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Author | Topic: Ring species as evidence for speciation | |||||||||||||||||||||||
RAZD Member (Idle past 1404 days) Posts: 20714 From: the other end of the sidewalk Joined: |
offspring of mixed mating of horses, donkeys and zebras are not fertile, so mating while it produces offspring is not "successful"
we are limited in our ability to understand by our ability to understand RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}
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macaroniandcheese  Suspended Member (Idle past 3927 days) Posts: 4258 Joined: |
only with donkeys... and only one way (ie if you have a male horse and a female donkey versus the other way. one is fertile, the other isn't). as far as i know. cause they are trying to use horses to bring back an extinct zebra species. but i could be mistaken.
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RAZD Member (Idle past 1404 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Reference I ran into before on this issue is:
Object reference not set to an instance of an object. The second paragraph is where I got the implication that all crosses were sterile (it is not that clear on re-reading). The whole top section is copied from a book and carries this notice:
Reproduced on the webpage from HORSES THROUGH TIME edited by Sandra L. Olsen with permission of Roberts Rinehart Publishers, 6309 Monarch Park Place, Niwot, Colorado 80503. These excerpts may be read only, any printing or reproduction of this material must be obtained in writing from Roberts Rinehart Publishers. The extinct species is the Onager. Also from:http://www.geocities.com/zedonknzorse/basics.html So cross a ZEBRA to a HORSE and you get a ZORSE! Or a zebra stallion to a donkey jennet (mare) and you get a ZEBRASS (also called a zedonk or zonkey). These too are sterile hybrids, and cannot reproduce. Each mule, hinny, zorse or zedonk/zonkey is a one-time shot. Would be interesting to take one of the occasionally fertile female mule and breed with a zebra, eh? enjoy. we are limited in our ability to understand by our ability to understand RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}
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macaroniandcheese  Suspended Member (Idle past 3927 days) Posts: 4258 Joined: |
hm. interesting.
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Steen Inactive Member |
I thought the extinct one was the Quagga?
Anyway, in the example regarding the gulls, we are talking about well-established populations that are well-entrenched in their niches. The Herring Gull and the Lesser Black-Backed Gull are two distinct species. And we can trace all the "transitional" species involved as well, because they are all still alive in different places. As such, that really is an unassailable example of speciation, and I have yet to see a creationist managing to continue supporting the idea of "macro-evolution" as speciation with that example. This message has been edited by Steen, 06-29-2004 08:21 PM
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RAZD Member (Idle past 1404 days) Posts: 20714 From: the other end of the sidewalk Joined: |
oops.
The species described as a "wild ass" in the bible should correctly be called an onager, an Asian species intermediate between donkeys and true horses ... Stephen Jay Gould .. suggesting that the three surviving species of zebra may be more closely related to asses and horses than to each other ...
and
http://www.planetfusion.co.uk/~pignut/equines.htmlAn extinct animal that will never be cloned is the quagga. This relative of the horse once roamed the central plains of Southern Africa by the thousands, but the quagga genome is gone. In the 1800s, European settlers shot all the quaggas in the wild. The quagga was seen as an unwanted grazing competitor to the farmers' livestock, as were all the other grass-eating wild animals. The quagga is gone, but quagga genes may have survived. DNA studies in the 1980s suggested that the quagga is a cousin of the plains zebra, which today roams throughout much of Africa. Researchers compared DNA from a preserved quagga hide in a natural history museum to that of a plains zebra and found in each sample the same stretches of genetic code. In South Africa, the Quagga Project Breeds Success my bad. we are limited in our ability to understand by our ability to understand RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}
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Coragyps Member (Idle past 734 days) Posts: 5553 From: Snyder, Texas, USA Joined: |
Another nice example of a ring species are the greenish warblers that pretty much circle the Tibetan plateau. There are five subspecies, that sort of intergrade into each other - except that the two sorts that share some territory in Siberia don't recognize each others' songs, and don't interbreed. I don't think the paper with the details is online (other than pay-per-view) but the citation is Irwin, et al., Nature 409, 333 - 337 (18 January 2001).
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Steen Inactive Member |
Ah, I have not read about that one before. Thanks a lot.
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Clark Inactive Member |
Can dogs be considered a ring species? Not too many cases I've seen lately of Great Danes mating with Toy Poodles.
And I was informed that's wrong because ring species formed closed loops. But I'm not sure what that means.
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crashfrog Member (Idle past 1466 days) Posts: 19762 From: Silver Spring, MD Joined: |
Can dogs be considered a ring species? Sort of. Generally "ring species" refers to a geographic, as well as genetic, arrangement of species. In other words the populations form a ring around some barrier or obstacle, with adjacent species able to reproduce but distant species unable to do so, culmanating with a species discontinuity at the far side of the ring, representing the point where the population has spread in both directions around the barrier and finally closed the loop. (You might imagine starting with the number "5" at one side of a circle, and counting up in one direction around the circle and counting down to the other. You'd have a situation where at all points on the ring, each number would be one off from the next, except at the opposite side to 5, where 0 and 10 would be right next to each other.) Dog species don't form this kind of physical distribution, but the idea of continuous population with nonmating extremes is the same. They're a sort-of ring species.
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Clark Inactive Member |
I didn't see that the geographic arrangement was so important to the concept. Thanks.
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RAZD Member (Idle past 1404 days) Posts: 20714 From: the other end of the sidewalk Joined: |
are there any instances where all adjacent species can mate but opposite sides can't?
I thought that the fish is Lake Tanganika did that (don't remember the species, a common one, a shallow water fish forming a ring around inside the lake).
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Clark Inactive Member |
Google let me down. I didn't find anything on ring species and cichlids. I did find something on adaptive radiation and Lake Tanganyika cichlids though.
http://www.evolutionsbiologie.uni-konstanz.de/...BE.2001.pdf Lol and I found an final exam from a 100-level college course on evolution. Page Not Found abe: fixed link. This message has been edited by Jamska, 01-14-2005 00:08 AM
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RAZD Member (Idle past 1404 days) Posts: 20714 From: the other end of the sidewalk Joined: |
yep that's the fish. let me sleep on it and I might remember where I saw it.
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Clark Inactive Member |
Thanks. I like these close to home examples. I have a fishtank with African Cichlids about 5 feet from me right now.
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