No one in science want's to badmouth the masters, so Darwin's theory of Galapagos finch species will quietly be put back in the Victorian cabinet while we invent a new 'genetics' based theory of 'species' that makes everyone happy. However, life is not easily classified. Viruses? Species? Bacterial plasmid replication? There is a lot of politics in the life sciences. Naming a new species or having your name on a species is a big deal. It reminds me of Cope/Marsh and the dinosaur finds (https://en.wikipedia.org/wiki/Bone_Wars https://en.wikipedia.org/wiki/Bone_Wars) of the early 20th century. They both screwed up the identification of many species so that they could out publish the other and left the mess for future scientists to clean up. My feelings on this is that we still don't have enough evidence about the genetic makeup of humans to really make any conclusions on anything. Example: What is the blood type in the reference sequence for the human genome?? We know that there is A, B, A/B and O which represent 4 different genotypes (an AA sequence, a BB sequence, an AB sequence and a missing sequence from both alleles). If I sequence a neatherthal with blood type A and a human with blood type O, are we genetically divergent?? How can you come to this conclusion unless you know the plasticity of each genome. (i.e. I can't identify a nucleotide change in blood type gene for a type O human because the gene is absent) It looks like most of the research has been on mtDNA which is passed from mother to child. If we can't find a mtDNA match, it might just mean that there is no maternal linage that can be traced back to that sequenced individual. (i.e. all the children of that mother died out at some point) Different species? That's a question for politics imho. I personally think that life shuns classification. BTW sorry for the ramble :0
  - simonh 10y ago
    Then you have ring species[1] that blow a nice big hole in the interbreeding based definitions of species. Species and race are vague terms we use for convenience. That's all. I think keeping them vaguely defined is a feature not a bug, because it could help prevent people assigning too much weight or meaning to them. If people get the idea that race and species can be precisely defined, then maybe they can be measured? Maybe we can use that to derive tests or policies? But trying to precisely define race and species is futile, like trying to put light in a box. I'd rather knowingly and consciously keep the ambiguity, to remind myself that the terminology isn't the reality. [1] https://en.wikipedia.org/wiki/Ring_species https://en.wikipedia.org/wiki/Ring_species
- dghf 10y ago
  Sapiens by Yuval Harari defines "human" as "any member of the genus Homo". I don't know how common or accepted this definition is. It could become problematic if, as has been suggested, some or all of the other great apes are reclassified as Homo rather than Pan, Gorilla or Pongo.
  - gus_massa 10y ago
    I think that this is the usual definition of "human", but I also think that it doesn't agree with the layman definition of "human". https://en.wikipedia.org/wiki/Human https://en.wikipedia.org/wiki/Human For a layman, an "human" is a "modern human", i.e. "Homo sapiens sapiens", i.e. me. There are two difficult problems here. The first is how to classify animals species (including humans, whatever it means). The taxonomy classification is somewhat arbitrary. It's very useful for discussions between biologist, but arbitrary. For an easy example, what is a kingdom looks like an easy question, but https://en.wikipedia.org/wiki/Kingdom_(biology)#Summary https://en.wikipedia.org/wiki/Kingdom_(biology)#Summary Currently Homo, Pan, Gorilla or Pongo are different "genus" of the Hominidae "family". (I hope I got all the notation correctly.) The genus is somewhat special, because it's written in the name of the specie, but we could have agree to write the family in the name two. We could have been "H. H. sapiens sapiens" and chimps could be "H. P. troglodytes" The second problem is that we all agree that the sentence for killing a "human" should be different of the sentence for killing a cow or a pig. But the decision of what "human" means in that sentence is a political one, not a scientific one. Should we consider killing any great apes as bad as killing me? What about other apes? Why? Why must we use the taxonomy classification? What about whales and dolphins? Octopus?
    - TeMPOraL 10y ago
      > We could have been "H. H. sapiens sapiens" and chimps could be "H. P. troglodytes" Tangent, but if we ever genetically engineer some eldritch horrors, I vote to classify them as "H. P. lovecraft".
      - eliasbagley 10y ago
        There's a traditional of using Latin names for species classification, so maybe H. P. Lovecraftus
Bamberg 10y ago
"A species is often defined as the largest group of organisms in which two individuals can produce fertile offspring, typically by sexual reproduction."[1] As far as I know there is no evidence that neanderthal females could produce fertile offspring with a male homo sapiens -- but only the other way round. [1] https://en.wikipedia.org/wiki/Species https://en.wikipedia.org/wiki/Species
- hasenj 10y ago
  Is there evidence that they could not?
- fanpuns 10y ago
  Here's a study that finds that the inverse was actually impossible/exceedingly unlikely (homo sapien females carrying neanderthal male babies). This outside of my field, but wouldn't that mean then that it would have to be neanderthal females carrying male homo sapien's babies in order for the genomic remnants to be observable? http://www.sciencemag.org/news/2016/04/modern-human-females-and-male-neandertals-had-trouble-making-babies-here-s-why http://www.sciencemag.org/news/2016/04/modern-human-females-...
  - mlonkibjuyhv 10y ago
    Heh, funny how easy it is to assume that male brutes raped our women.
    - Girlang 10y ago
      Exactly! We all have to carry the third-wave-feminist party line here.
  - ZeroGravitas 10y ago
    The study seems to suggest only babies that were themeselves male would have trouble making it to birth. So female babies being born to homo sapiens mothers would still be half-neaderthal, they just wouldn't have Y chromosomes which is what the study was tracing ancestry through.
thesagan 10y ago
I think it's an honest question, even though it's controversial and attracts downvotes. (I noticed your question is in gray right now.) In my mind, it's a question of a "big enough difference" in a day-to-day-like mode of thinking. Since I'm not a biologist I'm only using my own version of how I think of it. I personally think of the concept of species, etc., as "shades of gray" that change depending on the lighting. (If that makes sense.) Look at the huge differences in dog breeds, for example. If I didn't know better I would think some dogs are a completely different class of animal when compared. (Think chiwawas and german shepherds, in their visual appearance.) Sometimes I think of my dog as a person. Other times, not so much. Is it political? I think some people could make some sort of (weak) argument for that; in how I allocate resources to my dog, and why I do it. Why I even keep a dog around. Also depends on how you'd define politics; how broadly and deeply. In this case I think your question it's a very interesting one, if we were to imagine running into a fresh population of neanderthals I bet there would be political ramifications between groups!
- rangibaby 10y ago
  Although they look different any breed of dog could do it doggy style and make another dog that could make more dogs.
  - Al-Khwarizmi 10y ago
    This is often said, but can really a St Bernard and a Yorkshire Terrier do that?
    - BjoernKW 10y ago
      Yes, absolutely. Dogs can really get creative. I know of Alsatian / dachshund mixes. Not quite as extreme but still makes you wonder.
      - ptaipale 10y ago
        Some breed combinations cannot necessarily give birth even if pregnancy can start. In fact also some pure breeds cannot give birth except by Cesarean section.
BjoernKW 10y ago
As a layman my go-to definition of a species used to be the one given by Bamberg below (and for all practical purposes it still makes sense). Modern human races can interbreed and have fertile offspring. Therefore they don't constitute different species. It turns out the concept of species is dated or at least doesn't fit all the phenomena out there: http://biology.stackexchange.com/questions/39664/how-could-humans-have-interbred-with-neanderthals-if-were-a-different-species http://biology.stackexchange.com/questions/39664/how-could-h... So, I suppose one could argue to some extent that Neanderthals were a human race rather than a species of their own.
lucasnemeth 10y ago
Race is a social construct, there's no biological explanation for race. The set of characteristics that are identified with different races are social constructs, those clusters of features does not correlate to a significant difference in biological terms. Genetic methods do not support or explain the classification of humans into discrete races. Races are not genetically homogenous and lack clear-cut genetic boundaries. Two people from different races can be way more similar genetically than two people from the same race. The concept of race was built over a long story of separating humanity in different ethnic groups, and then physical characteristics of some of those ethnic groups started slowing being adopted as a mean to show that those people are intrinsically different, but they are just an unimportant set of characteristics that does not convey important information from a genetic perspective, they gained social meaning through culture. The modern concept of race took form in the enlightenment, https://twitter.com/Limerick1914/status/757227361582608384 https://twitter.com/Limerick1914/status/757227361582608384, when the original western notion of which ethnic groups exists in the world was built into a racist anthropology. That doesn't mean that "all lives matter" or we shouldn't talk about race. Race is a social construct, and as a social construct, it exists. Money is also a social construct. But, the concept of race makes no sense besides the social structure that was built on. That why different countries consider that the set of existing races is different, for instance, the only country that really considers "latino" a race is the US. Going back to your question, the extinct humans actually had important biological differences, the different races have not.
- hasenj 10y ago
  Honestly, I think calling something "a social construct" is meaningless political rhetoric. If humans and Neanderthals interbreed for a long enough period without annhiliating each other through war, wouldn't their offspring converge over time? Some ethnicities are more susceptible to certain diseases. Is that a social construct?
  - scatters 10y ago
    Poor people are more susceptible to certain diseases than rich people. That doesn't stop money being a social construct.

by hasenj 10y ago

athesyn 10y ago

Pretty sure it's the latter

woodruffw 10y ago

"Extinct humans" are not humans. They're homo, not homo sapiens (or, more strictly, homo sapiens sapiens). The genetic differences between you and any other human being of any other race are vanishingly small both in proportion to the size of the human genome and to the (known) differences between sapiens and neanderthalensis. It's not politics, it's parsimony.

hasenj 10y ago
Your answer gives no explanation beyond "because they are not humans". How do you know that?
- simonh 10y ago
  Because we have extensive samples of the Neanderthal genome extracted from bone fragments, and before that from morphological studies of the Neanderthal skeleton which display far greater differences from humans than any differences in skeletons between human races. Even 18th Century observers were able to see that. Yes there is no one universally agreed definition of species, but Neanderthals were vastly more different from living humans than and differences between living human populations.
  - ptaipale 10y ago
    BTW is there a good comparison for how big the anatomical differences are between Neanderthals and modern Europeans, compared to the differences between modern Europeans and modern, significantly distinct populations such as Congo pygmies? https://en.wikipedia.org/wiki/Congo_Pygmies https://en.wikipedia.org/wiki/Congo_Pygmies (Anatomic differences are perhaps not as important as cognitive and psychological differences, but the latter are very hard to find out about extinct populations.)
ascotan 10y ago
True they are genetically different but that's not the definition of a 'species'. There is a level of politics in biology over what constitutes a species and what does not. Technically a 'species' is something that interbreeds but does not breed with members outside of it's species and mating produces reproductive offspring. (at least this is the old mayr definition that everyone uses) The problem is that neanderthals and humans matings produced viable offspring. So is 'neanderthal' a species or not? The same issue is a problem with the Galapagos finches, which are the holy cows of darwinian genetics. By Mayr's definition they should not be able to interbred and produce viable offspring. However, apparently they can interbreed and therefore are not technically different species. No one in science want's to badmouth the masters, so Darwin's theory of Galapagos finch species will quietly be put back in the Victorian cabinet while we invent a new 'genetics' based theory of 'species' that makes everyone happy. However, life is not easily classified. Viruses? Species? Bacterial plasmid replication? There is a lot of politics in the life sciences. Naming a new species or having your name on a species is a big deal. It reminds me of Cope/Marsh and the dinosaur finds (https://en.wikipedia.org/wiki/Bone_Wars https://en.wikipedia.org/wiki/Bone_Wars) of the early 20th century. They both screwed up the identification of many species so that they could out publish the other and left the mess for future scientists to clean up. My feelings on this is that we still don't have enough evidence about the genetic makeup of humans to really make any conclusions on anything. Example: What is the blood type in the reference sequence for the human genome?? We know that there is A, B, A/B and O which represent 4 different genotypes (an AA sequence, a BB sequence, an AB sequence and a missing sequence from both alleles). If I sequence a neatherthal with blood type A and a human with blood type O, are we genetically divergent?? How can you come to this conclusion unless you know the plasticity of each genome. (i.e. I can't identify a nucleotide change in blood type gene for a type O human because the gene is absent) It looks like most of the research has been on mtDNA which is passed from mother to child. If we can't find a mtDNA match, it might just mean that there is no maternal linage that can be traced back to that sequenced individual. (i.e. all the children of that mother died out at some point) Different species? That's a question for politics imho. I personally think that life shuns classification. BTW sorry for the ramble :0
- simonh 10y ago
  Then you have ring species[1] that blow a nice big hole in the interbreeding based definitions of species. Species and race are vague terms we use for convenience. That's all. I think keeping them vaguely defined is a feature not a bug, because it could help prevent people assigning too much weight or meaning to them. If people get the idea that race and species can be precisely defined, then maybe they can be measured? Maybe we can use that to derive tests or policies? But trying to precisely define race and species is futile, like trying to put light in a box. I'd rather knowingly and consciously keep the ambiguity, to remind myself that the terminology isn't the reality. [1] https://en.wikipedia.org/wiki/Ring_species https://en.wikipedia.org/wiki/Ring_species
dghf 10y ago
Sapiens by Yuval Harari defines "human" as "any member of the genus Homo". I don't know how common or accepted this definition is. It could become problematic if, as has been suggested, some or all of the other great apes are reclassified as Homo rather than Pan, Gorilla or Pongo.
- gus_massa 10y ago
  I think that this is the usual definition of "human", but I also think that it doesn't agree with the layman definition of "human". https://en.wikipedia.org/wiki/Human https://en.wikipedia.org/wiki/Human For a layman, an "human" is a "modern human", i.e. "Homo sapiens sapiens", i.e. me. There are two difficult problems here. The first is how to classify animals species (including humans, whatever it means). The taxonomy classification is somewhat arbitrary. It's very useful for discussions between biologist, but arbitrary. For an easy example, what is a kingdom looks like an easy question, but https://en.wikipedia.org/wiki/Kingdom_(biology)#Summary https://en.wikipedia.org/wiki/Kingdom_(biology)#Summary Currently Homo, Pan, Gorilla or Pongo are different "genus" of the Hominidae "family". (I hope I got all the notation correctly.) The genus is somewhat special, because it's written in the name of the specie, but we could have agree to write the family in the name two. We could have been "H. H. sapiens sapiens" and chimps could be "H. P. troglodytes" The second problem is that we all agree that the sentence for killing a "human" should be different of the sentence for killing a cow or a pig. But the decision of what "human" means in that sentence is a political one, not a scientific one. Should we consider killing any great apes as bad as killing me? What about other apes? Why? Why must we use the taxonomy classification? What about whales and dolphins? Octopus?
  - TeMPOraL 10y ago
    > We could have been "H. H. sapiens sapiens" and chimps could be "H. P. troglodytes" Tangent, but if we ever genetically engineer some eldritch horrors, I vote to classify them as "H. P. lovecraft".
    - eliasbagley 10y ago
      There's a traditional of using Latin names for species classification, so maybe H. P. Lovecraftus

Bamberg 10y ago

"A species is often defined as the largest group of organisms in which two individuals can produce fertile offspring, typically by sexual reproduction."[1] As far as I know there is no evidence that neanderthal females could produce fertile offspring with a male homo sapiens -- but only the other way round. [1] https://en.wikipedia.org/wiki/Species https://en.wikipedia.org/wiki/Species

hasenj 10y ago
Is there evidence that they could not?
fanpuns 10y ago
Here's a study that finds that the inverse was actually impossible/exceedingly unlikely (homo sapien females carrying neanderthal male babies). This outside of my field, but wouldn't that mean then that it would have to be neanderthal females carrying male homo sapien's babies in order for the genomic remnants to be observable? http://www.sciencemag.org/news/2016/04/modern-human-females-and-male-neandertals-had-trouble-making-babies-here-s-why http://www.sciencemag.org/news/2016/04/modern-human-females-...
- mlonkibjuyhv 10y ago
  Heh, funny how easy it is to assume that male brutes raped our women.
  - Girlang 10y ago
    Exactly! We all have to carry the third-wave-feminist party line here.
- ZeroGravitas 10y ago
  The study seems to suggest only babies that were themeselves male would have trouble making it to birth. So female babies being born to homo sapiens mothers would still be half-neaderthal, they just wouldn't have Y chromosomes which is what the study was tracing ancestry through.

thesagan 10y ago

I think it's an honest question, even though it's controversial and attracts downvotes. (I noticed your question is in gray right now.) In my mind, it's a question of a "big enough difference" in a day-to-day-like mode of thinking. Since I'm not a biologist I'm only using my own version of how I think of it. I personally think of the concept of species, etc., as "shades of gray" that change depending on the lighting. (If that makes sense.) Look at the huge differences in dog breeds, for example. If I didn't know better I would think some dogs are a completely different class of animal when compared. (Think chiwawas and german shepherds, in their visual appearance.) Sometimes I think of my dog as a person. Other times, not so much. Is it political? I think some people could make some sort of (weak) argument for that; in how I allocate resources to my dog, and why I do it. Why I even keep a dog around. Also depends on how you'd define politics; how broadly and deeply. In this case I think your question it's a very interesting one, if we were to imagine running into a fresh population of neanderthals I bet there would be political ramifications between groups!

rangibaby 10y ago
Although they look different any breed of dog could do it doggy style and make another dog that could make more dogs.
- Al-Khwarizmi 10y ago
  This is often said, but can really a St Bernard and a Yorkshire Terrier do that?
  - BjoernKW 10y ago
    Yes, absolutely. Dogs can really get creative. I know of Alsatian / dachshund mixes. Not quite as extreme but still makes you wonder.
    - ptaipale 10y ago
      Some breed combinations cannot necessarily give birth even if pregnancy can start. In fact also some pure breeds cannot give birth except by Cesarean section.

BjoernKW 10y ago

As a layman my go-to definition of a species used to be the one given by Bamberg below (and for all practical purposes it still makes sense). Modern human races can interbreed and have fertile offspring. Therefore they don't constitute different species. It turns out the concept of species is dated or at least doesn't fit all the phenomena out there: http://biology.stackexchange.com/questions/39664/how-could-humans-have-interbred-with-neanderthals-if-were-a-different-species http://biology.stackexchange.com/questions/39664/how-could-h... So, I suppose one could argue to some extent that Neanderthals were a human race rather than a species of their own.

lucasnemeth 10y ago

Race is a social construct, there's no biological explanation for race. The set of characteristics that are identified with different races are social constructs, those clusters of features does not correlate to a significant difference in biological terms. Genetic methods do not support or explain the classification of humans into discrete races. Races are not genetically homogenous and lack clear-cut genetic boundaries. Two people from different races can be way more similar genetically than two people from the same race. The concept of race was built over a long story of separating humanity in different ethnic groups, and then physical characteristics of some of those ethnic groups started slowing being adopted as a mean to show that those people are intrinsically different, but they are just an unimportant set of characteristics that does not convey important information from a genetic perspective, they gained social meaning through culture. The modern concept of race took form in the enlightenment, https://twitter.com/Limerick1914/status/757227361582608384 https://twitter.com/Limerick1914/status/757227361582608384, when the original western notion of which ethnic groups exists in the world was built into a racist anthropology. That doesn't mean that "all lives matter" or we shouldn't talk about race. Race is a social construct, and as a social construct, it exists. Money is also a social construct. But, the concept of race makes no sense besides the social structure that was built on. That why different countries consider that the set of existing races is different, for instance, the only country that really considers "latino" a race is the US. Going back to your question, the extinct humans actually had important biological differences, the different races have not.

hasenj 10y ago
Honestly, I think calling something "a social construct" is meaningless political rhetoric. If humans and Neanderthals interbreed for a long enough period without annhiliating each other through war, wouldn't their offspring converge over time? Some ethnicities are more susceptible to certain diseases. Is that a social construct?
- scatters 10y ago
  Poor people are more susceptible to certain diseases than rich people. That doesn't stop money being a social construct.