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Topic: Ring species

	Evolution: Library: Ring Species: Salamanders
		As the species spread southward from Oregon and Washington, subpopulations adapted to their local environments on either side of the San Joaquin Valley.
		A well-studied example of a ring species is the salamander Ensatina eschscholtzii of the Pacific Coast region of the United States.
		Ring species, says biologist David Wake, who has studied Ensatina for more than 20 years, are a beautiful example of species formation in action.
	www.pbs.org /wgbh/evolution/library/05/2/l_052_05.html (710 words)

	Encyclopedia: Ring species
		Ring species, says biologist David Wake, who has studied Ensatina for more than 20 years, are a beautiful example of species formation in action.
		"Ring species are unique because they present all levels of variation, from small differences between neighboring populations to species-level differences, in a single group of organisms," says Irwin, a former student of Price who is in the process of beginning his postdoctoral work with Bensch at Lund University.
		This ring is broken by a species boundary at only one place, in central Siberia, where two forms of the songbird coexist without interbreeding.
	www.nationmaster.com /encyclopedia/Ring-species (1159 words)

	Untitled Document (Site not responding. Last check: 2007-10-10)
		But determining how speciation occurs in any particular case can be difficult, because we are usually only presented with the outcome of the process (two species) and we often have no record of their common ancestor or the intermediate forms that occurred during speciation.
		Ring species show that they are wrong; variation between species is qualitatively similar, though different in degree, to variation within a species.
		Ring species, however, show that the ends of a long chain of interbreeding populations can diverge to the point that they do not directly interbreed, even though genes can travel between them through the intermediate populations (in other words, they are connected by 'gene flow').
	eeb.bio.utk.edu /riechert/news/ring.htm (1849 words)

	Ring Species: Unusual Demonstrations of Speciation by Darren E. Irwin, Ph.D.
		Ring species show that they are wrong; variation between species is qualitatively similar, though different in degree, to variation within a species.
		Ring species, however, show that the ends of a long chain of interbreeding populations can diverge to the point that they do not directly interbreed, even though genes can travel between them through the intermediate populations (in other words, they are connected by 'gene flow').
		Ring species might have existed at one time in habitats such as the grasslands of central North America, but those would now be destroyed or severely altered because of the impact of agriculture.
	www.actionbioscience.org /evolution/irwin.html (2767 words)

	Ring species - Wikipedia, the free encyclopedia
		Ring species illustrate that the species concept is not as clear-cut as it is often understood to be.
		A classic example is the Larus gulls circumpolar species ring.
		However, the Lesser Black-backed gull and Herring gull are sufficiently different that they cannot interbreed; thus the group of gulls forms a ring species.
	en.wikipedia.org /wiki/Ring_species (438 words)

	Levels of Selection, and Speciation Mechanisms, Barry Sinervo
		Ring Species in Salamanders and the Evolution of Mimicry
		Ring Species arise from a peculiar form of allopatric speciation that takes place when the center of a species range is unoccupied because the habitat is unsuitable.
		The ring species of gulls forms a cline in that there are small changes in coloration and behavior of the gulls along the length of the ring.
	bio.research.ucsc.edu /~barrylab/classes/animal_behavior/SPECIATE.HTM (6803 words)

	Ebon Musings (Site not responding. Last check: 2007-10-10)
		Ring species are groups of species that can be arranged in a ring-shaped pattern of increasing dissimilarity.
		Species adjacent to each other on the ring are very similar and can usually interbreed; species across the ring from each other are much more distinct and usually do not interbreed.
		Speciation has also been observed to occur in nature, for instance in the case of new reproductively isolated groups of cichlid fishes forming in African lakes after isolation from the parent population.
	www.ebonmusings.org /evolution/evoevidence.html (5734 words)

	University of California, San Diego: External Relations: News & Information: News Releases : Science
		Their description of the intermediate forms of two reproductively isolated populations of songbirds that no longer interbreed is the "missing evidence" that Darwin had hoped to use to support his theory of natural selection, but was never able to find.
		In the case of the greenish warbler, Phylloscopus trochiloides, the scientists discovered a continuous ring of populations with gradually changing behavioral and genetic characteristics encircling the Tibetan Plateau, which is treeless and uninhabitable.
		At each end of the ring of interbreeding populations, which extend around each side of the Tibetan plateau and through the Himalayas, the scientists found that the two distinct, non-interbreeding forms of the bird do not recognize each other’s songs, which are critical in the selection of their mates.
	ucsdnews.ucsd.edu /newsrel/science/mcwarbler.htm (769 words)

	Useful Tree Species for Tree-Ring Dating
		Douglas-fir is one of the preferred species for dendrochronology in the western portions of North America.
		The rings are also well defined - in other words, there is a sharp definition between the earlywood (wood formed early in the growing season) and latewood (wood formed later in the growing season).
		Because ring-porous species almost always begin annual growth with this initial flush, missing rings are rare in such species as oak and elm.
	www.ltrr.arizona.edu /lorim/good.html (897 words)

	Evolution - A-Z - Ring species (Site not responding. Last check: 2007-10-10)
		A ring species is a situation in which two populations which do not interbreed are living in the same region and connected by a geographic ring of populations that can interbreed.
		Famous examples of ring species are the herring and lesser fl-backed gulls in northern Europe and the Ensatina salamanders of California.
		Consider a species that is geographically distributed in a straight line from east to west across America: it is possible that the forms in the east and west are so different that they could not interbreed.
	www.blackwellpublishing.com /ridley/a-z/Ring_species.asp (244 words)

	CB910: New species
		In ring species, the species is distributed more or less in a line, such as around the base of a mountain range.
		Evidence of speciation occurs in the form of organisms that exist only in environments that did not exist a few hundreds or thousands of years ago.
		Some young-earth creationists claim that speciation is essential to explain Noah's ark. The ark was not roomy enough to carry and care for all species, so speciation is invoked to explain how the much fewer "kinds" aboard the ark became the diversity we see today.
	www.talkorigins.org /indexcc/CB/CB910.html (807 words)

	Boreal Forests of the World Bird Species - Ring-necked Pheasant (Site not responding. Last check: 2007-10-10)
		The colourful male with a 40 - 45 cm long tapered tail, a rooster-like bill and spurred tarsus is a striking bird.
		The white ring around the neck varies in depth and is sometimes lacking.
		Populations introduced from several sub-species are now mingled and composite in this species only.
	www.borealforest.org /world/birds/ring_necked_pheasant.htm (124 words)

	RING SPECIES
		"Ring Species: Unusual Demonstrations of Speciation" by Darren E. Irwin, Ph.D. The striking article above is from ActionBioscience, considered by Scientific American to be of the best science sites on the internet.
		These species are the diamonds of natural selection which can be observed in nature in Ring Species (Explored in the above link).
		Our species' history, due to several branches of science is seen in the same way, with slow speciation until one branch becomes so different that it can no longer interbreed with its ring neighbors.
	community.webtv.net /tales_of_the_western_world/RINGSPECIES (550 words)

	Ring Species: An Introduction
		Ring Species: Unusual Demonstrations of Speciation by Darren E. Irwin, perhaps the best explanation on the Internet for the layman, discusses both salamanders and greenish warblers.
		Ring species occur when one species grades into two at the overlap of a circular population distribution.
		One species of each sympatric pair is a large-bodied Benthic that feeds on invertebrates in the littoral zone; the other species is a smaller, more slender Limnetic that feeds primarily on plankton in open water.
	www.wwdd2.net /ringspecies.html (1676 words)

	Species Enigma
		If a species could only be defined if its members were shown to be reproductively compatible, the only way to finally prove the point would be to conduct countless breeding experiments and discover which hybrid offspring were sterile or stillborn.
		At present, it is usually the number of species in a particular habitat that is taken as a measure of the value of the environment in conservation terms.
		But all species definitions have been shown to have their limitations, and perhaps it is unrealistic to assume that we can impose and apply a single definition on a natural world made restless by evolutionary change.
	www.dhushara.com /book/diversit/extra/enig/senig.htm (3435 words)

	Species Showcase - The Lovebird - PetStation
		All nine species are in the genus AGAPORNIS.
		Of the eight remaining species of lovebirds the Masked are the most readily available of the eye-ring species, so named because of the featherless ring around their eyes.
		The eye-ring species of lovebirds are not as prolific in captivity as the peach-face.
	www.petstation.com /lovebird.html (1055 words)

	BBC News \| SCI/TECH \| Songbird shows how evolution works
		The Himalayan warblers are an example of a rare condition known as a "ring species".
		"Ring species are unique because they present all levels of variation, from small differences between neighbouring populations to species-level differences in a single group of organisms," says Irwin.
		"Ring species are valuable because they can show all of the intermediate steps that occur during the divergence of one species into two.
	news.bbc.co.uk /hi/english/sci/tech/newsid_1123000/1123973.stm (524 words)

	Notes on the Eye-Ring Lovebirds Fischer's Nyasa Masked Black-cheeked
		This group is made up of four separate and distinct species: the masked (A. personata), the Fischer's (A. fischeri), the fl-cheeked (A. nigrigenis) and the Nyasa (A. lilianae) Love Birds.
		In their natural coloration, all four species have characteristics that make them similar in appearance: the eye-ring, a red beak and a green body.The mask and the Fischers are about the same size (6 inches long), with waxy red bills and blue-colored rumps.
		The eye-ring species are rewarding to work with in that they are fairly consistent in their breeding efforts.
	www.africanlovebirdsociety.com /species/eyering.htm (1667 words)

	BIOL1051 - Biodiversity 1 - Lecture 2 (Site not responding. Last check: 2007-10-10)
		There are several ring species, the most famous example is the herring gull (Larus argentatus).
		An understanding of the process of speciation is often gained by studying geographic variation and, perhaps, the pattern seen in ring species is the most informative.
		In the case of ring species, like the gulls, the intermediates are still alive which is not normally the case.
	scitec.uwichill.edu.bb /bcs/courses/Biology/BL14A/bl14al02.htm (1374 words)

	Biological species concept
		The biological species concept defines a species as members of populations that actually or potentially interbreed in nature, not according to similarity of appearance.
		Ring species are species with a geographic distribution that forms a ring and overlaps at the ends.
		Obviously, chronospecies present a problem for the biological species concept — for example, it is not really possible (or very meaningful!) to figure out whether a trilobite living 300 million years ago would have interbred with its ancestor living 310 million years ago.
	evolution.berkeley.edu /evolibrary/article/side_0_0/biospecies_01 (482 words)

	Ring species - Encyclopedia, History, Geography and Biography
		A recent genetic study has shown that this example is far more complicated than presented here.
		This encyclopedia, history, geography and biography article about Ring species contains research on
		Ring species, External links, Scientific classification and Speciation.
	www.arikah.net /encyclopedia/Ring_species (438 words)

	Adopt a Ring-tailed Lemur - National Zoo\| FONZ
		The 88 species of lemurs can be found in habitats as different as the lush, wet, rainforest of eastern Madagascar and the dry spiny desert in the southwest.
		The species living today are small to medium-size mammals ranging from the smallest of all primatesâ”the tiny pygmy mouse lemur, which weighs only one ounceâ”to the largest lemurs, the indri and the diademed sifaka, which weigh slightly over 15 pounds and can reach four-feet tall.
		The smaller species tend to be nocturnal and solitary, but most of the larger species are active during the day.
	nationalzoo.si.edu /Support/AdoptSpecies/AnimalInfo/Lemur/default.cfm (1113 words)

	29+ Evidences for Macroevolution: References
		Hudson, R. (1992) "Gene trees, species trees and the segregation of ancestral alleles." Genetics 131: 509-513.
		Nichols, R. (2001) "Gene trees and species trees are not the same." Trends Ecol Evol.
		Wu, C. (1991) "Inferences of species phylogeny in relation to segregation of ancient polymorphisms." Genetics 127: 429-435.
	www.talkorigins.org /faqs/comdesc/refs.html (6565 words)

	MSN Encarta - Search Results - Ring Species
		Ring Species, species distributed geographically as a circle or ring, the end forms of which do not interbreed.
		Gaillardia, genus of about 28 American herbs of the daisy family named after Gaillard de Marentonneau, a French amateur botanist.
		The largest genus contains about 30 species, many of which have dark “rings” or “belts” across their upper breasts.
	uk.encarta.msn.com /Ring_Species.html (106 words)

	Evolution 1:
		Although they are rare, we can learn a lot from ring species.
		Instead of being a ring species, 'Herring Gulls' seem to have spread eastwards from two refugia: the NE Atlantic and the area around the Aral and Caspian Seas.
		These birds might become a ring species if the Lesser Black-backed Gull Larus fuscus colonizes N America, where records have increased dramatically recently.
	www.lifesci.sussex.ac.uk /teaching/C1010/rings.htm (255 words)

	Loren Rieseberg: Publications (Site not responding. Last check: 2007-10-10)
		Selection on leaf ecophysiological traits in a hybrid Helianthus species and early generation hybrids in a desert dune habitat.
		Origin(s) of the diploid hybrid species Helianthus deserticola (Asteraceae).
		Hybrid speciation accompanied by genomic reorganization in wild sunflowers.
	www.bio.indiana.edu /~rieseberglab/pubs.html (2517 words)

	Species Profile: Ring-necked Duck by Richard Ditch
		A dark brown ring at the base of the neck is hard to see in the field but readily apparent in the hand.
		Related or Similar Species: Ring-necked Ducks are in the Aythya family which includes Greater Scaup, Lesser Scaup, Canvasback, and Redhead in North America, and the Tufted Duck and Pochard in Europe.
		After moving to Phoenix, AZ in 1994 as a result of a job change, he found the birds to be a lot different and went through a rapid period of learning new species and new forms of species East.
	www.photomigrations.com /articles/0301200.htm (801 words)

	Ring Species (Site not responding. Last check: 2007-10-10)
		There are several ring species, but the most famous example is the herring gull.
		There is a bird species which rings the Tibetan plateau.
		Two species are the same if there is "significant" gene flow between them.
	www.don-lindsay-archive.org /creation/ring_species.html (234 words)

	TheOneRing.net™\| Lord of the Rings Movie News and Rumors
		Special effects king Richard Taylor will fly the Kiwi flag in Monaco this week amid the world's leading entrepreneurs, a prospect he finds daunting.
		This may be too little too late, however I now have the clips from Orlando Bloom's visit to 'The Tonight Show with Jay Leno' from earlier this month.
		TheOneRing® is a registered service mark with exclusive right to grant use assigned to The One Ring, Inc. Binary hosting provided by Nexcess.net.
	www.theonering.net (1221 words)

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