Freethought & Rationalism Archive

demoninho · 08-07-2003, 08:32 AM

Hi,

does anybody know of any examples where species B can interbreed with species A or C and can have fertile offspring but A and C can not?

Wounded King · 08-07-2003, 08:39 AM

There are several instances of this, they are called 'ring species'. Perhaps the most well known is that of the herring gull populations in the arctic.

This website gives details of another example in salamanders.

And this

Quote:

Incipient species formation in salamanders of the Ensatina complex.

Wake DB.

Proc Natl Acad Sci U S A. 1997 Jul 22;94(15):7761-7.

Museum of Vertebrate Zoology and Department of Integrative Biology, University of California, Berkeley, CA 94720-3160, USA. wakelab@uclink4.berkeley.edu

The Ensatina eschscholtzii complex of plethodontid salamanders, a well-known "ring species," is thought to illustrate stages in the speciation process. Early research, based on morphology and coloration, has been extended by the incorporation of studies of protein variation and mitochondrial DNA sequences. The new data show that the complex includes a number of geographically and genetically distinct components that are at or near the species level. The complex is old and apparently has undergone instances of range contraction, isolation, differentiation, and then expansion and secondary contact. While the hypothesis that speciation is retarded by gene flow around the ring is not supported by molecular data, the general biogeographical hypothesis is supported. There is evidence of a north to south range expansion along two axes, with secondary contact and completion of the ring in southern California. Current research targets regions once thought to show primary intergradation, but which molecular markers reveal to be zones of secondary contact. Here emphasis is on the subspecies E. e. xanthoptica, which is involved in four distinct secondary contacts in central California. There is evidence of renewed genetic interactions upon recontact, with greater genetic differentiation within xanthoptica than between it and some of the interacting populations. The complex presents a full array of intermediate conditions between well-marked species and geographically variable populations. Geographically differentiated segments represent a diversity of depths of time of isolation and admixture, reflecting the complicated geomorphological history of California. Ensatina illustrates the continuing difficulty in making taxonomic assignments in complexes studied during species formation.

Is one of the papers it references with a link to the full text online.

demoninho · 08-07-2003, 08:46 AM

Ah I read something once about a species of bird living around the Himalaya mountain range. The two ends were able to mate but just did not choose each other because their songs were to different. But could we make fertile offspring in a laboratory with both ends of the cirkel in these herrings?

Dr.GH · 08-07-2003, 09:06 AM

I have read of some artificial insemination experiments that indicated thate viable cross fertilizations can occur across ring species. This speaks directly to the common creationist question, "What do members of new species mate with?" Individuals don't evovle- populations evolve.

Wounded King · 08-07-2003, 02:46 PM

Maybe next time some creationist complain that speciation has never been observed taking place we should just go out and cull all the intermediate sub species from a rig species.

Clutch · 08-07-2003, 02:59 PM

When I first read about the Ensatina complex in biology class, I thought, "That's it! No sane person could deny ongoing speciation in the face of this!"

Naive to the last, me.

Coragyps · 08-07-2003, 06:13 PM

This page on the pretty informative website Actionbioscience is a nice quick view of the salamander and greenish warbler rings of species. But still no answer to your question in the OP, demoninho.

Worldtraveller · 08-08-2003, 01:34 AM

Is this the same process as hybrid bird species?

I'm not a biologist, but I am a fairly avid birdwatcher, and there are a number of species listed in my books as 'hybrids' that occur where two seperate species overlap.

Does anyone have information on whether these hybrids tend to breed with each other, or with one of the 'parent' species? It seems to me like the hybrid species could, with a little change in habitat (isolation), become a new species.

Thanks for the links. Interesting stuff.

Lane

Claudia · 08-08-2003, 01:42 AM

No, ring species are not hybrids, because the species at the two ends do not mate (->no hybrid). But it is true that they can often have viable offsprings when scientist succeed in having them mating (which does not happens in neature, again)

Wounded King · 08-08-2003, 02:34 AM

Why do you feel the opening post has not been addressed Coragyps, because we are talking about subspecies rather than seperate species?

08-07-2003, 08:32 AM	#1
demoninho Senior Member Join Date: May 2003 Location: The Netherlands Posts: 927	Species interbreeding Hi, does anybody know of any examples where species B can interbreed with species A or C and can have fertile offspring but A and C can not?

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08-07-2003, 08:46 AM	#3
demoninho Senior Member Join Date: May 2003 Location: The Netherlands Posts: 927	Ah I read something once about a species of bird living around the Himalaya mountain range. The two ends were able to mate but just did not choose each other because their songs were to different. But could we make fertile offspring in a laboratory with both ends of the cirkel in these herrings?

08-07-2003, 09:06 AM	#4
Dr.GH Veteran Member Join Date: Jul 2001 Location: Dana Point, Ca, USA Posts: 2,115	I have read of some artificial insemination experiments that indicated thate viable cross fertilizations can occur across ring species. This speaks directly to the common creationist question, "What do members of new species mate with?" Individuals don't evovle- populations evolve.

08-07-2003, 02:46 PM	#5
Wounded King Veteran Member Join Date: Mar 2003 Location: Edinburgh Posts: 1,211	Maybe next time some creationist complain that speciation has never been observed taking place we should just go out and cull all the intermediate sub species from a rig species.

08-07-2003, 02:59 PM	#6
Clutch Veteran Member Join Date: Oct 2001 Location: Canada Posts: 3,751	When I first read about the Ensatina complex in biology class, I thought, "That's it! No sane person could deny ongoing speciation in the face of this!" Naive to the last, me.

08-07-2003, 06:13 PM	#7
Coragyps Veteran Join Date: Aug 2001 Location: Snyder,Texas,USA Posts: 4,411	This page on the pretty informative website Actionbioscience is a nice quick view of the salamander and greenish warbler rings of species. But still no answer to your question in the OP, demoninho.

08-08-2003, 01:34 AM	#8
Worldtraveller Banned Join Date: Apr 2003 Posts: 7,834	Is this the same process as hybrid bird species? I'm not a biologist, but I am a fairly avid birdwatcher, and there are a number of species listed in my books as 'hybrids' that occur where two seperate species overlap. Does anyone have information on whether these hybrids tend to breed with each other, or with one of the 'parent' species? It seems to me like the hybrid species could, with a little change in habitat (isolation), become a new species. Thanks for the links. Interesting stuff. Lane

08-08-2003, 01:42 AM	#9
Claudia Senior Member Join Date: Apr 2001 Location: France Posts: 715	No, ring species are not hybrids, because the species at the two ends do not mate (->no hybrid). But it is true that they can often have viable offsprings when scientist succeed in having them mating (which does not happens in neature, again)

08-08-2003, 02:34 AM	#10
Wounded King Veteran Member Join Date: Mar 2003 Location: Edinburgh Posts: 1,211	Why do you feel the opening post has not been addressed Coragyps, because we are talking about subspecies rather than seperate species?

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