Ancient Stone Tool Find Suggests Mystery Human Species

a reply to: rickymouse

The genetic evidence is pretty convincing anyway.

originally posted by: Harte

originally posted by: Origyptian
reply to: SLAYER69

Do we know with certainty that this was a different "species", i.e., with a gene pool incapable of breeding with today's humans?

Inability to breed with another animal is not a species criterion.

Harte

Well, technically that's correct because there will always be "another animal" that can't breed with its species. But in terms of populations of organisms, speciation is defined by the ability to breed among the population.

So my question is whether the population responsible for those ancient stone tools can be considered a "species" that's different than today's h. sapiens. Otherwise, how do we know it's not just another race variant?

originally posted by: Origyptian

originally posted by: Harte

originally posted by: Origyptian
reply to: SLAYER69

Do we know with certainty that this was a different "species", i.e., with a gene pool incapable of breeding with today's humans?

Inability to breed with another animal is not a species criterion.

Harte

Well, technically that's correct because there will always be "another animal" that can't breed with its species. But in terms of populations of organisms, speciation is defined by the ability to breed among the population.

Actually, it's not.

originally posted by: OrigyptianSo my question is whether the population responsible for those ancient stone tools can be considered a "species" that's different than today's h. sapiens. Otherwise, how do we know it's not just another race variant?

We can't know this for certain unless remains can be found. However, the findings likely date to a period prior to the time H. Sapiens left Africa, as far as we know.

Given that a great many different species of Homo have been found all over the Eastern Hemisphere, it's reasonably safe to assume (for now) that these tools were created by a different species of Homo.

Harte

originally posted by: Origyptian
Well, technically that's correct because there will always be "another animal" that can't breed with its species. But in terms of populations of organisms, speciation is defined by the ability to breed among the population.

originally posted by: Harte
Actually, it's not.

Interesting. Then what is your definition of "species"?

originally posted by: Origyptian

Interesting. Then what is your definition of "species"?

I think you have it the wrong way round, you are defining species as a group incapable of breeding with a member of another taxonomy, when in fact a species is defined as a group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding with each other. your definition excludes any possibility of interbreeding, whereas the latter definition doesn't
Hybrids

originally posted by: Marduk

originally posted by: Origyptian

Interesting. Then what is your definition of "species"?

I think you have it the wrong way round, you are defining species as a group incapable of breeding with a member of another taxonomy, when in fact a species is defined as a group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding with each other. your definition excludes any possibility of interbreeding, whereas the latter definition doesn't
Hybrids

Thanks, I tried to clarify that in my most recent post. I didn't mean to "define" a species as "the incompatibility with a given gene pool". But such incompatibility between population gene pools is indeed a consequence of speciation.

And so my earlier point was simply is that if the Australian population wasn't capable of genetic recombination with modern humans, that would support the notion that it was a different species, but I know of no evidence to suggest it was a different species. Likewise for Neanderthal and Cro Magnon, for that matter. Why refer to them as different species rather than simply race variants?

originally posted by: Origyptian

originally posted by: Marduk

originally posted by: Origyptian

Interesting. Then what is your definition of "species"?

I think you have it the wrong way round, you are defining species as a group incapable of breeding with a member of another taxonomy, when in fact a species is defined as a group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding with each other. your definition excludes any possibility of interbreeding, whereas the latter definition doesn't
Hybrids

Thanks, I tried to clarify that in my most recent post. I didn't mean to "define" a species as "the incompatibility with a given gene pool". But such incompatibility between population gene pools is indeed a consequence of speciation.

Most of the time that is true, if geographical separation lasts long enough.

On the other hand:

A classic example of ring species was the Larus gulls' circumpolar species "ring". The range of these gulls forms a ring around the North Pole, which is not normally transited by individual gulls.

The European herring gull (L. argentatus argenteus), which lives primarily in Great Britain and Ireland, can hybridize with the American herring gull (L. smithsonianus), (living in North America), which can also hybridize with the Vega or East Siberian herring gull (L. vegae), the western subspecies of which, Birula's gull (L. vegae birulai), can hybridize with Heuglin's gull (L. heuglini), which in turn can hybridize with the Siberian lesser black-backed gull (L. fuscus). All four of these live across the north of Siberia. The last is the eastern representative of the lesser black-backed gulls back in north-western Europe, including Great Britain.

The lesser black-backed gulls and herring gulls are sufficiently different that they do not normally hybridize; thus the group of gulls forms a continuum except where the two lineages meet in Europe.

Wiki
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originally posted by: OrigyptianAnd so my earlier point was simply is that if the Australian population wasn't capable of genetic recombination with modern humans, that would support the notion that it was a different species, but I know of no evidence to suggest it was a different species. Likewise for Neanderthal and Cro Magnon, for that matter. Why refer to them as different species rather than simply race variants?

If you allow everything to be accounted for by "race variants," then eventually you have all mammals members of the same species.

BTW, Cro Magnon is not a separate species. They are an example of Homo Sapiens.

Harte

originally posted by: Harte

Most of the time that is true, if geographical separation lasts long enough.

Wiki
Accompanying image

Thanks. I am not familiar with those gulls.
Do you know why each of those variants are considered different species?

originally posted by: Origyptian

originally posted by: Harte

Most of the time that is true, if geographical separation lasts long enough.

Wiki
Accompanying image

Thanks. I am not familiar with those gulls.
Do you know why each of those variants are considered different species?

Not specifically, no. I just know that they are, and that they are not the only examples of "ring species."

Harte